MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Journal of Evolutionary Biology' source. Thu, 09 Feb 2012 14:32:11 +0100 http://www.medworm.com/index.php?rid=5673784&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02462.x AbstractAn approach frequently used to demonstrate a genetic basis for population‐level phenotypic differences is to employ common garden rearing designs, where observed differences are assumed to be attributable to primarily additive genetic effects. Here, in two common garden experiments, we employed factorial breeding designs between wild and domestic, and among wild populations of Chinook salmon (Oncorhynchus tshawytscha). We measured the contribution of additive (VA) and maternal (VM) effects to the observed population differences for 17 life history and fitness‐related traits. Our results show that, in general, maternal effects contribute more to phenotypic differences among populations than additive genetic effects. These results suggest that maternal effects are important in po... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673784 Thu, 09 Feb 2012 05:00:00 +0100 5673784 http://www.medworm.com/index.php?rid=5673783&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02466.x In this study, we look for such evidence in a natural population of Drosophila melanogaster. We compared mating and nonmating individuals to test whether mating was nonrandom with respect to relatedness. Consistent with optimal inbreeding, males were more closely related to their mate than to randomly sampled females. However, all individuals collected mating showed higher relatedness and males were not significantly more related to their mate than to other mating females. We also found a negative relationship between relatedness and fecundity. Our results are consistent with the hypothesis that inclusive fitness benefits may drive inbreeding tolerance despite direct costs to fitness; however, an experimental approach is needed to investigate the link between mate preference and relatednes... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673783 Thu, 09 Feb 2012 05:00:00 +0100 5673783 http://www.medworm.com/index.php?rid=5673782&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02468.x AbstractWhy sexual reproduction has evolved to be such a widespread mode of reproduction remains a major question in evolutionary biology. Although previous studies have shown that increased sex and recombination can evolve in the presence of host–parasite interactions (the ‘Red Queen hypothesis’ for sex), many of these studies have assumed that multiple loci mediate infection vs. resistance. Data suggest, however, that a major locus is typically involved in antigen presentation and recognition. Here, we explore a model where only one locus mediates host–parasite interactions, but a second locus is subject to directional selection. Even though the effects of these genes on fitness are independent, we show that increased rates of sex and recombination are favoured at a modifier gene... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673782 Thu, 09 Feb 2012 05:00:00 +0100 5673782 http://www.medworm.com/index.php?rid=5673781&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02467.x AbstractDrosophila madeirensis is an endemic species of Madeira that inhabits the island Laurisilva forest. Nucleotide variation in D. madeirensis is analysed in six genomic regions and compared to that previously reported for the same regions in Drosophila subobscura, an abundant species in the Palearctic region that is closely related to D. madeirensis. The gene regions analysed are distributed along the O3 inversion. The O3 arrangement is monomorphic in D. madeirensis, and it was present in ancestral populations of D. subobscura but went extinct in this species after the origin of the derived OST and O3+4 arrangements. Levels of nucleotide polymorphism in D. madeirensis are similar to those present in the OST and O3+4 arrangements of D. subobscura, and the frequency spectrum is sk... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673781 Thu, 09 Feb 2012 05:00:00 +0100 5673781 http://www.medworm.com/index.php?rid=5673780&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02470.x AbstractThe current, virtually worldwide distribution of the house sparrow (Passer domesticus) is a result of its commensal relationship with humans. It has been suggested that long before the advent of agriculture, an early glacial advance resulted in two disjunct ranges of ancestral house sparrows – one in the Middle East and another on the Indian subcontinent. Differentiation during this period of isolation resulted in two major groups of subspecies: the domesticus group and the indicus group. According to this hypothesis, commensalism with humans would have evolved independently in the two regions and at least twice. An alternative hypothesis is that morphological differences between the subspecies represent very recent differentiation, following expansions from a single source. To t... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673780 Thu, 09 Feb 2012 05:00:00 +0100 5673780 http://www.medworm.com/index.php?rid=5656247&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02461.x Abstract Determining the mechanisms that generate population structure is essential to the understanding of speciation and the evolution of biodiversity. Here, we investigate a geographical range that transects two habitat gradients, the North Sea to North Atlantic transition, and the temperate to subpolar regions. We studied the harbour porpoise (Phocoena phocoena), a small odontocete inhabiting both subpolar and temperate waters. To assess differentiation among putative populations, we measured morphological variation at cranial traits (N = 462 individuals) and variation at eight microsatellite loci for 338 of the same individuals from Norwegian, British and Danish waters. Significant morphological differentiation reflected the size of the buccal cavity. Porpoises forage in relativel... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5656247 Thu, 02 Feb 2012 05:00:00 +0100 5656247 http://www.medworm.com/index.php?rid=5656246&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02463.x AbstractTheory predicts that geographic variation in traits and genes associated with climatic adaptation may be initially driven by the correlated evolution of thermal preference and thermal sensitivity. This assumes that an organism’s preferred body temperature corresponds with the thermal optimum in which performance is maximized; hence, shifts in thermal preferences affect the subsequent evolution of thermal‐related traits. Drosophila subobscura evolved worldwide latitudinal clines in several traits including chromosome inversion frequencies, with some polymorphic inversions being apparently associated with thermal preference and thermal tolerance. Here we show that flies carrying the warm‐climate chromosome arrangement O3+4 have higher basal protein levels of Hsp70 than their co... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5656246 Thu, 02 Feb 2012 05:00:00 +0100 5656246 http://www.medworm.com/index.php?rid=5656245&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02464.x AbstractEvolutionary transitions between marine and freshwater biomes are relatively rare events, yielding a widespread pattern of biome conservatism among aquatic organisms. We investigated biome transitions in anchovies (Engraulidae), a globally distributed clade of economically important fishes. Most anchovy species are near‐shore marine fishes, but several exclusively freshwater species are known from tropical rivers of South America and were previously thought to be the product of six or more independent freshwater invasions. We generated a comprehensive molecular phylogeny for Engraulidae, including representatives from 15 of 17 currently recognized genera. Our data support previous hypotheses of higher‐level relationships within Engraulidae, but show that most New World genera a... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5656245 Thu, 02 Feb 2012 05:00:00 +0100 5656245 http://www.medworm.com/index.php?rid=5673779&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02471.x AbstractPopulation divergence in antipredator defence and behaviour occurs rapidly and repeatedly. Genetic differences, phenotypic plasticity or parental effects may all contribute to divergence, but the relative importance of each of these mechanisms remains unknown. We exposed juveniles to parents and predators to measure how induced changes contribute to shoaling behaviour differences between two threespine stickleback species (benthics and limnetics: Gasterosteus spp). We found that limnetics increased shoaling in response to predator attacks, whereas benthics did not alter their behaviour. Care by limnetic fathers led to increased shoaling in both limnetic and benthic offspring. Shoaling helps limnetics avoid trout and avian predation; our results suggest that this adaptive behaviour ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5673779 Wed, 01 Feb 2012 05:00:00 +0100 5673779 http://www.medworm.com/index.php?rid=5656248&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02459.x This study explored the evolution of body fluid regulation following freshwater invasions by the copepod Eurytemora affinis. The goals of this study were to determine (1) whether invasions from saline to freshwater habitats were accompanied by evolutionary shifts in body fluid regulation (hemolymph osmolality) and (2) whether parallel shifts occurred during independent invasions. We measured hemolymph osmolality for ancestral saline and freshwater invading populations reared across a range of common‐garden salinities (0.2–25 PSU). Our results revealed the evolution of increased hemolymph osmolality (by 16–31%) at lower salinities in freshwater populations of E. affinis relative to their saline ancestors. Moreover, we observed the same evolutionary shifts across two independent fres... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5656248 Wed, 01 Feb 2012 05:00:00 +0100 5656248 http://www.medworm.com/index.php?rid=5656244&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02465.x AbstractShared behavioural, morphological and physiological characteristics are indicative of the evolution of extant birds from nonavian maniraptoran dinosaurs. One such shared character is the presence of uncinate processes and respiratory structures in extant birds. Recent research has suggested a respiratory role for these processes found in oviraptorid and dromaeosaurid dinosaurs. By measuring the geometry of fossil rib cage morphology, we demonstrate that the mechanical advantage, conferred by uncinate processes, for movements of the ribs in the oviraptorid theropod dinosaur, Citipati osmolskae, basal avialan species Zhongjianornis yangi, Confuciusornis sanctus and the more derived ornithurine Yixianornis grabaui, is of the same magnitude as found in extant birds. These skeletal char... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5656244 Wed, 01 Feb 2012 05:00:00 +0100 5656244 http://www.medworm.com/index.php?rid=5624574&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02458.x AbstractA major goal of evolutionary biology is to explain morphological diversity among species. Many studies suggest that much morphological variation is explained by adaptation to different microhabitats. Here, we test whether morphology and microhabitat use are related in plethodontid salamanders, which contain the majority of salamander species, and have radiated into a striking diversity of microhabitats. We obtained microhabitat data for 189 species that also had both morphometric and phylogenetic data. We then tested for associations between morphology and microhabitat categories using phylogenetic comparative methods. Associations between morphology and ecology in plethodontids are largely confined to a single clade within one subfamily (Bolitoglossinae), whereas variation in morp... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624574 Tue, 24 Jan 2012 19:43:12 +0100 5624574 http://www.medworm.com/index.php?rid=5624576&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02450.x AbstractSubstantial additive genetic variance (VA) often exists for male signalling traits in spite of the directional selection that female choice imposes. One solution to this problem, a conundrum generally termed the ‘lek paradox’, is that genotype × environment interaction (GEI) occurs and generates a ‘crossover’ of reaction norms in which no one genotype performs in a superior manner in all environments. Theoretical work indicates that such crossover can sustain genetic variance provided that either (i) spatial heterogeneity in environmental conditions combined with limited migration among populations or (ii) temporal heterogeneity in environmental conditions combined with occasional generation overlap is present. Whereas some recent studies have revealed the intersection... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624576 Tue, 24 Jan 2012 05:00:00 +0100 5624576 http://www.medworm.com/index.php?rid=5624575&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02460.x We report on a Gehyra population that displays extraordinary body size differentiation in comparison with other G. variegata species. We used morphological and environmental data to show this population is phenotypically and ecologically distinct from its parapatric congener Gehyra lazelli and that morphology and ecology are significantly correlated. Contrastingly, mtDNA analysis indicates paraphyly between the two groups, and allele frequencies at six microsatellite loci show no population structure concordant with morpho‐/ecotype. These results suggest either ecological speciation or environmentally induced phenotypic polymorphism, in an otherwise morphologically conservative group. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624575 Tue, 24 Jan 2012 05:00:00 +0100 5624575 http://www.medworm.com/index.php?rid=5624583&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02446.x AbstractHost–parasite systems have been models for understanding the connection between shifts in resource use and diversification. Despite theoretical expectations, ambiguity remains regarding the frequency and importance of host switches as drivers of speciation in herbivorous insects and their parasitoids. We examine phylogenetic patterns with multiple genetic markers across three trophic levels using a diverse lineage of geometrid moths (Eois), specialist braconid parasitoids (Parapanteles) and plants in the genus Piper. Host–parasite associations are mapped onto phylogenies, and levels of cospeciation are assessed. We find nonrandom patterns of host use within both the moth and wasp phylogenies. The moth–plant associations in particular are characterized by small radiations of m... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624583 Mon, 23 Jan 2012 05:00:00 +0100 5624583 http://www.medworm.com/index.php?rid=5624582&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02453.x We examined whether ovipositor length (OL) and egg shape correlated with differences in host mussel species in the family Unionidae among populations of the tabira bitterling (Acheilognathus tabira) in Japan. Bitterling populations that use mussels in the sub‐family Anodontinae possessed longer ovipositors and more elongated eggs than those using mussels of Unioninae, as expected from the difference in host size between the sub‐families (anodontine mussels are larger than unionine mussels). Based on a robust phylogeny of A. tabira populations, we demonstrated that the evolution of both OL and egg shape were correlated with host differences, but not with each other, suggesting that these traits have been selected for independently. Our study demonstrates how adaptive traits for brood pa... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624582 Mon, 23 Jan 2012 05:00:00 +0100 5624582 http://www.medworm.com/index.php?rid=5624581&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02454.x We present a model for the advantage of sexual reproduction in multicellular long‐lived species in a world of structured resources in short supply. The model combines features of the Tangled Bank and the Red Queen hypothesis of sexual reproduction and is of broad applicability. The model is ecologically explicit with the dynamics of resources and consumers being modelled by differential equations. The life history of consumers is shaped by body mass‐dependent rates as implemented in the metabolic theory of ecology. We find that over a broad range of parameters, sexual reproduction wins despite the two‐fold cost of producing males, due to the advantage of producing offspring that can exploit underutilized resources. The advantage is largest when maturation and production of offspring ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624581 Mon, 23 Jan 2012 05:00:00 +0100 5624581 http://www.medworm.com/index.php?rid=5624580&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02455.x AbstractAlthough the spatial separation of sexual organs within a flower (herkogamy) has been interpreted as a mechanism that promotes efficient pollen transfer, there have been few attempts to relate variation in herkogamy to probabilities of pollen flow. Here, we used a heterostylous species with variation in reciprocal herkogamy to test this hypothesis. We measured legitimate and illegitimate pollen flow with fluorescent dyes in four selected populations of Oxalis alpina corresponding to the extremes of a previously reported evolutionary gradient from tristyly to distyly. After the breakdown of tristyly, the observed increment in reciprocal herkogamy between the long and short morphs was associated with a 30% increase in the proportion of dye received from compatible illegitimate pollin... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624580 Mon, 23 Jan 2012 05:00:00 +0100 5624580 http://www.medworm.com/index.php?rid=5624579&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02456.x AbstractConsistent individual differences in behaviour, and behavioural correlations within and across contexts, are referred to as animal personalities. These patterns of variation have been identified in many animal taxa and are likely to have important ecological and evolutionary consequences. Despite their importance, genetic and environmental sources of variation in personalities have rarely been characterized in wild populations. We used a Bayesian animal model approach to estimate genetic parameters for aggression, activity and docility in North American red squirrels (Tamiasciurus hudsonicus). We found support for low heritabilities (0.08–0.12), and cohort effects (0.07–0.09), as well as low to moderate maternal effects (0.07–0.15) and permanent environmental effects (0.08–... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624579 Mon, 23 Jan 2012 05:00:00 +0100 5624579 http://www.medworm.com/index.php?rid=5624578&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2012.02457.x AbstractThe mandibular symphyseal joint is remarkably variable across major mammalian clades, ranging in adults from unfused (amphiarthrosis) to partially fused (synarthrosis) to completely ossified (synostosis). Experimental work conducted on primates suggests that greater ossification of the symphysis is a response to increased recruitment of the balancing‐side (i.e. nonchewing side) jaw‐adductor muscles during forceful unilateral biting and chewing, with increased fusion strengthening the symphysis against correspondingly elevated joint stresses. It is thus expected that species with diets composed primarily of foods that require high‐magnitude bite forces and/or repetitive loading to process will be characterized by greater degrees of symphyseal ossification than species with rel... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624578 Mon, 23 Jan 2012 05:00:00 +0100 5624578 http://www.medworm.com/index.php?rid=5624577&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02451.x AbstractIt is a challenge to measure sexual selection because both stochastic events (chance) and deterministic factors (selection) generate variation in individuals’ reproductive success. Most researchers realize that random events (‘noise’) make it difficult to detect a relationship between a trait and mating success (i.e. the presence of sexual selection). There is, however, less appreciation of the dangers that arise if stochastic events vary systematically. Systematic variation makes variance‐based approaches to measuring the role of selection problematic. This is why measuring the opportunity for sexual selection (Is and Imates) is so vulnerable to misinterpretation. Although Is does not measure actual sexual selection (because it includes stochastic variation in mating/ferti... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5624577 Mon, 23 Jan 2012 05:00:00 +0100 5624577 http://www.medworm.com/index.php?rid=5616852&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02449.x AbstractThe primary feathers of birds are subject to cyclical forces in flight causing their shafts (rachises) to bend. The amount the feathers deflect during flight is dependent upon the flexural stiffness of the rachises. By quantifying scaling relationships between body mass and feather linear dimensions in a large data set of living birds, we show that both feather length and feather diameter scale much closer to predictions for geometric similarity than they do to elastic similarity. Scaling allometry also indicates that the primary feathers of larger birds are relatively shorter and their rachises relatively narrower, compared to those of smaller birds. Two‐point bending tests indicated that larger birds have more flexible feathers than smaller species. Discriminant functional anal... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5616852 Sat, 21 Jan 2012 19:12:13 +0100 5616852 http://www.medworm.com/index.php?rid=5616853&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02448.x (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5616853 Thu, 19 Jan 2012 05:00:00 +0100 5616853 http://www.medworm.com/index.php?rid=5592817&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02447.x Abstract The faunas associated with oceanic islands provide exceptional examples with which to examine the dispersal abilities of different taxa and test the relative contribution of selective and neutral processes in evolution. We examine the patterns of recent differentiation and the relative roles of gene flow and selection in genetic and morphological variation in the yellow warbler (Dendroica petechia aureola) from the Galápagos and Cocos Islands. Our analyses suggest aureola diverged from Central American lineages colonizing the Galápagos and Cocos Islands recently, likely less than 300 000 years ago. Within the Galápagos, patterns of genetic variation in microsatellite and mitochondrial markers suggest early stages of diversification. No intra‐island patterns of morphologic... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592817 Sun, 15 Jan 2012 08:29:05 +0100 5592817 http://www.medworm.com/index.php?rid=5592821&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02408.x AbstractIn Tribolium flour beetles and other organisms, individuals migrate between heterogeneous environments where they often encounter markedly different nutritional conditions. Under these circumstances, theory suggests that genotype‐by‐environment interactions (GEI) may be important in facilitating adaptation to new environments and maintaining genetic variation for male traits subject to directional selection. Here, we used a nested half‐sib breeding design with Tribolium castaneum to partition the separate and joint effects of male genotype and nutritional environment on phenotypic variation in a comprehensive suite of life‐history traits, reproductive performance measures across three sequential sexual selection episodes, and fitness. When male genotypes were tested across ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592821 Fri, 13 Jan 2012 05:00:00 +0100 5592821 http://www.medworm.com/index.php?rid=5592820&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02443.x AbstractDivergent selection stemming from environmental variation may induce local adaptation and ecological speciation whereas gene flow might have a homogenizing effect. Gene flow among populations using different environments can be reduced by geographical distance (isolation‐by‐distance) or by divergent selection stemming from resource use (isolation‐by‐ecology). We tested for and encountered phenotypic and genetic divergence among Spanish crossbills utilizing different species of co‐occurring pine trees as their food resource. Morphological, vocal and mtDNA divergence were not correlated with geographical distance, but they were correlated with differences in resource use. Resource diversity has now been found to repeatedly predict crossbill diversity. However, when resource... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592820 Fri, 13 Jan 2012 05:00:00 +0100 5592820 http://www.medworm.com/index.php?rid=5592819&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02445.x AbstractPositive correlations between heterozygosity and fitness traits are frequently observed, and it has been hypothesized, but rarely tested experimentally, that parasites play a key role in mediating the heterozygosity–fitness association. We evaluated this hypothesis in a wild great tit (Parus major) population by testing the prediction that the heterozygosity–fitness association would appear in broods experimentally infested with a common ectoparasite, but not in parasite‐free broods. We simultaneously assessed the effects of parental and offspring heterozygosity on nestling growth and found that body mass of nestlings close to independence, which is a strong predictor of post‐fledging survival, increased significantly with nestling levels of heterozygosity in experimentally... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592819 Fri, 13 Jan 2012 05:00:00 +0100 5592819 http://www.medworm.com/index.php?rid=5592818&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02444.x AbstractBody size and morphology are key fitness‐determining traits that can vary genotypically. They are likely to be important in social insect queens, which mate in swarms and found colonies independently, but genetic influences on queen morphology have been little investigated. Here, we show that the body size and morphology of queens are influenced by their genotype in the leaf‐cutting ant Acromyrmex echinatior, a species in which certain lineages (patrilines) bias their development towards reproductive queens rather than sterile workers. We found no relationship between the queen‐worker skew of patrilines and the size or morphology of queens, but there was a significant relationship with fluctuating asymmetry, which was greater in more queen‐biased patrilines. Our results sug... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592818 Fri, 13 Jan 2012 05:00:00 +0100 5592818 http://www.medworm.com/index.php?rid=5592822&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02439.x AbstractBehavioural ecologists have proposed various evolutionary mechanisms as to why different personality types coexist. Our ability to understand the evolutionary trajectories of personality traits requires insights from the quantitative genetics of behavioural reaction norms. We assayed > 1000 pedigreed stickleback for initial exploration behaviour of a novel environment, and subsequent changes in exploration over a few hours, representing their capacity to adjust their behaviour to changes in perceived novelty and risk. We found heritable variation in both the average level of exploration and behavioural plasticity, and population differences in the sign of the genetic correlation between these two reaction norm components. The phenotypic correlation was not a good indicator of ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5592822 Wed, 11 Jan 2012 05:00:00 +0100 5592822 http://www.medworm.com/index.php?rid=5568641&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02435.x AbstractEvolutionary theory predicts that herbivorous insects should lay eggs on plants in a way that reflects the suitability of each plant species for larval development. Empirical studies, however, often fail to find any relationship between an adult insect’s choice of host–plant and offspring fitness, and in such cases, it is generally assumed that other ‘missing’ factors (e.g. predation, host–plant abundance, learning and adult feeding sites) must be contributing to overall host suitability. Here, I consider an alternative theory – that a fitness cost inherent in the olfactory mechanism could constrain the evolution of insect host selection. I begin by reviewing current knowledge of odour processing in the insect antennal lobe with the aid of a simple schematic: the aim be... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5568641 Fri, 06 Jan 2012 05:00:00 +0100 5568641 http://www.medworm.com/index.php?rid=5568644&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02441.x AbstractSpite occurs when an individual harms itself in the act of harming others. Spiteful behaviour may be more pervasive in nature than commonly thought. One of the clearest examples of spite is the costly production and release of bacteriocins, antimicrobial toxins noted for their ability to kill conspecifics. A key question is to what extent these toxins provide a fitness advantage to kin of the producer cell, especially in natural communities. Additionally, when bacteria are involved in parasitic relationships, spiteful interactions are predicted to lower bacterial densities within a host, causing a reduction in parasite‐induced virulence. Using five sympatric, field‐collected genotypes of the insect pathogen Xenorhabdus bovienii, we experimentally demonstrate that bacteriocin pr... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5568644 Wed, 04 Jan 2012 05:00:00 +0100 5568644 http://www.medworm.com/index.php?rid=5568643&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02442.x AbstractWe investigated the fitness consequences of specialization in an organism whose host choice has an immense impact on human health: the African malaria vector Anopheles gambiae s.s. We tested whether this mosquito’s specialism on humans can be attributed to the relative fitness benefits of specialist vs. generalist feeding strategies by contrasting their fecundity and survival on human‐only and mixed host diets consisting of blood meals from humans and animals. When given only one blood meal, An. gambiae s.s. survived significantly longer on human and bovine blood, than on canine or avian blood. However, when blood fed repeatedly, there was no evidence that the fitness of An. gambiae s.s. fed a human‐only diet was greater than those fed generalist diets. This suggests that t... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5568643 Wed, 04 Jan 2012 05:00:00 +0100 5568643 http://www.medworm.com/index.php?rid=5568642&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02452.x (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5568642 Wed, 04 Jan 2012 05:00:00 +0100 5568642 http://www.medworm.com/index.php?rid=5568640&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02440.x AbstractFor studies investigating trait evolution, there are at least two important questions. First, have traits under consideration influenced cladogenesis and extinction in the group? Second, how do fossil data alter inferences about trait evolution or diversification‐rate dynamics? However, relatively few studies have assessed these questions. Here, we use recently developed methods to test for trait‐dependent diversification in the New World colubrid snake tribe Lampropeltini. We also integrate data from fossil taxa into phylogenetic estimation of evolutionary parameters using a simple Monte Carlo randomization test. These analyses suggest that ecological conditions in temperate regions are tied to higher rates of cladogenesis, but that body size is not related to diversification ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5568640 Sun, 01 Jan 2012 05:00:00 +0100 5568640 http://www.medworm.com/index.php?rid=5533083&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02438.x AbstractParthenogenesis often evolves in association with hybridization, but the associated ecological consequences are poorly understood. The Australian gecko Heteronotia binoei is unusual because triploid parthenogenesis evolved through reciprocal crosses between two sexual lineages, resulting in four possible cytonuclear genotypes. In this species complex, we compared the performance of these parthenogenetic genotypes with their sexual progenitors for a suite of physiological traits (metabolic rate, thermal tolerance, locomotor performance, and in vitro activity and gene sequence divergence of a cytonuclear metabolic pathway, cytochrome C oxidase). Mass‐specific metabolic rate scaled differently with body mass for parthenogens and sexuals, while heat tolerance provided the only eviden... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5533083 Fri, 23 Dec 2011 08:19:46 +0100 5533083 http://www.medworm.com/index.php?rid=5533084&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02413.x AbstractIn the pill bug Armadillidium vulgare (Crustacea, Oniscidea), Wolbachia facilitates its spread through vertical transmission via the eggs by inducing feminization of genetic males. The spread of feminizing Wolbachia within and across populations is therefore expected to influence mitochondrial DNA (mtDNA) genetic structure by hitchhiking. To test this hypothesis, we analysed nuclear and mtDNA genetic structure, and Wolbachia prevalence in 13 populations of the pill bug host. Wolbachia prevalence (ranging from 0% to 100% of sampled females) was highly variable among populations. All three Wolbachia strains previously observed in A. vulgare were present (wVulC, wVulM and wVulP) with wVulC being the most prevalent (nine of 13 populations). The host showed a genetic structure on five ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5533084 Wed, 21 Dec 2011 05:00:00 +0100 5533084 http://www.medworm.com/index.php?rid=5533085&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02433.x AbstractThe maintenance of genetic integrity of parental populations is often explained by selection against hybrids. However, the selection agents are usually unknown. The role of environmental biotic interactions is often suspected but has rarely been demonstrated. In plants for instance, mutualism with pollinators may be involved. After verification that pollen deposition is a limiting factor for fruit set, we used an individual‐based study and a representation of pollinator colour perception to test the effects of local plant density and floral colour neighbourhood on female reproductive success in an Antirrhinum hybrid zone. In addition to flower colour and density effects, the composition of the floral neighbourhood was found to influence fruit set, suggesting that most plants were... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5533085 Tue, 20 Dec 2011 05:00:00 +0100 5533085 http://www.medworm.com/index.php?rid=5500977&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02437.x AbstractBacteria secrete a large variety of beneficial metabolites into the environment, which can be shared as public goods among producing bacteria, but also be exploited by nonproducing cheats. Here, we focus on cooperative production of iron‐chelating molecules (siderophores) in the bacterium Pseudomonas aeruginosa to study how relevant ecological factors influence selection for cheating. We designed patch‐structured metapopulations that allowed us introducing among‐patch ecological variation. We found that cheating readily evolved in uniform iron‐limited environments. This finding is explained by severe iron limitation demanding high siderophore‐production efforts, which results in high metabolic costs accruing to cooperators, and thereby facilitates the spread of cheats. In... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5500977 Wed, 14 Dec 2011 08:57:18 +0100 5500977 http://www.medworm.com/index.php?rid=5500979&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02434.x AbstractCoinfection with multiple parasite genotypes [multiplicity of infection (MOI)] creates within‐host competition and opportunities for parasite recombination and is therefore predicted to be important for both parasite and host evolution. We tested for a difference in the infectivity of viral parasites (lytic phage Φ2) and resistance of their bacterial hosts (Pseudomonas fluorescens SBW25) under both high and low MOI during coevolution in laboratory microcosms. Results show that MOI has no effect on infectivity and resistance evolution during coevolution over ∼80 generations of host growth, and this is true when the experiment is initiated with wild‐type viruses and hosts, or with viruses and hosts that have already been coevolving for ∼330 generations. This suggests that MO... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5500979 Tue, 13 Dec 2011 05:00:00 +0100 5500979 http://www.medworm.com/index.php?rid=5500978&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02436.x AbstractInteractions, antagonistic or mutualistic, can exert selection on plant traits. We explored the role of Hadena bicruris, a pollinating seed predator, as a selective agent on its host, the dioecious plant Silene latifolia. We exposed females from artificial‐selection lines (many, small flowers (SF) vs. few, large flowers (LF)) to this moth. Infestation did not differ significantly between lines, but the odds of attacked fruits aborting were higher in SF females. We partitioned selection between that caused by moth attack and that resulting from all other factors. In both lines, selection via moth attack for fewer, smaller flowers contrasted with selection via other factors for more flowers. In LF females, selection via the two components was strongest and selection via moth attack... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5500978 Tue, 13 Dec 2011 05:00:00 +0100 5500978 http://www.medworm.com/index.php?rid=5492455&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02423.x AbstractSurfacing behaviour is fundamental in the ecology of aquatic air‐breathing organisms; however, it is only in vertebrates that the evolutionary ecology of diving has been well characterized. Here, we explore the diving behaviour of dytiscid beetles, a key group of surface‐exchanging freshwater invertebrates, by comparing the dive responses of 25 taxa (Deronectes and Ilybius spp.) acclimated at two temperatures. The allometric slopes of dive responses in these dytiscids appear similar to those of vertebrate ectotherms, supporting the notion that metabolic mode shapes the evolution of diving performance. In both genera, beetles spend more time submerged than on the surface, and surface time does not vary with the temperature of acclimation. However, presumably in order to meet inc... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5492455 Thu, 08 Dec 2011 05:00:00 +0100 5492455 http://www.medworm.com/index.php?rid=5492454&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02428.x AbstractLaboratory selection for resistance to starvation has been conducted under relatively controlled conditions to investigate direct and correlated responses to artificial selection. With regard to starvation resistance, there are three physiological routes by which the trait can evolve: resource accumulation, energy conservation and starvation tolerance. A majority of energetic compounds and macromolecules including triglycerides, trehalose and other sugars, and soluble protein increased in abundance as a result of selection. Movement was additionally investigated with selected males moving less than control males and selected females exhibiting a similar response to selection. Results obtained from this study supported two of the possible evolutionary mechanisms for adaptation to st... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5492454 Thu, 08 Dec 2011 05:00:00 +0100 5492454 http://www.medworm.com/index.php?rid=5492453&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02430.x AbstractAlthough pollinators are thought to select on flower colour, few studies have experimentally decoupled effects of colour from correlated traits on pollinator visitation and pollen transfer. We combined selection analysis and phenotypic manipulations to measure the effect of petal colour on visitation and pollen export at two spatial scales in Wahlenbergia albomarginata. This species is representative of many New Zealand alpine herbs that have secondarily evolved white or pale flowers. The major pollinators, solitary bees, exerted phenotypic selection on flower size but not colour, quantified by bee vision. When presented with manipulated flowers, bees visited flowers painted blue to resemble a congener over white flowers in large, but not small, experimental arrays. Pollen export w... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5492453 Thu, 08 Dec 2011 05:00:00 +0100 5492453 http://www.medworm.com/index.php?rid=5492452&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02432.x AbstractSecondary contact zones have the potential to shed light on the mode and rate at which reproductive isolation accumulates during allopatric speciation. We investigated the population genetics of a contact zone between two highly divergent lineages of field voles (Microtus agrestis) in the Swiss Jura mountains. To shed light on the processes underlying introgression, we used maternally, paternally, and bi‐parentally inherited markers. Though the two lineages maintained a strong genetic structure, we found some hybrids and evidence of gene flow. The extent of introgression varied with the mode of inheritance, being highest for mtDNA and absent for the Y chromosome. In addition, introgression was asymmetric, occurring only from the Northern to the Southern lineage. Both patterns see... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5492452 Thu, 08 Dec 2011 05:00:00 +0100 5492452 http://www.medworm.com/index.php?rid=5492451&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02431.x AbstractGeorge Williams defined an evolutionary unit as hereditary information for which the selection bias between competing units dominates the informational decay caused by imperfect transmission. In this article, I extend Williams’ approach to show that the ratio of selection bias to transmission bias provides a unifying framework for diverse biological problems. Specific examples include Haldane and Lande's mutation–selection balance, Eigen's error threshold and quasispecies, Van Valen's clade selection, Price's multilevel formulation of group selection, Szathmáry and Demeter's evolutionary origin of primitive cells, Levin and Bull's short‐sighted evolution of HIV virulence, Frank's timescale analysis of microbial metabolism and Maynard Smith and Szathmáry's major transitions ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5492451 Thu, 01 Dec 2011 05:00:00 +0100 5492451 http://www.medworm.com/index.php?rid=5453944&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02425.x AbstractParasites represent a severe threat to social insects, which form high‐density colonies of related individuals, and selection should favour host traits that reduce infection risk. Here, using a carpenter ant (Camponotus aethiops) and a generalist insect pathogenic fungus (Metarhizium brunneum), we show that infected ants radically change their behaviour over time to reduce the risk of colony infection. Infected individuals (i) performed less social interactions than their uninfected counterparts, (ii) did not interact with brood anymore and (iii) spent most of their time outside the nest from day 3 post‐infection until death. Furthermore, infected ants displayed an increased aggressiveness towards non‐nestmates. Finally, infected ants did not alter their cuticular chemical pr... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5453944 Tue, 29 Nov 2011 08:11:24 +0100 5453944 http://www.medworm.com/index.php?rid=5453948&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02419.x We report that six fly populations subject to 112 generations of laboratory natural selection on an extremely poor larval food evolved an 18% smaller critical size (compared to six unselected control populations). Thus, even though critical size is not plastic with respect to nutrition, smaller critical size can evolve as an adaptation to nutritional stress. We also demonstrate that this reduction in critical size (rather than differences in growth rate) mediates a trade‐off in body weight that the selected populations experience on standard food, on which they show a 15–17% smaller adult body weight. This illustrates how developmental mechanisms that control life history may shape constraints and trade‐offs in life history evolution. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5453948 Mon, 28 Nov 2011 05:00:00 +0100 5453948 http://www.medworm.com/index.php?rid=5453947&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02418.x AbstractNorth American Enallagma damselflies radiated during the Pleistocene, and species differ mainly by reproductive structures. Although morphologically very different, Enallagma hageni and Enallagma ebrium are genetically very similar. Partitioning of genetic variation (AFLP), isolation by distance and clustering analyses indicate that these morphospecies are locally differentiated genetically. Spatial analyses show that they are rarely sympatric at local sites, and their distributions form a mosaic of patches where one is clearly dominant over hundreds of square kilometers. However, these morphospecies are also not genetically more similar when they are sympatric, indicating that hybridization is probably not occurring. Given that these morphospecies are ecologically equivalent, stro... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5453947 Mon, 28 Nov 2011 05:00:00 +0100 5453947 http://www.medworm.com/index.php?rid=5453946&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02420.x We present a phylogenetic comparative study assessing the evolutionary determinants of egg size in the moth family Geometridae. These moths were found to show a strong negative allometric relationship between egg size and maternal body size. Using recently developed comparative methods based on an Ornstein‐Uhlenbeck process, we show that maternal body size explains over half the variation in egg size. However, other determinants are less clear: ecological factors, previously hypothesized to affect egg size, were not found to have a considerable influence in the Geometridae. The limited role of such third factors suggests a direct causal link between egg size and body size rather than an indirect correlation mediated by some ecological factors. Notably, no large geometrid species lay smal... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5453946 Mon, 28 Nov 2011 05:00:00 +0100 5453946 http://www.medworm.com/index.php?rid=5453945&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02424.x AbstractHybrid incompatibilities, measured as mortality and sterility, are caused by the disruption of gene interactions. They are important post‐zygotic isolation barriers to species hybridization, and much effort is put into the discovery of the genes underlying these incompatibilities. In hybridization studies of the haplodiploid parasitic wasp genus Nasonia, genic incompatibilities have been shown to affect mortality and sterility. The genomic regions associated with mortality have been found to depend on the cytotype of the hybrids and thus suggest cytonuclear incompatibilities. As environmental conditions can affect gene expression and gene interaction, we here investigate the effect of developmental temperature on sterility and mortality in Nasonia hybrids. Results show that extre... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5453945 Mon, 28 Nov 2011 05:00:00 +0100 5453945 http://www.medworm.com/index.php?rid=5447529&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02427.x Abstract Theropod dinosaurs, an iconic clade of fossil species including Tyrannosaurus and Velociraptor, developed a great diversity of body size, skull form and feeding habits over their 160+ million year evolutionary history. Here, we utilize geometric morphometrics to study broad patterns in theropod skull shape variation and compare the distribution of taxa in cranial morphospace (form) to both phylogeny and quantitative metrics of biting behaviour (function). We find that theropod skulls primarily differ in relative anteroposterior length and snout depth and to a lesser extent in orbit size and depth of the cheek region, and oviraptorosaurs deviate most strongly from the “typical” and ancestral theropod morphologies. Noncarnivorous taxa generally fall out in distinct regions of mo... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5447529 Sat, 26 Nov 2011 08:37:18 +0100 5447529 http://www.medworm.com/index.php?rid=5447531&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02426.x AbstractComparing niche divergence among closely related taxa can yield important insights into the ecological distinctiveness of genetically similar forms, and identify the processes that are responsible for diversification in such organisms. Here, we apply newly developed techniques for analysing niche divergence to assess how ecologically distinct a group of closely related rattlesnakes (Sistrurus sp.) are and to explore the role that niche divergence may have played in their diversification. We find that all taxa even the most recently evolved subspecies (approximately 100 000 years old) are now ecologically distinct, implying a role for ecology in the diversification process. Statistical analysis based on comparisons with null models show that niche divergence between forms is mor... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5447531 Thu, 24 Nov 2011 05:00:00 +0100 5447531 http://www.medworm.com/index.php?rid=5447534&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02422.x Abstract  Ever since Eldredge and Gould proposed their model of punctuated equilibria, evolutionary biologists have debated how often this model is the best description of nature and how important it is compared to the more gradual models of evolution expected from natural selection and the neo‐Darwinian paradigm. Recently, Cubo proposed a method to test whether morphological data in extant ratites are more compatible with a gradual or with a speciational model (close to the punctuated equilibrium model). As shown by our simulations, a new method to test the mode of evolution of characters (involving regression of standardized contrasts on their expected standard deviation) is easier to implement and more powerful than the previously proposed method, but the Mesquite module comet (aime... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5447534 Wed, 23 Nov 2011 05:00:00 +0100 5447534 http://www.medworm.com/index.php?rid=5447533&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02429.x Abstract We test for effects of thermal stress applied to pupal flies from Noumea (New Caledonia) and Taipei (Taiwan) on developmental instability (DI) in the male sex comb of Drosophila bipectinata, as well as on pre‐adult survivorship and adult body size. The temperature treatments were Low (25 °C), High (29 °C) and Variable (18 h at 29 °C, 6 h at 34 °C). Although the Variable treatment reduced survivorship and body size, absolute comb size and fluctuating asymmetry generally were invariant across treatments. In contrast, comb phenodeviance increased with stress in both populations. Phenodeviance in one comb segment (C2) increased sharply with stress, whereas phenodeviance in a second major segment (C1) also increased with stress but only in Noumea flies. A major conclu... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5447533 Wed, 23 Nov 2011 05:00:00 +0100 5447533 http://www.medworm.com/index.php?rid=5447532&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02421.x AbstractIn a model based on the wasp family Vespidae, the origin of worker behaviour, which constitutes the eusociality threshold, is not based on relatedness, therefore the origin of eusociality does not depend on inclusive fitness, and workers at the eusociality threshold are not altruistic. Instead, incipient workers and queens behave selfishly and are subject to direct natural selection. Beyond the eusociality threshold, relatedness enables ‘soft inheritance’ as the framework for initial adaptations of eusociality. At the threshold of irreversibility, queen and worker castes become fixed in advanced eusociality. Transitions from solitary to facultative, facultative to primitive, and primitive to advanced eusociality occur via exaptation, phenotypic accommodation and genetic assimil... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5447532 Wed, 23 Nov 2011 05:00:00 +0100 5447532 http://www.medworm.com/index.php?rid=5417338&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02417.x We examined published phylogenetic analyses, derived from genetic sequence data, to generate two estimates of the age of species: (i) the oldest intraspecific diversification event within each taxon and (ii) the inferred timing of the split between two sister species. The timing of splits between species shows the same pattern as splits within species, and thus may be due to climatically driven cladogenic and extinction events or may be an artefact of differing levels of taxonomic knowledge about the fauna. Current rates of species descriptions suggest that many more taxa remain to be described in the Southern Hemisphere than the Northern Hemisphere; for that bias to fully explain our results on species age differences, the proportion of undescribed Southern taxa would need to be ≥ 12%... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417338 Thu, 17 Nov 2011 22:21:15 +0100 5417338 http://www.medworm.com/index.php?rid=5417342&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02411.x AbstractSocial networks describe the pattern of intraspecific interactions within a population. An individual’s position in a social network often is expected to influence its fitness, but only a few studies have examined this relationship in natural populations. We investigated the fitness consequences of network position in a wild beetle population. Copulation success of male beetles positively covaried with strength (a measure of network centrality) and negatively covaried with clustering coefficient (CC) (a measure of cliquishness). Further analysis using mediation path models suggested that the activity level of individuals drove the relationships between strength and fitness almost entirely. In contrast, selection on CC was not explained by individual behaviours. Although our data ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417342 Thu, 17 Nov 2011 05:00:00 +0100 5417342 http://www.medworm.com/index.php?rid=5417341&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02414.x AbstractVery little is known about the nature and strength of reproductive isolation (RI) in Quercus species, despite extensive research on the estimation and evolutionary significance of hybridization rates. We characterized postmating pre‐ and postzygotic RI between two hybridizing oak species, Quercus robur and Quercus petraea, using a large set of controlled crosses between different genotypes. Various traits potentially associated with reproductive barriers were quantified at several life history stages, from pollen–pistil interactions to seed set and progeny fitness‐related traits. Results indicate strong intrinsic postmating prezygotic barriers, with significant barriers also at the postzygotic level, but relatively weaker extrinsic barriers on early hybrid fitness measures as... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417341 Thu, 17 Nov 2011 05:00:00 +0100 5417341 http://www.medworm.com/index.php?rid=5417340&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02415.x AbstractStudies of sexual selection in speciation have traditionally focused on mate preference, with less attention given to traits that act between copulation and fertilization. However, recent work suggests that post‐mating prezygotic barriers may play an important role in speciation. Here, we evaluate the role of such barriers in the field crickets, Gryllus firmus and Gryllus pennsylvanicus. Gryllus pennsylvanicus females mated with G. firmus males produce viable, fertile offspring, but when housed with both species produce offspring sired primarily by conspecifics. We evaluate patterns of sperm utilization in doubly mated G. pennsylvanicus females and find no evidence for conspecific sperm precedence. The reciprocal cross (G. firmus female × G. pennsylvanicus male) produces... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417340 Thu, 17 Nov 2011 05:00:00 +0100 5417340 http://www.medworm.com/index.php?rid=5417339&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02416.x AbstractSpatial abiotic heterogeneity can result in divergent selection, hence might increase the magnitude of host–parasite local adaptation (the mean difference in fitness of sympatric vs. allopatric host–parasite combinations). We explicitly tested this hypothesis by measuring local adaptation in experimentally coevolved populations of bacteria and viruses evolved in the same or different nutrient media. Consistent with previous work, we found that mean levels of evolved phage infectivity and bacteria resistance varied with nutrient concentration, with maximal levels at nutrient concentrations that supported the greatest densities of bacteria. Despite this variation in evolved mean infectivity and resistance between treatments, we found that parasite local adaptation was greatly inc... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417339 Thu, 17 Nov 2011 05:00:00 +0100 5417339 http://www.medworm.com/index.php?rid=5417343&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02412.x AbstractWithin‐individual consistency and among‐individual heterogeneity in fitness are prerequisites for selection to take place. Within‐individual variation in productivity between years, however, can vary considerably, especially when organisms become older and more experienced. We examine individual consistency in annual productivity, the covariation between survival and annual productivity, and the sources of variation in annual productivity, while accounting for advancing age, to test the individual‐quality and resource‐allocation life‐history theory hypotheses. We use long‐term data from a pedigreed, wild population of house sparrows. Within‐individual annual productivity first increased and later decreased with age, but there were no selective mortality due to indiv... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5417343 Mon, 14 Nov 2011 05:00:00 +0100 5417343 http://www.medworm.com/index.php?rid=5396621&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02407.x In conclusion, females displaying alternative melanic phenotypes bred in habitats providing them with the highest fitness benefits. Although small in magnitude, matching habitat selection and local adaptation may help maintain variation in pheomelanin coloration in the barn owl. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5396621 Wed, 09 Nov 2011 05:00:00 +0100 5396621 http://www.medworm.com/index.php?rid=5396620&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02409.x AbstractHybridization in animals is a much more common phenomenon as previously thought and may have profound implications for speciation research. The cichlid genus Steatocranus (Teleostei: Cichlidae), a close relative to members of the East African cichlid radiations, radiated under riverine conditions in the lower Congo rapids and produced a small species flock. Previous phylogenetic analyses suggested that hybridization occurred and contributed to speciation in this genus. A re‐analysis of an already published 2000 loci‐AFLP data set explicitly testing for patterns of ancient gene flow provided strong evidence for a highly reticulate phylogenetic history of the genus. We provide, to our knowledge, the first example of a complex reticulate network in vertebrates, including multiple ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5396620 Wed, 09 Nov 2011 05:00:00 +0100 5396620 http://www.medworm.com/index.php?rid=5396619&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02410.x AbstractThe structure of compound leaves provides flexibility for morphological change by variation in the shapes, sizes and arrangement of leaflets. Here, we conduct a multilevel analysis of shape variation in compound leaves to explore the developmental plasticity and evolutionary potential that are the basis of diversification in leaf shape. We use the methods of geometric morphometrics to study the shapes of individual leaflets and whole leaves in 20 taxa of Potentilla (sensu lato). A newly developed test based on the bootstrap approach suggests that uncertainty in the molecular phylogeny precludes firm conclusions whether there is a phylogenetic signal in the data on leaf shape. For variation among taxa, variation within taxa, as well as fluctuating asymmetry, there is evidence of str... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5396619 Tue, 01 Nov 2011 04:00:00 +0100 5396619 http://www.medworm.com/index.php?rid=5355192&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02406.x AbstractCarnivorous plants of the genus Nepenthes have evolved a striking diversity of pitcher traps that rely on specialized slippery surfaces for prey capture. With a comparative study of trap morphology, we show that Nepenthes pitcher plants have evolved specific adaptations for the use of either one of two distinct trapping mechanisms: slippery wax crystals on the inner pitcher wall and ‘insect aquaplaning’ on the wet upper rim (peristome). Species without wax crystals had wider peristomes with a longer inward slope. Ancestral state reconstructions identified wax crystal layers and narrow, symmetrical peristomes as ancestral, indicating that wax crystals have been reduced or lost multiple times independently. Our results complement recent reports of nutrient source specializations ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355192 Fri, 28 Oct 2011 00:22:53 +0100 5355192 http://www.medworm.com/index.php?rid=5355194&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02399.x AbstractNumerous studies have shown positive associations between ornaments and condition, as predicted by indicator models of sexual selection. However, this idea is continuously challenged by opposite results, which reveal our lack of full understanding of how sexual selection works. Environmental heterogeneity may explain such inconsistencies, but valid field tests of this idea are currently lacking. We first analysed the relationship between condition and ornament expression from nine populations over 7 years in a wild bird, the red grouse Lagopus lagopus scoticus. We then manipulated male aggressiveness at the population level by means of testosterone implants in a replicated field experiment. We found that the relationship between condition and ornamentation varied greatly between ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355194 Tue, 25 Oct 2011 04:00:00 +0100 5355194 http://www.medworm.com/index.php?rid=5355193&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02405.x AbstractIn host–symbiont interactions, the genes of both host and symbiont can influence phenotypic traits. In the context of a conflict of interest, fitness‐related traits are subjected to opposing selective pressures in the genomes of the partners. In the Drosophila parasitoid Leptopilina boulardi, females usually avoid laying eggs into already parasitized larvae. However, when infected by the virus LbFV, they readily lay additional eggs into parasitized larvae. Inducing superparasitism allows the virus to colonize uninfected parasitoid lineages but is usually maladaptive for the parasitoid. We tested for the presence of resistance genes to this behavioural manipulation in the parasitoid genotype by sampling 30 lines from five populations with contrasting viral prevalence, after infe... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355193 Tue, 25 Oct 2011 04:00:00 +0100 5355193 http://www.medworm.com/index.php?rid=5355198&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02401.x In this study, we experimentally explored cross‐host correlations and performance among families in four species (two generalist and two specialist) of leaf beetles (Cephaloleia spp.) that are currently expanding their diets from native to exotic plants. All four species displayed similar responses in body size, developmental rates and mortality rates to experimentally controlled diets. When raised on novel hosts, body size of larvae, pupae and adults were reduced. Development times were longer, and larval mortality was higher on novel hosts. Genotype × host–plant interactions were not detected for most traits. All significant cross‐host correlations were positive. These results indicate very different ecological and evolutionary dynamics than those predicted by the ‘Jack of a... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355198 Mon, 24 Oct 2011 04:00:00 +0100 5355198 http://www.medworm.com/index.php?rid=5355197&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02402.x AbstractStudying resource specialization at the individual level can identify factors constraining the evolution of generalism. We quantified genotypic and phenotypic variability among infective stages of 20 clones of the parasitic trematode Maritrema novaezealandensis and measured their infection success and post‐infection fitness (growth, egg output) in several crabs and amphipods. First, different clones varied in their infection success of different crustaceans. Second, neither genetic nor phenotypic traits had consistent effects on infection success across all host species. Although the results suggest a relationship between infection success and phenotypic variability, phenotypically variable clones were not better at infecting more host species than less variable ones. Third, gene... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355197 Mon, 24 Oct 2011 04:00:00 +0100 5355197 http://www.medworm.com/index.php?rid=5355196&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02403.x AbstractTheory predicts that the evolution of phenotypic plasticity depends upon cues that indicate environmental change. Predators typically induce plastic responses in prey. However, variation among populations of predators alters the frequency of predation and, possibly, the evolution of plasticity. We compared responses to predator cues in Daphnia ambigua from lakes where alewife (Alosa pseudoharengus) either do (anadromous) or do not (landlocked) migrate between marine and freshwater. In ‘anadromous’ lakes, Daphnia are abundant each spring but eliminated by alewives in summer, whereas Daphnia are constantly under the threat of predation in ‘landlocked’ lakes. Daphnia from ‘anadromous’ lakes grew faster, matured earlier and larger, produced more offspring and invested more ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355196 Mon, 24 Oct 2011 04:00:00 +0100 5355196 http://www.medworm.com/index.php?rid=5355195&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02404.x AbstractIntroduced species represent opportunities to observe evolution over contemporary time scales, and as exotics encounter new environments, adaptive responses can occur, potentially contributing to invasion. Here, we compare 22 native North American populations and 12 introduced European populations of common ragweed (Ambrosia artemisiifolia) in five common gardens (control, herbivory, light stress, nutrient stress and drought). We found evidence for improved growth and reproduction of the introduced populations in most environments, particularly in the light stress. However, under drought conditions, the introduced plants experienced more rapid wilting and mortality than their native counterparts, evidence consistent with a life‐history trade‐off between rapid growth and drought... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5355195 Mon, 24 Oct 2011 04:00:00 +0100 5355195 http://www.medworm.com/index.php?rid=5321402&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02400.x In this study, we examine the effect of male inbreeding status (inbreeding coefficient f = 0.25 vs. f = 0) on the fecundity, adult longevity and the fate of eggs produced by outbred females in the seed‐feeding beetle, Callosobruchus maculatus. Females mated to inbred males were less likely to lay eggs. Of those that laid eggs, females mated to inbred males laid 6–12% fewer eggs. Females mated to inbred males lived on average 5.4% longer than did females mated to outbred males, but this effect disappeared when lifetime fecundity was used as a covariate in the analysis. There was no effect of male inbreeding status on the proportion of a female’s eggs that developed or hatched, and no evidence that inbred males produced smaller nuptial gifts. However, ejaculates of inbred males... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5321402 Sun, 16 Oct 2011 10:15:43 +0100 5321402 http://www.medworm.com/index.php?rid=5310584&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02391.x AbstractDiversification rates within four conspicuous coral reef fish families (Labridae, Chaetodontidae, Pomacentridae and Apogonidae) were estimated using Bayesian inference. Lineage through time plots revealed a possible late Eocene/early Oligocene cryptic extinction event coinciding with the collapse of the ancestral Tethyan/Arabian hotspot. Rates of diversification analysis revealed elevated cladogenesis in all families in the Oligocene/Miocene. Throughout the Miocene, lineages with a high percentage of coral reef–associated taxa display significantly higher net diversification rates than expected. The development of a complex mosaic of reef habitats in the Indo‐Australian Archipelago (IAA) during the Oligocene/Miocene appears to have been a significant driver of cladogenesis. Pat... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5310584 Thu, 13 Oct 2011 09:11:44 +0100 5310584 http://www.medworm.com/index.php?rid=5321404&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02397.x AbstractThe genetic structure of social insect populations is influenced by their social organization and dispersal modes. The ant Hypoponera opacior shows diverse reproductive behaviours with regular cycles of outbreeding via winged sexuals and inbreeding via within‐nest mating wingless sexuals that reproduce by budding. This unusual life cycle should be reflected in the genetic population structure, and we studied this on different scales using microsatellites. On a macrogeographic scale, populations were considerably structured and migration rates within the Chiricahuas were higher than those in between mountain ranges. On a local scale, our analyses revealed population viscosity through dependent colony foundation and a high genetic diversity with a multicolonial structure. The latte... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5321404 Thu, 13 Oct 2011 04:00:00 +0100 5321404 http://www.medworm.com/index.php?rid=5321403&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02398.x AbstractThe evolutionary foundations of helping among nonkin in humans have been the object of intense debates in the past decades. One thesis has had a prominent influence in this debate: the suggestion that genuine altruism, strictly defined as a form of help that comes at a net fitness cost for the benefactor, might have evolved owing to cultural transmission. The gene–culture coevolution literature is wont to claim that cultural evolution changes the selective pressures that normally act to limit the emergence of altruistic behaviours. This paper aims to recall, however, that cultural transmission yields altruism only to the extent that it relies on maladaptive mechanisms, such as conformist imitation and (in some cases) payoff‐biased transmission. This point is sometimes obscured ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5321403 Thu, 13 Oct 2011 04:00:00 +0100 5321403 http://www.medworm.com/index.php?rid=5268447&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02396.x This study suggests a model of how simple heterochronic perturbations can produce phenotypic variation, and thus potential for further evolutionary change, even within a strictly constrained developmental pathway. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268447 Fri, 30 Sep 2011 09:39:34 +0100 5268447 http://www.medworm.com/index.php?rid=5268453&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02381.x AbstractFlapping flight has evolved independently in three vertebrate clades: pterosaurs, birds and bats. Each clade has a unique flight mechanism involving different elements of the forelimb. Here, patterns of limb integration are examined using partial correlation analysis within species and matrix correlation analysis across species to test whether the evolution of flapping flight has involved developmental dissociation of the serial homologues in the fore‐ and hind limb in each clade. Our sample included seven species of birds, six species of bats, and three species of pterosaurs for which sufficient sample sizes were available. Our results showed that, in contrast to results previously reported for quadrupedal mammals, none of the three clades demonstrated significant integration be... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268453 Thu, 29 Sep 2011 04:00:00 +0100 5268453 http://www.medworm.com/index.php?rid=5268452&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02384.x AbstractChanges in diversification patterns estimated from phylogenetic trees are an important source of information about the dynamics of evolution. To study the diversification of mammals, we reconstructed phylogenetic trees of 29 families and fitted both constant‐rate and variable‐rate models of diversification. In addition, we investigated the effect of clock models and phylogenetic reconstruction problems on diversification analyses. We observed, first, that none of the families increased its diversification rate during the last few million years, including the Pleistocene. Furthermore, we detected a decrease in diversification that, after application of different tests, was significant only for a minority of families. However, when diversification variation was analysed in a comb... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268452 Thu, 29 Sep 2011 04:00:00 +0100 5268452 http://www.medworm.com/index.php?rid=5268451&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02392.x AbstractAlthough verbal theories of speciation consider landscape changes, ecological speciation is usually modelled in a fixed geographical arrangement. Yet landscape changes occur, at different spatio‐temporal scales, due to geological, climatic or ecological processes, and these changes result in repeated divisions and reconnections of populations. We examine the effect of such landscape dynamics on speciation. We use a stochastic, sexual population model with polygenic inheritance, embedded in a landscape dynamics model (allopatry–sympatry oscillations). We show that, under stabilizing selection, allopatry easily generates diversity, but species coexistence is evolutionarily unsustainable. Allopatry produces refuges whose persistence depends on the characteristic time scales of the... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268451 Thu, 29 Sep 2011 04:00:00 +0100 5268451 http://www.medworm.com/index.php?rid=5268450&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02393.x AbstractPhenotypic plasticity can be important for local adaptation, because it enables individuals to survive in a novel environment until genetic changes have been accumulated by genetic accommodation. By analysing the relationship between development rate and growth rate, it can be determined whether plasticity in life‐history traits is caused by changed physiology or behaviour. We extended this to examine whether plasticity had been aiding local adaptation, by investigating whether the plastic response had been fixed in locally adapted populations. Tadpoles from island populations of Rana temporaria, locally adapted to different pool‐drying regimes, were monitored in a common garden. Individual differences in development rate were caused by different foraging efficiency. However, d... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268450 Thu, 29 Sep 2011 04:00:00 +0100 5268450 http://www.medworm.com/index.php?rid=5268449&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02394.x AbstractWe genetically characterize an unusual hybrid incompatibility phenotype manifest in F1 offspring of crosses between two populations of Tribolium castaneum. Hybrid larvae cease development at the third larval instar, persisting as ‘perpetually immature larvae’ thereafter. Although unable to produce viable adult hybrid offspring with one another, each population produces abundant, fertile hybrids with other populations, indicating a recent origin of the incompatibility and facilitating genetic studies. We mapped the paternal component of the hybrid phenotype to a single region, which exhibits two characteristics common to hybrid incompatibility: marker transmission ratio distortion within crosses and elevated genetic divergence between populations. The incompatible variation and ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268449 Thu, 29 Sep 2011 04:00:00 +0100 5268449 http://www.medworm.com/index.php?rid=5268448&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02395.x AbstractCaviomorphs are a clade of South American rodents recorded at least since the early Oligocene (> 31.5 Ma) that exhibit ample eco‐morphological variation. It has been proposed that phylogenetic structure is more important than ecological factors for understanding mandibular shape variation in this clade. This was interpreted as a result of the long‐standing evolutionary history of caviomorphs and the early divergence of major lineages. In this work, we test this hypothesis through the analysis of morphological variation in the mandible of living and extinct species and compare this information with that obtained through comparative phylogenetic analyses. Our results support the hypothesis of early origin of mandibular variation; moreover, they suggest the conservation of ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268448 Thu, 29 Sep 2011 04:00:00 +0100 5268448 http://www.medworm.com/index.php?rid=5268459&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02380.x AbstractIn gynodioecious species, in which hermaphroditic and female plants co‐occur, the maintenance of sexual polymorphism relies on the genetic determination of sex and on the relative fitness of the different phenotypes. Flower production, components of male fitness (pollen quantity and pollen quality) and female fitness (fruit and seed set) were measured in gynodioecious Beta vulgaris spp. maritima, in which sex is determined by interactions between cytoplasmic male sterility (CMS) genes and nuclear restorers of male fertility. The results suggested that (i) female had a marginal advantage over hermaphrodites in terms of flower production only, (ii) restored CMS hermaphrodites (carrying both CMS genes and nuclear restorers) suffered a slight decrease in fruit production compared to ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268459 Wed, 28 Sep 2011 04:00:00 +0100 5268459 http://www.medworm.com/index.php?rid=5268458&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02385.x AbstractIn most plural‐breeding mammals, female group members are matrilineal relatives but, in a small number of species, all adult females are immigrants who are seldom closely related to each other. Some explanations of contrasts in female philopatry suggest that these differences are a consequence of variation in resource distribution and feeding competition, whereas others argue that they reflect variation in the risk of close inbreeding to philopatric females. However, neither explanation has been tested against quantitative comparisons. Here, we use quantitative comparisons and phylogenetic reconstructions to show that contrasts in female philopatry in plural breeders are associated with the risk that a female’s father is reproductively active in her group when she starts to bre... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268458 Wed, 28 Sep 2011 04:00:00 +0100 5268458 http://www.medworm.com/index.php?rid=5268457&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02387.x This study further suggests that the allometric elevation is more variable than the allometric slope. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268457 Wed, 28 Sep 2011 04:00:00 +0100 5268457 http://www.medworm.com/index.php?rid=5268456&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02388.x AbstractDetecting adaptation involves comparing the performance of populations evolving in different environments. This detection may be confounded by effects due to the environment experienced by organisms prior to the test. We tested whether such confounding effects occur, using spider‐mite selection lines on two novel hosts and one ancestral host, after 15 generations of selection. Mites were either sampled directly from the selection lines or subjected to a common juvenile or to a common maternal environment, mimicking the most frequent environmental manipulations. These environments strongly affected all life‐history traits. Moreover, the detection of adaptation and correlated responses on the ancestral host was inconsistent among environments in almost 20% of the cases. Indeed, w... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268456 Wed, 28 Sep 2011 04:00:00 +0100 5268456 http://www.medworm.com/index.php?rid=5268455&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02389.x AbstractSexual selection on male coloration has been implicated in the evolution of colourful species flocks of East African cichlid fish. During adaptive radiations, animals diverge in multiple phenotypic traits, but the role of physiology has received limited attention. Here, we report how divergence in physiology may contribute to the stable coexistence of two hybridizing incipient species of cichlid fish from Lake Victoria. Males of Pundamilia nyererei (males are red) tend to defeat those of Pundamilia pundamilia (males are blue), yet the two sibling species coexist in nature. It has been suggested that red males bear a physiological cost that might offset their dominance advantage. We tested the hypothesis that the two species differ in oxidative stress levels and immune function and ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268455 Wed, 28 Sep 2011 04:00:00 +0100 5268455 http://www.medworm.com/index.php?rid=5268454&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02390.x AbstractIn diploids, F1 offspring performance is expected to increase with increasing genetic dissimilarity between the parents until an optimum is reached because outbreeding mitigates inbreeding depression and maximizes heterosis. However, many flowering plant species are derived through allopolyploidization, i.e. interspecific hybridization with genome doubling. This mode of plant speciation can be expected to considerably alter the consequences of inbreeding and outbreeding. We investigated the F1 fitness consequences of mating over a range of (genetic) distances in the allohexaploid plant species Geum urbanum. Offspring was raised under controlled conditions (632 plants). The performance of outcrossed progeny was not significantly better than that of their selfed half‐siblings and d... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5268454 Wed, 28 Sep 2011 04:00:00 +0100 5268454 http://www.medworm.com/index.php?rid=5246081&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02373.x AbstractIn classical evolutionary theory, genetic variation provides the source of heritable phenotypic variation on which natural selection acts. Against this classical view, several theories have emphasized that developmental variability and learning enhance nonheritable phenotypic variation, which in turn can accelerate evolutionary response. In this paper, I show how developmental variability alters evolutionary dynamics by smoothing the landscape that relates genotype to fitness. In a fitness landscape with multiple peaks and valleys, developmental variability can smooth the landscape to provide a directly increasing path of fitness to the highest peak. Developmental variability also allows initial survival of a genotype in response to novel or extreme environmental challenge, providi... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5246081 Fri, 23 Sep 2011 08:25:38 +0100 5246081 http://www.medworm.com/index.php?rid=5246082&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02378.x AbstractMany studies have analysed how variability in reproductive success affects fitness. However, each study tends to focus on a particular problem, leaving unclear the overall structure of variability in populations. This fractured conceptual framework often causes particular applications to be incomplete or improperly analysed. In this article, I present a concise introduction to the two key aspects of the theory. First, all measures of fitness ultimately arise from the relative comparison of the reproductive success of individuals or genotypes with the average reproductive success in the population. That relative measure creates a diminishing relation between reproductive success and fitness. Diminishing returns reduce fitness in proportion to variability in reproductive success. The... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5246082 Wed, 21 Sep 2011 04:00:00 +0100 5246082 http://www.medworm.com/index.php?rid=5233173&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02377.x AbstractBacterial biofilms are particularly resistant to a wide variety of antimicrobial compounds. Their persistence in the face of antibiotic therapies causes significant problems in the treatment of infectious diseases. Seldom have evolutionary processes like genetic drift and mutation been invoked to explain how resistance to antibiotics emerges in biofilms, and we lack a simple and tractable model for the genetic and phenotypic diversification that occurs in bacterial biofilms. Here, we introduce the ‘onion model’, a simple neutral evolutionary model for phenotypic diversification in biofilms. We explore its properties and show that the model produces patterns of diversity that are qualitatively similar to observed patterns of phenotypic diversity in biofilms. We suggest that mode... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5233173 Mon, 19 Sep 2011 22:01:09 +0100 5233173 http://www.medworm.com/index.php?rid=5217594&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02382.x AbstractBiogeographic boundaries are the meeting zone of broadly distributed faunas, or the actual cause of a faunal break. In the latter case, closely related sister species should be found across such a boundary. To achieve such a situation, preliminary stages are expected, where phylogeographic breaks followed by genetic cryptic speciation would be observed. Biogeographic boundaries, in the Cape Point/Cape Agulhas region of southern Africa, offer an ideal system to test such predictions. Here, we studied two intertidal clinid fish species that are endemic to southern Africa, Clinus superciliosus (n = 127) and Muraenoclinus dorsalis (n = 114). Using mitochondrial control region, 16S rRNA, 12S rRNA and NADH2 genes and the nuclear rhodopsin and the first intron of the S7 ribosomal ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5217594 Wed, 14 Sep 2011 09:08:29 +0100 5217594 http://www.medworm.com/index.php?rid=5203955&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02379.x AbstractTemporal resource fluctuations could affect the strength of antagonistic coevolution through population dynamics and costs of adaptation. We studied this by coevolving the prey bacterium Serratia marcescens with the predatory protozoa Tetrahymena thermophila in constant and pulsed‐resource environments for approximately 1300 prey generations. Consistent with arms race theory, the prey evolved to be more defended, whereas the predator evolved to be more efficient in consuming the bacteria. Coevolutionary adaptations were costly in terms of reduced prey growth in resource‐limited conditions and less efficient predator growth on nonliving resource medium. However, no differences in mean coevolutionary changes or adaptive costs were observed between environments, even though resour... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203955 Thu, 08 Sep 2011 04:00:00 +0100 5203955 http://www.medworm.com/index.php?rid=5203954&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02383.x AbstractIn viviparous species, a conflict over maternal resource allocation may arise between mothers and embryos, between siblings, and between maternal and paternal genes within an embryo due to relatedness asymmetries. We performed two experiments to study the effects of polyandry and brood relatedness on offspring growth in a placental fish (Heterandria formosa). Polyandry was beneficial as it increased the probability of pregnancy, possibly to avoid genetic incompatibility. However, females mated to four males produced offspring that had a longer maturation time than those of monandrous females. When within‐brood relatedness was manipulated, the size of the newborn offspring decreased with time in low‐relatedness treatment, whereas in highly related broods, offspring size was cons... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203954 Thu, 08 Sep 2011 04:00:00 +0100 5203954 http://www.medworm.com/index.php?rid=5203958&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02374.x AbstractOxidative stress is considered to act as a universal physiological constraint in life‐history evolution of animals. This should be of interest for extra‐pair paternity behaviour, and we tested here the prediction that offspring arising from extra‐pair matings of female great tits show higher resistance to oxidative stress than within‐pair offspring. Resistance to oxidative stress, measured as the whole blood resistance to a controlled free‐radical attack, was significantly higher for extra‐pair offspring as predicted although these were not heavier or in better body condition than within‐pair offspring. Since resistance to oxidative stress has been suggested to enhance survival and reproductive rates, extra‐pair offspring with superior resistance to oxidative stress... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203958 Wed, 07 Sep 2011 04:00:00 +0100 5203958 http://www.medworm.com/index.php?rid=5203957&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02375.x AbstractTheoretical and empirical studies indicate that exploitation is a possible driver of exploiter and victim diversification. However, there are many factors which could promote and limit this diversification process. Using a spatially explicit individual‐based model, where an exploiter’s success depends on matching between its own and a victim’s continuous trait, we simulate local communities of victims and exploiters. We investigate how exploiter mobility (searching ability and movement strategies) can influence diversification of victims. We find that if victim traits are under intermediate intensity of stabilizing selection, disruptive selection exerted by exploiters can indeed lead to diversification in victim population and the victim trait distribution can split into two ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203957 Wed, 07 Sep 2011 04:00:00 +0100 5203957 http://www.medworm.com/index.php?rid=5203956&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02376.x AbstractAlthough theory established the necessary conditions for diversification in temporally heterogeneous environments, empirical evidence remains controversial. One possible explanation is the difficulty of designing experiments including the relevant range of temporal grains and the appropriate environmental trade‐offs. Here, we experimentally explore the impact of the grain on the diversification of the bacterium Pseudomonas fluorescens SBW25 in a temporally fluctuating environment by including 20 different pairs of environments and four temporal grains. In general, higher levels of diversity were observed at intermediate temporal grains. This resulted in part from the enhanced capacity of disruptive selection to generate negative genotypic correlations in performance at intermedia... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203956 Wed, 07 Sep 2011 04:00:00 +0100 5203956 http://www.medworm.com/index.php?rid=5203953&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02386.x AbstractCommunication is central to most interactions between organisms. There is currently considerable controversy about the evolution, function and even about the most basic definition of communication. The controversy is linked to definitional ambiguities and disagreements. Here we discuss how some recent disagreements can be resolved and offer a clear set of definitions. Central to our approach is a definition of communication as being a trade between one organism (the informer) and another (the perceiver). The informer exerts influence on the perceiver through the communication process, and the perceiver experiences a change in its informational state (that is, gains information) as a consequence of detecting the communication. We define both influence and information explicitly and ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5203953 Thu, 01 Sep 2011 04:00:00 +0100 5203953 http://www.medworm.com/index.php?rid=5155440&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02357.x AbstractThe utility of traits involved in resource exploitation is a central criterion for the adaptive character of radiations. Here, we test for differentiation in morphology, jaw mechanics and nutrition among species and sexes of Lake Matano’s sympatric ‘roundfin’ sailfin silversides. The three incipient fish species differ significant in several candidate traits for adaptation following ecological selection pressure, corresponding to contrasting jaw mechanics and distinct patterns in food resource use. These findings are consistent with functional adaptation and suggest divergence following alternative modes of feeding specialization. Further, intersexual resource partitioning and corresponding adaptation in jaw mechanics is evident in two of the three incipient species, demonstr... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155440 Thu, 25 Aug 2011 07:12:25 +0100 5155440 http://www.medworm.com/index.php?rid=5155445&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02368.x AbstractHox genes are recognized for their explanatory power of bilateral development. However, relatively little is known about natural variation in, and the evolutionary dynamics of, Hox genes within wild populations. Utilizing a natural population of sand lizards (Lacerta agilis), we screened HoxA13 for genetic variation and an association with incidence of offspring malformations. We found significant effects of parental genetic similarity and offspring sex, and their interaction, on risk of hatching malformed as an offspring. We also found within population genetic variation in HoxA13, and identified a significant effect of a three‐way interaction among Hox genotype, parental genetic similarity, and offspring sex on the risk of hatching malformation. Since malformed offspring in thi... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155445 Mon, 22 Aug 2011 23:00:00 +0100 5155445 http://www.medworm.com/index.php?rid=5155444&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02369.x AbstractMalaria infections normally consist of more than one clonally replicating lineage. Within‐host interactions between sensitive and resistant parasites can have profound effects on the evolution of drug resistance. Here, using the Plasmodium chabaudi mouse malaria model, we ask whether the costs and benefits of resistance are affected by the number of co‐infecting strains competing with a resistant clone. We found strong competitive suppression of resistant parasites in untreated infections and marked competitive release following treatment. The magnitude of competitive suppression depended on competitor identity. However, there was no overall effect of the diversity of susceptible parasites on the extent of competitive suppression or release. If these findings generalize, then t... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155444 Mon, 22 Aug 2011 23:00:00 +0100 5155444 http://www.medworm.com/index.php?rid=5155443&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02370.x AbstractOrganisms vary their rates of growth and development in response to environmental inputs. Such developmental plasticity may be adaptive and positively correlate with environmental heterogeneity. However, the evolution of developmental plasticity among closely related taxa is not well understood. To determine the evolutionary pattern of plasticity, we compared plasticity in time to and size at metamorphosis in response to water desiccation in tadpoles among spadefoot species that differ in breeding pond and larval period durations. Like most tadpoles, spadefoot tadpoles possess the remarkable ability to accelerate development in response to pond drying to avoid desiccation. Here, we hypothesize that desert spadefoot tadpoles have evolved reduced plasticity to avoid desiccation in ep... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155443 Mon, 22 Aug 2011 23:00:00 +0100 5155443 http://www.medworm.com/index.php?rid=5155442&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02371.x AbstractGeographical variation in behaviour within species is common. However, how behavioural plasticity varies between and within locally adapted populations is less studied. Here, we studied behavioural plasticity induced by perceived predation risk and food availability in pond (low predation – high competition) vs. coastal marine (high predation – low competition) nine‐spined sticklebacks (Pungitius pungitius) reared in a common garden experiment. Pond sticklebacks were more active feeders, more risk‐taking, aggressive and explorative than marine sticklebacks. Perceived predation risk decreased aggression and risk‐taking of all fish. Food restriction increased feeding activity and risk‐taking. Pond sticklebacks became more risk‐taking than marine sticklebacks under food ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155442 Mon, 22 Aug 2011 23:00:00 +0100 5155442 http://www.medworm.com/index.php?rid=5155441&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02372.x AbstractHabitat usage comprises interactions between ecological parameters and organismal capacities, and the selective pressures that ultimately determine the outcome of such processes in an evolutionary scale may be conflicting when the same morphological structure is recruited for different activities. Here, we investigate the roles of diet and locomotion in the evolution of cranial design in gymnophthalmid lizards and test the hypothesis that microhabitat use drives head shape evolution, particularly in head‐first burrowers. Morphological factors were analysed in relation to continuous ecological indexes (prey hardness and substrate compactness) using conventional and phylogenetic approaches. Results suggest that the evolution of head morphology in Gymnophthalmidae was shaped under t... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5155441 Mon, 22 Aug 2011 23:00:00 +0100 5155441 http://www.medworm.com/index.php?rid=5137678&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02367.x We examined changes in olfactory signals with senescence in house mice (Mus musculus domesticus), where males excrete volatile and involatile molecules in scent marks that elicit behavioural and priming responses in females. Compared to middle‐aged males, the urine of senesced males contained a lower concentration of involatile signalling proteins (major urinary proteins or MUPs), and associated volatiles that bind to these proteins. The reduced intensity of male scent will affect the longevity of scent signals deposited in the environment and, accordingly, females were less attracted to urine from senesced males deposited 12 h previously. Females also discriminated against senesced males encountered behind a mesh barrier. These results reveal that investment in olfactory signalling is... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137678 Wed, 17 Aug 2011 16:44:19 +0100 5137678 http://www.medworm.com/index.php?rid=5137684&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02361.x We examined the effect of increasing the number of sampled amplified fragment length polymorphism (AFLP) bands to reconstruct an accurate and well‐supported AFLP‐based phylogeny. In silico AFLP was performed using simulated DNA sequences evolving along balanced and unbalanced model trees with recent, uniform and ancient radiations and average branch lengths (from the most internal node to the tip) ranging from 0.02 to 0.05 substitutions per site. Trees were estimated by minimum evolution (ME) and maximum parsimony (MP) methods from both DNA sequences and virtual AFLP fingerprints. The comparison of the true tree with the estimated AFLP trees suggests that moderate numbers of AFLP bands are necessary to recover the correct topology with high bootstrap support values (i.e. >70%). Fewe... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137684 Mon, 15 Aug 2011 23:00:00 +0100 5137684 http://www.medworm.com/index.php?rid=5137683&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02362.x AbstractContemporary geographical range and patterns of genetic diversity within species reflect complex interactions between multiple factors acting across spatial and temporal scales, and it is notoriously difficult to disentangle causation. Here, we quantify patterns of genetic diversity and genetic population structure using mitochondrial DNA sequences (101 individuals, cytochrome b) and microsatellites (816 individuals, 12 loci) and use Approximate Bayesian computation methods to test competing models of the demographic history of eastern and western foxsnakes. Our analyses indicate that post‐glacial colonization and past population declines, probably caused by the infilling of deciduous forest and cooler temperatures since the mid‐Holocene, largely underpin large‐scale genetic ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137683 Mon, 15 Aug 2011 23:00:00 +0100 5137683 http://www.medworm.com/index.php?rid=5137682&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02363.x AbstractThe expression of infectious disease is increasingly recognized to be impacted by maternal effects, where the environmental conditions experienced by mothers alter resistance to infection in offspring, independent of heritability. Here, we studied how maternal effects (high or low food availability to mothers) mediated the resistance of the crustacean Daphnia magna to its bacterial parasite Pasteuria ramosa. We sought to disentangle maternal effects from the effects of host genetic background by studying how maternal effects varied across 24 host genotypes sampled from a natural population. Under low‐food conditions, females produced offspring that were relatively resistant, but this maternal effect varied strikingly between host genotypes, i.e. there were genotype by maternal en... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137682 Mon, 15 Aug 2011 23:00:00 +0100 5137682 http://www.medworm.com/index.php?rid=5137681&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02364.x AbstractCuticular hydrocarbons (CHCs) are increasingly recognized as important to insects and are used for constructing taxonomies. However, multiple parameters affect the expression of CHCs besides a genetic component. We propose that selection may act differently on the expression of CHCs, depending on the evolutionary context. To explore the influence of selection, the CHCs of two closely related ant species, Lasius niger and Lasius platythorax, were studied in a multidisciplinary approach. We characterized (i) CHCs and (ii) niches (through baiting, activity observations and foraging analysis). The species were distinct in both measures, although to a varying degree. Although they showed moderate niche partitioning along diet and environmental preferences, chemical differences were unex... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137681 Mon, 15 Aug 2011 23:00:00 +0100 5137681 http://www.medworm.com/index.php?rid=5137680&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02365.x AbstractTheory suggests that sexual traits evolve faster than ecological characters. However, characteristics of a species niche may also influence evolution of sexual traits. Hence, a pending question is whether ecological characters and sexual traits present similar tempo and mode of evolution during periods of rapid ecological divergence, such as adaptive radiation. Here, we use recently developed phylogenetic comparative methods to analyse the temporal dynamics of evolution for ecological and sexual traits in Tanganyikan cichlids. Our results indicate that whereas disparity in ecological characters was concentrated early in the radiation, disparity in sexual traits remained high throughout the radiation. Thus, closely related Tanganyikan cichlids presented higher disparity in sexual tr... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137680 Mon, 15 Aug 2011 23:00:00 +0100 5137680 http://www.medworm.com/index.php?rid=5137679&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02366.x AbstractTheory proposes that sexually dimorphic, polygynous species are at particularly high risk of sex‐biased predation, because conspicuous males are more often preyed upon compared to females. We tested the effects of predation on population sex ratio in a highly sexually dimorphic insect genus (Hemideina). In addition, introduction of a suite of novel mammalian predators to New Zealand during the last 800 years is likely to have modified selection pressures on native tree weta. We predicted that the balance between natural and sexual selection would be disrupted by the new predator species. We expected to see a sex ratio skew resulting from higher mortality in males with expensive secondary sexual weaponry; combat occurs outside refuge cavities between male tree weta. We took a me... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5137679 Mon, 15 Aug 2011 23:00:00 +0100 5137679 http://www.medworm.com/index.php?rid=5124358&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02354.x (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5124358 Sat, 13 Aug 2011 07:09:29 +0100 5124358 http://www.medworm.com/index.php?rid=5094108&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02359.x AbstractA comprehensive knowledge on the genetic basis of coloration is crucial to understand how new colour phenotypes arise and how they contribute to the emergence of new species. Variation in melanocortin‐1 receptor (Mc1r), a gene that has been reported as a target for repeated evolution in a wide range of vertebrate taxa, was assessed in European ocellated lizards (Lacerta lepida) to search for associations with melanin‐based colour phenotypes. Lacerta lepida subspecies’ distribution is associated with the three major bio‐climatic regions in the Iberian Peninsula. A nonconserved and derived substitution (T162I) was associated with the L. l. nevadensis phenotype (prevalence of brown scales). Another substitution (S172C) was associated with the presence of black scales in both ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5094108 Wed, 03 Aug 2011 23:00:00 +0100 5094108 http://www.medworm.com/index.php?rid=5116944&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02358.x AbstractIn quantitative genetics, the degree of resemblance between parents and offspring is described in terms of the additive variance (VA) relative to genetic (VG) and phenotypic (VP) variance. For populations with extreme allele frequencies, high VA/VG can be explained without considering properties of the genotype–phenotype (GP) map. We show that randomly generated GP maps in populations with intermediate allele frequencies generate far lower VA/VG values than empirically observed. The main reason is that order‐breaking behaviour is ubiquitous in random GP maps. Rearrangement of genotypic values to introduce order‐preservation for one or more loci causes a dramatic increase in VA/VG. This suggests the existence of order‐preserving design principles in the regulatory machinery ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5116944 Sun, 31 Jul 2011 23:00:00 +0100 5116944 http://www.medworm.com/index.php?rid=5094107&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02360.x AbstractPhenotypic plasticity is an important strategy for coping with changing environments. However, environmental change usually results in strong directional selection, and little is known empirically about how this affects plasticity. If genes affecting a trait value also affect its plasticity, selection on the trait should influence plasticity. Synthetic outbred populations of Arabidopsis thaliana were selected for earlier flowering under simulated spring‐ and winter‐annual conditions to investigate the correlated response of flowering time plasticity and its effect on family‐by‐environment variance (Vg×e) within each selected line. We found that selection affected plasticity in an environmentally dependent manner: under simulated spring‐annual conditions, selection increa... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5094107 Sun, 31 Jul 2011 23:00:00 +0100 5094107 http://www.medworm.com/index.php?rid=5048154&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02356.x AbstractWe examine the maintenance of a plumage polymorphism, variation in plumages among the same age and sex class within a population, in a population of Swainson’s Hawks. We take advantage of 32 years of data to examine two prevalent hypotheses used to explain the persistence of morphs: apostatic selection and heterozygous advantage. We investigate differences in fitness among three morph classes of a melanistic trait in Swainson’s Hawks: light (7% of the local breeding population), intermediate (57%) and dark (36%). Specifically, we examined morph differences in adult apparent survival, breeding success, annual number of fledglings produced, probability of offspring recruitment into the breeding population and lifetime reproductive success (LRS). If apostatic selection were a fa... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5048154 Thu, 21 Jul 2011 23:26:51 +0100 5048154 http://www.medworm.com/index.php?rid=5048155&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02355.x AbstractSmall population size is expected to induce heterosis, due to the random fixation and accumulation of mildly deleterious mutations, whereas within‐population inbreeding depression should decrease due to increased homozygosity. Population bottlenecks, although less effective, may have similar consequences. We tested this hypothesis in the self‐fertile freshwater snail Lymnaea stagnalis, by subjecting experimental populations to a single bottleneck of varied magnitude. Although patterns were not strong, heterosis was significant in the most severely bottlenecked populations, under stressful conditions. This was mainly due to hatching rate, suggesting that early acting and highly deleterious alleles were involved. Although L. stagnalis is a preferential outcrosser, inbreeding dep... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5048155 Sun, 17 Jul 2011 23:00:00 +0100 5048155 http://www.medworm.com/index.php?rid=5017704&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02346.x This study supports the hypothesis that fitness compensation via resource reallocation can explain male‐killing bacteria persistence. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5017704 Sun, 10 Jul 2011 23:00:00 +0100 5017704 http://www.medworm.com/index.php?rid=5017703&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02351.x AbstractLife‐history theory predicts that older females will increase reproductive effort through increased fecundity. Unless offspring survival is density dependent or female size constrains offspring size, theory does not predict variation in offspring size. However, empirical data suggest that females of differing age or condition produce offspring of different sizes. We used a dynamic state‐variable model to determine when variable offspring sizes can be explained by an interaction between female age, female state and survival costs of reproduction. We found that when costs depend on fecundity, young females with surplus state increase offspring size and reduce number to minimize fitness penalties. When costs depend on total reproductive effort, only older females increase offsprin... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5017703 Sun, 10 Jul 2011 23:00:00 +0100 5017703 http://www.medworm.com/index.php?rid=5017702&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02352.x AbstractExperimental work on Polygonia c‐album, a temperate polyphagous butterfly species, has shown that Swedish, Belgian, Norwegian and Estonian females are generalists with respect to host‐plant preference, whereas females from UK and Spain are specialized on Urticaceae. Female preference is known to have a strong genetic component. We test whether the specialist and generalist populations form respective genetic clusters using data from mitochondrial sequences and 10 microsatellite loci. Results do not support this hypothesis, suggesting that the specialist and generalist traits have evolved more than once independently. Mitochondrial DNA variation suggests a rapid expansion scenario, with a single widespread haplotype occurring in high frequency, whereas microsatellite data indica... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5017702 Sun, 10 Jul 2011 23:00:00 +0100 5017702 http://www.medworm.com/index.php?rid=4997109&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02349.x AbstractCreationist literature claims that sufficient gaps in morphological continuity exist to classify dinosaurs into several distinct baramins (‘created kinds’). Here, I apply the baraminological method called taxon correlation to test for morphological continuity within and between dinosaurian taxa. The results show enough morphological continuity within Dinosauria to consider most dinosaurs genetically related, even by this creationist standard. A continuous morphological spectrum unites the basal members of Saurischia, Theropoda, Sauropodomorpha, Ornithischia, Thyreophora, Marginocephalia, and Ornithopoda with Nodosauridae and Pachycephalosauria and with the basal ornithodirans Silesaurus and Marasuchus. Morphological gaps in the known fossil record separate only seven groups fro... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4997109 Sun, 03 Jul 2011 23:00:00 +0100 4997109 http://www.medworm.com/index.php?rid=4997108&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02339.x AbstractAlthough avian malarial parasites are globally distributed, the factors that affect the geographical distribution and local prevalence of different parasite lineages across host populations or species are still poorly understood. Based on the intense screening of avian malarial parasites in nine European blue tit populations, we studied whether distribution ranges as well as local adaptation, host specialization and phylogenetic relationships can determine the observed prevalences within populations. We found that prevalence differed consistently between parasite lineages and host populations, indicating that the transmission success of parasites is lineage specific but is partly shaped by locality‐specific effects. We also found that the lineage‐specific estimate of prevalence... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4997108 Sun, 03 Jul 2011 23:00:00 +0100 4997108 http://www.medworm.com/index.php?rid=4997107&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02347.x AbstractIt is well known that standard population genetic theory predicts decreased additive genetic variance (Va) following a population bottleneck and that theoretical models including interallelic and intergenic interactions indicate such loss may be avoided. However, few empirical data from multicellular model systems are available, especially regarding variance/covariance (V/CV) relationships. Here, we compare the V/CV structure of seventeen traits related to body size and composition between control (60 mating pairs/generation) and bottlenecked (2 mating pairs/generation; average F = 0.39) strains of mice. Although results for individual traits vary considerably, multivariate analysis indicates that Va in the bottlenecked populations is greater than expected. Traits with patterns... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4997107 Sun, 03 Jul 2011 23:00:00 +0100 4997107 http://www.medworm.com/index.php?rid=5017701&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02353.x AbstractThe control mechanisms and information content of melanin‐based colourations are still debated among evolutionary biologists. Recent hypotheses contend that molecules involved in melanogenesis alter other physiological processes, thereby generating covariation between melanin‐based colouration and other phenotypic attributes. Interestingly, several molecules such as agouti and glutathione that trigger the production of reddish‐brown pheomelanin have an inhibitory effect on the production of black/grey eumelanin, whereas other hormones, such as melanocortins, have the opposite effect. We therefore propose the hypothesis that phenotypic traits positively correlated with the degree of eumelanin‐based colouration may be negatively correlated with the degree of pheomelanin‐bas... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=5017701 Thu, 30 Jun 2011 23:00:00 +0100 5017701 http://www.medworm.com/index.php?rid=4997106&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02350.x This study examines multiple postmating barriers between host forms of Neochlamisus bebbianae leaf beetles that specialize on Acer and Salix trees. We demonstrate cryptic isolation and reduced hybrid fitness via controlled matings of these host forms. These findings reveal host‐associated postmating isolation, although a nonecological, ‘intrinsic’ basis for these patterns cannot be ruled out. Host preference and performance results among cross types further suggest sex‐linked maternal effects on these traits, whereas family effects indicate their genetic basis and associated variation. Genes of major effect appear to influence these traits. Together with previous findings of premating isolation and adaptive differentiation in sympatry, our results meet many assumptions of ‘specia... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4997106 Thu, 30 Jun 2011 23:00:00 +0100 4997106 http://www.medworm.com/index.php?rid=4974545&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02345.x AbstractThe evolution of sexually monomorphic (i.e. mutual) ornamentation has attracted growing attention as a ‘blind‐spot’ in evolutionary biology. The popular consensus is that female ornaments are subject to the same modes of sexual selection as males: intrasexual competition and mate choice. However, it remains unclear how these forces interact within and between sexes, or whether they fully capture selection on female traits. One possibility is that the ‘armament–ornament’ model – which proposes that traits used primarily in male‐male contests are also co‐opted by females as indicators of male quality – can be extended to explain signal evolution in both sexes. We examine this idea by testing the function of acoustic signals in two species of duetting antbirds. Beh... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974545 Tue, 28 Jun 2011 17:51:23 +0100 4974545 http://www.medworm.com/index.php?rid=4974550&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02354.x (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974550 Sun, 26 Jun 2011 23:00:00 +0100 4974550 http://www.medworm.com/index.php?rid=4974549&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02348.x AbstractMany factors could influence progress towards sympatric speciation. Some of the potentially important ones include competition, mate choice and the degree to which alternative sympatric environments (resources) are discrete. What is not well understood is the relative importance of these different factors, as well as interactions among them. We use an individual‐based numerical model to investigate the possibilities. Mate choice was modelled as the degree to which male foraging traits influence female mate choice. Competition was modelled as the degree to which individuals with different phenotypes compete for portions of the resource distribution. Discreteness of the environment was modelled as the degree of bimodality of the underlying resource distribution. We find that strong... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974549 Sun, 26 Jun 2011 23:00:00 +0100 4974549 http://www.medworm.com/index.php?rid=4974548&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02337.x AbstractEcologists have had limited success in understanding which introduced species may become invasive. An evolutionary model is used to investigate which traits are associated with invasiveness. Translocation experiments were simulated in which species were moved into similar but evolutionarily younger communities. The main findings were that species that had previously been the most abundant in their original communities have significantly higher rates of establishment than did species that had previously occurred at low abundance in their original community. However, if establishment did occur, previously abundant and previously low‐abundant species were equally likely to become dominant and were equally likely to exclude other species from their new community. There was a suggesti... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974548 Sun, 26 Jun 2011 23:00:00 +0100 4974548 http://www.medworm.com/index.php?rid=4974547&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02340.x AbstractThe dorsal crest of newts (Salamandridae) is a novel, phenotypically plastic, sexually selected trait that may evolve in association with complex courtship behaviours. We estimated a near‐comprehensive, time‐calibrated phylogeny for salamandrids and analysed the evolution of their crests and display behaviour. Different models give conflicting reconstructions for crest evolution, showing that likelihood can estimate incorrect ancestral states with strong statistical support. The best‐fitting model suggests that crests evolved once and were lost repeatedly, supporting the hypothesis that sexually selected traits may be frequently lost. We demonstrate the correlated evolution of crests and courtship behaviour and show that species with larger numbers of crest‐related traits h... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974547 Sun, 26 Jun 2011 23:00:00 +0100 4974547 http://www.medworm.com/index.php?rid=4974546&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02342.x AbstractMigration is a complex trait although little is known about genetic correlations between traits involved in such migration syndromes. To assess the migratory responses to climate change, we need information on genetic constraints on evolutionary potential of arrival dates in migratory birds. Using two long‐term data sets on barn swallows Hirundo rustica (from Spain and Denmark), we show for the first time in wild populations that spring arrival dates are phenotypically and genetically correlated with morphological and life history traits. In the Danish population, length of outermost tail feathers and wing length were negatively genetically correlated with arrival date. In the Spanish population, we found a negative genetic correlation between arrival date and time elapsed betwee... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4974546 Sun, 26 Jun 2011 23:00:00 +0100 4974546 http://www.medworm.com/index.php?rid=4967487&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02338.x AbstractTemnospondyls were a successful group of early tetrapods that lived during the Palaeozoic and Mesozoic periods. Different ecomorphotypes were present (terrestrial, amphibious and fully aquatic) with a wide range of lifestyles. Herein, we analysed several clades of temnospondyls using geometric morphometrics, Finite Element Analysis, and comparative phylogenetic analysis. Some temnospondyli clades were ‘crocodilomorph’ feeding analogues. The skull analysis reveals a concordance between form and feeding function, in amphibious and fully aquatic feeders. The form of terrestrial feeders could be consequences of adaptative or phylogenetical constraints. Basal temnospondyls, as edopoids, were able to leave the water and feed on land. Eryopids continued as terrestrial feeders, althoug... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967487 Sun, 26 Jun 2011 16:48:53 +0100 4967487 http://www.medworm.com/index.php?rid=4967492&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02331.x AbstractSocial evolution in honey bees has produced strong queen–worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental programme includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body size and ovary size for two pairs of honey bee lineages that show similar differences in worker body–ovary size allometry but have diverged over different evolutionary timescales. Our results indicate that the lineages have diverged for both nurse and larval developmental components, that rapid changes in worker body–ovary size allometry may disrupt queen development and that queen–work... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967492 Wed, 22 Jun 2011 23:00:00 +0100 4967492 http://www.medworm.com/index.php?rid=4967491&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02336.x Abstract Colour polymorphism in vertebrates is usually under genetic control and may be associated with variation in physiological traits. The melanocortin 1 receptor (Mc1r) has been involved repeatedly in melanin‐based pigmentation but it was thought to have few other physiological effects. However, recent pharmacological studies suggest that MC1R could regulate the aspects of immunity. We investigated whether variation at Mc1r underpins plumage colouration in the Eleonora’s falcon. We also examined whether nestlings of the different morphs differed in their inflammatory response induced by phytohemagglutinin (PHA). Variation in colouration was due to a deletion of four amino acids at the Mc1r gene. Cellular immune response was morph specific. In males, but not in females, dark nestli... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967491 Wed, 22 Jun 2011 23:00:00 +0100 4967491 http://www.medworm.com/index.php?rid=4967490&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02341.x In conclusion, our findings do not support divergence of D. simulans populations across Lower Nahal Oren. (Source: Journal of Evolutionary Biology) Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967490 Wed, 22 Jun 2011 23:00:00 +0100 4967490 http://www.medworm.com/index.php?rid=4967489&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02343.x AbstractMating systems are shaped by a species’ ecology, which sets the stage for sexual selection. Males of the gregarious parasitoid wasp Nasonia vitripennis compete to mate virgin females at the natal site, before females disperse. Males could increase their fitness by being larger and monopolizing female emergence sites or by emerging earlier pre‐empting access to females. We consider sexual selection on male body size and development time in Nasonia, and a potential trade‐off between the two traits. We explored sex‐specific patterns of larval and pupal development, finding that smaller wasps developed slower than their host‐mates. Using competition experiments between brothers, we found that earlier eclosing males mated more females independently of absolute and relative bod... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967489 Wed, 22 Jun 2011 23:00:00 +0100 4967489 http://www.medworm.com/index.php?rid=4967488&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02344.x AbstractAccording to the ‘pace‐of‐life’ syndrome hypothesis, differences in resting metabolic rate (RMR) should be genetically associated with exploratory behaviour. A large number of studies reported significant heritability for both RMR and exploratory behaviour, but the genetic correlation between the two has yet to be documented. We used a quantitative genetic approach to decompose the phenotypic (co)variance of several metabolic and behavioural measures into components of additive genetic, common environment and permanent environment variance in captive deer mice. We found significant additive genetic variance for two mass‐independent metabolic measures (RMR and the average metabolic rate throughout the respirometry run) and two behavioural measures (time spent in centre and... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4967488 Wed, 22 Jun 2011 23:00:00 +0100 4967488 http://www.medworm.com/index.php?rid=4944116&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02335.x AbstractComplex phenotypes are often controlled by many interacting genes. One question emerging from such organization is how selection, acting at the phenotypic level, shapes the evolution of genes involved in regulatory networks controlling the phenotypes. We studied this issue through a matrix model of such networks. In a population submitted to selection, we simulated the evolution of a quantitative trait controlled by a set of loci that regulate each other through positive or negative interactions. Investigating several levels of selection intensity on the trait, we studied the evolution of regulation intensity between the genes and the evolution of the genetic diversity of those genes as an indirect measure of the strength of selection acting on them. We show that an increasing inte... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4944116 Sun, 19 Jun 2011 07:13:21 +0100 4944116 http://www.medworm.com/index.php?rid=4944118&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02327.x AbstractThe mechanisms by which phenotypic and genetic divergence may occur among sympatric, conspecific populations have been widely discussed but are still not well understood. Possible mechanisms include assortative mating based on morphology or variation in the reproductive behaviour of phenotypes, and both have been suggested to be relevant to the differentiation of salmonid populations in post‐glacial lakes. Here, we studied Arctic charr (Salvelinus alpinus) in Windermere, where putative populations are defined by spatial and temporal variation in spawning. Genetic differentiation was assessed based on nine microsatellite loci, and phenotypic variation was assessed from morphometric characters. We test hypotheses about the relative role of morphology, spawning season and spawning h... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4944118 Thu, 16 Jun 2011 23:00:00 +0100 4944118 http://www.medworm.com/index.php?rid=4944117&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02334.x AbstractThe life history schedules of wild organisms have long attracted scientific interest, and, in light of ongoing climate change, an understanding of their genetic and environmental underpinnings is increasingly becoming of applied concern. We used a multi‐generation pedigree and detailed phenotypic records, spanning 18 years, to estimate the quantitative genetic influences on the timing of hibernation emergence in a wild population of Columbian ground squirrels (Urocitellus columbianus). Emergence date was significantly heritable [h2 = 0.22 ± 0.05 (in females) and 0.34 ± 0.14 (in males)], and there was a positive genetic correlation (rG = 0.76 ± 0.22) between male and female emergence dates. In adult females, the heritabilities of body mass at emergence and... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4944117 Thu, 16 Jun 2011 23:00:00 +0100 4944117 http://www.medworm.com/index.php?rid=4919930&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02325.x We examined the relationship between copulation duration (prior to spermatophore transfer), the complexity of titillators (sclerotized male genital contact structures), spermatophore mass and male body mass across 54 species of bushcricket. Using phylogenetic comparative analyses, we found that copulation duration was much longer in species with titillators than those without, but it was not longer in species with complex compared with simple titillators. A positive relationship was found between spermatophore size and copulation duration prior to ejaculate transfer, which supports the hypothesis that this represents a period of mate assessment. The slope of this relationship was steeper in species with simple rather than complex titillators. Although the data suggest that the presence of ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4919930 Thu, 09 Jun 2011 23:00:00 +0100 4919930 http://www.medworm.com/index.php?rid=4919929&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02300.x AbstractParasites detrimentally affect host fitness, leading to expectations of positive selection on host parasite resistance. However, as immunity is costly, host fitness may be maximized at low, but nonzero, parasite infection intensities. These hypotheses are rarely tested on natural variation in free‐living populations. We investigated selection on a measure of host parasite resistance in a naturally regulated Soay sheep population using a longitudinal data set and found negative correlations between parasite infection intensity and annual fitness in lambs, male yearlings and adult females. However, having accounted for confounding effects of body weight, the effect was only significant in lambs. Associations between fitness and parasite resistance were environment‐dependent, bein... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4919929 Thu, 09 Jun 2011 23:00:00 +0100 4919929 http://www.medworm.com/index.php?rid=4919928&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02322.x AbstractColonization of new habitats can relax selection pressures, and traits or trait combinations no longer selected for might become reduced or lost. We investigated behavioural differentiation and behavioural trait integration in the freshwater isopod Asellus aquaticus. This isopod has recently colonized a novel habitat and diverged into two ecotypes which encounter different predator faunas. We investigated sex‐specific behavioural differences and phenotypic integration in three behavioural assays: (i) time to emerge (TE) from a shelter, (ii) activity and (iii) escape behaviour. General activity and escape behaviour differed between ecotypes. Furthermore, general activity and TE differed between sexes. Behavioural traits were more frequently correlated in the ancestral habitat, and... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4919928 Thu, 09 Jun 2011 23:00:00 +0100 4919928 http://www.medworm.com/index.php?rid=4919927&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02323.x AbstractTheory predicts that if most mutations are deleterious to both overall fitness and condition‐dependent traits affecting mating success, sexual selection will purge mutation load and increase nonsexual fitness. We explored this possibility with populations of mutagenized Drosophila melanogaster exhibiting elevated levels of deleterious variation and evolving in the presence or absence of male–male competition and female choice. After 60 generations of experimental evolution, monogamous populations exhibited higher total reproductive output than polygamous populations. Parental environment also affected fitness measures – flies that evolved in the presence of sexual conflict showed reduced nonsexual fitness when their parents experienced a polygamous environment, indicating tra... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4919927 Thu, 09 Jun 2011 23:00:00 +0100 4919927 http://www.medworm.com/index.php?rid=4910250&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02319.x AbstractAnimals should decipher information about the genetic make‐up of conspecifics in order to enhance the fitness benefits associated with mate choice. Although there is increasing evidence to suggest that animals make genetically informed decisions about their mating partners, we understand relatively little about the sensory mechanisms informing these decisions. Here, we investigate whether cuticular hydrocarbons, chemical compounds found on the cuticle of most terrestrial arthropods, provide a means of discerning genetic similarity during mate choice in the cricket, Teleogryllus oceanicus. We found that individuals preferentially mated with partners who share more dissimilar cuticular hydrocarbon profiles and that similarity in cuticular hydrocarbon profiles between mating pairs c... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4910250 Tue, 07 Jun 2011 23:00:00 +0100 4910250 http://www.medworm.com/index.php?rid=4910249&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02330.x AbstractEcological selection against hybrids between populations occupying different habitats might be an important component of reproductive isolation during the initial stages of speciation. The strength and directionality of this barrier to gene flow depends on the genetic architecture underlying divergence in ecologically relevant phenotypes. We here present line cross analyses of inheritance for two key foraging‐related morphological traits involved in adaptive divergence between stickleback ecotypes residing parapatrically in lake and stream habitats within the Misty Lake watershed (Vancouver Island, Canada). One main finding is the striking genetic dominance of the lake phenotype for body depth. Selection associated with this phenotype against first‐ and later‐generation hybri... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4910249 Tue, 07 Jun 2011 23:00:00 +0100 4910249 http://www.medworm.com/index.php?rid=4910248&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02332.x AbstractThe mechanism that facilitates the evolution of maternal care is ambiguous in egg‐laying terrestrial vertebrates: does the ability of mothers to recognize their own eggs lead them under some circumstances to begin providing care or can maternal care evolve from simply being in close proximity to the eggs (e.g. through territorial behaviour)? This question is difficult to answer because in most species, parental care is either absent altogether or present; in only a few species we have the opportunity to observe intraspecific variation in the expression of parental care. We studied a population of long‐tailed skinks (Eutropis longicaudata) in which females have recently evolved maternal care from a noncaring state. Females on Orchid Island, Taiwan, remain with their eggs during ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4910248 Tue, 07 Jun 2011 23:00:00 +0100 4910248 http://www.medworm.com/index.php?rid=4901122&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02316.x AbstractThe evolution of animal genitalia has gained renewed interest because of their potential roles during sexual selection and early stages of species formation. Although central to understanding the evolutionary process, knowledge of the genetic basis of natural variation in genital morphology is limited to a very few species. Using an outbred cross between phylogenetically distinct lines of Drosophila montana, we characterized quantitative trait loci (QTLs) affecting the size and shape of the distiphallus, a prominent part of the male intromittent organ. Our microsatellite‐based linkage analysis shows that intra‐specific variation in the distiphallus involves several QTLs of largely additive effect and that a highly significant QTL co‐localizes with the same inversion where we ... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4901122 Thu, 02 Jun 2011 23:00:00 +0100 4901122 http://www.medworm.com/index.php?rid=4901121&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02320.x AbstractMutation rate may be condition dependent, whereby individuals in poor condition, perhaps from high mutation load, have higher mutation rates than individuals in good condition. Agrawal (J. Evol. Biol.15, 2002, 1004) explored the basic properties of fitness‐dependent mutation rate (FDMR) in infinite populations and reported some heuristic results for finite populations. The key parameter governing how infinite populations evolve under FDMR is the curvature (k) of the relationship between fitness and mutation rate. We extend Agrawal's analysis to finite populations and consider dominance and epistasis. In finite populations, the probability of long‐term existence depends on k. In sexual populations, positive curvature leads to low equilibrium mutation rate, whereas negative curva... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4901121 Thu, 02 Jun 2011 23:00:00 +0100 4901121 http://www.medworm.com/index.php?rid=4891449&cid=s_32057_62_f&fid=32057&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1420-9101.2011.02295.x AbstractThe extent to which heterozygosity‐fitness correlations (HFCs) are expected in wild populations is an important and unresolved question in evolutionary biology, because it relates to our understanding of the genetic architecture of fitness. Here, we report a study of HFCs in a wild, noninbred population of great tits (Parus major), based on a sample comprising 281 individuals typed at 26 markers, resulting in a data set comprising over 5600 genotypes. We regressed pedigree‐derived f‐score and multilocus genetic diversity against eight life‐history traits known to be associated with fitness in this population, including lifetime reproductive success (LRS), as well as several morphological traits under weak selection. We found no evidence for either multilocus or single‐loc... Journal of Evolutionary Biology journals http://www.medworm.com/rss/comments.php?id=4891449 Thu, 02 Jun 2011 23:00:00 +0100 4891449