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 'Biological Reviews' source. Mon, 06 Feb 2012 14:25:58 +0100 http://www.medworm.com/index.php?rid=5656305&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2012.00218.x A healthy human body contains at least tenfold more bacterial cells than human cells and the most abundant and diverse microbial community resides in the intestinal tract. Intestinal health is not only maintained by the human intestine itself and by dietary factors, but is also largely supported by this resident microbial community. Conversely, however, a large body of evidence supports a relationship between bacteria, bacterial activities and human colorectal cancer. Symbiosis in this multifaceted organ is thus crucial to maintain a healthy balance within the host‐diet‐microbiota triangle and accordingly, changes in any of these three factors may drive a healthy situation into a state of disease. In this review, the factors that sustain health or drive this complex intestinal system i... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5656305 Wed, 01 Feb 2012 05:00:00 +0100 5656305 http://www.medworm.com/index.php?rid=5624611&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00216.x Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human‐modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: ‘landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis—the size of the landscape‐wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5624611 Tue, 24 Jan 2012 19:48:08 +0100 5624611 http://www.medworm.com/index.php?rid=5568676&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00215.x Fish aquaculture for commodity production, fisheries enhancement and conservation is expanding rapidly, with many cultured species undergoing inadvertent or controlled domestication. Cultured fish are frequently released, accidentally and deliberately, into natural environments where they may survive well and impact on wild fish populations through ecological, genetic, and technical interactions. Impacts of fish released accidentally or for fisheries enhancement tend to be negative for the wild populations involved, particularly where wild populations are small, and/or highly adapted to local conditions, and/or declining. Captive breeding and supplementation can play a positive role in restoring threatened populations, but the biology of threatened populations and the potential of culture ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5568676 Sat, 07 Jan 2012 01:39:58 +0100 5568676 http://www.medworm.com/index.php?rid=5533160&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00213.x Most carnivorous plants utilize insects in two ways: the flowers attract insects as pollen vectors for sexual reproduction, and the leaves trap insects for nutrients. Feeding on insects has been explained as an adaptation to nutrient‐poor soil, and carnivorous plants have been shown to benefit from insect capture through increased growth, earlier flowering and increased seed production. Most carnivorous plant species seem to benefit from insect pollination, although many species autonomously self‐pollinate and some propagate vegetatively. However, assuming that outcross pollen is advantageous and is a more important determinant of reproductive success than the nutrients gained from prey, there should be a selective pressure on carnivorous plants not to feed on their potential pollen ve... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5533160 Wed, 21 Dec 2011 05:00:00 +0100 5533160 http://www.medworm.com/index.php?rid=5417393&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00205.x Animal‐mediated pollination is essential for both ecosystem services and conservation of global biodiversity, but a growing body of work reveals that it is negatively affected by anthropogenic disturbance. Landscape‐scale disturbance results in two often inter‐related processes: (1) habitat loss, (2) disruptions of habitat configuration (i.e. fragmentation). Understanding the relative effects of such processes is critical in designing effective management strategies to limit pollination and pollinator decline. We reviewed existing published work from 1989 to 2009 and found that only six of 303 studies considering the influence of landscape context on pollination separated the effects of habitat loss from fragmentation. We provide a synthesis of the current landscape, behavioural, and... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5417393 Thu, 17 Nov 2011 05:00:00 +0100 5417393 http://www.medworm.com/index.php?rid=5375011&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00208.x Stable isotope analysis has emerged as one of the primary means for examining the structure and dynamics of food webs, and numerous analytical approaches are now commonly used in the field. Techniques range from simple, qualitative inferences based on the isotopic niche, to Bayesian mixing models that can be used to characterize food‐web structure at multiple hierarchical levels. We provide a comprehensive review of these techniques, and thus a single reference source to help identify the most useful approaches to apply to a given data set. We structure the review around four general questions: (1) what is the trophic position of an organism in a food web?; (2) which resource pools support consumers?; (3) what additional information does relative position of consumers in isotopic space r... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5375011 Wed, 02 Nov 2011 04:00:00 +0100 5375011 http://www.medworm.com/index.php?rid=5533159&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00214.x Females in many taxa experience postmating activation of their immune system, independently of any genital trauma or pathogenic attack arising from male‐female genital contact. This response has always been interpreted as a product of natural selection as it either prepares the female immune system for antigens arising from an implanted embryo (in the case of placental mammals), or is a “pre‐emptive strike” against infection or injury acquired during mating. While the first hypothesis has empirical support, the second is not entirely satisfactory. Recently, studies that have experimentally dissected the postmating responses of Drosophila melanogaster females point to a different explanation: male reproductive peptides/proteins that have evolved in response to postmating male‐male... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5533159 Tue, 01 Nov 2011 04:00:00 +0100 5533159 http://www.medworm.com/index.php?rid=5512267&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00212.x There has been recent discussion about the evolutionary pressures underlying the long necks of extant giraffes and extinct sauropod dinosaurs. Here we summarise these debates and place them in a wider taxonomic context. We consider the evolution of long necks across a wide range of (both living and extinct) taxa and ask whether there has been a common selective factor or whether each case has a separate explanation. We conclude that in most cases long necks can be explained in terms of foraging requirements, and that alternative explanations in terms of sexual selection, thermoregulation and predation pressure are not as well supported. Specifically, in giraffe, tortoises, and perhaps sauropods there is likely to have been selection for high browsing. It the last case there may also have b... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5512267 Tue, 01 Nov 2011 04:00:00 +0100 5512267 http://www.medworm.com/index.php?rid=5500992&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00211.x The giant salamanders are aquatic and paedomorphic urodeles including the genera Andrias and Cryptobranchus (Cryptobranchidae), Amphiuma (Amphiumidae), Siren (Sirenidae), and Necturus (Proteidae, of which only N. maculosus is considered ‘a giant'). Species in the genera Cryptobranchus and Necturus are considered aquatic salamanders well adapted for breathing water, poorly adapted for breathing air, and with limited abilities to compensate acid‐base disturbances. As such, they are water‐breathing animals with a somewhat fish‐like respiratory and acid‐base physiology, whose habitat selection is limited to waters that do not typically become hypoxic or hypercarbic (although this assertion has been questioned for N. maculosus). Siren and Amphiuma species, by contrast, are dependent u... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5500992 Tue, 01 Nov 2011 04:00:00 +0100 5500992 http://www.medworm.com/index.php?rid=5465085&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00210.x Here we review how adaptive traits contribute to the emergence and maintenance of species richness gradients through their influence on demographic and diversification processes. We start by reviewing how demographic dynamics change along species richness gradients. Empirical studies show that geographical clines in population parameters and measures of demographic variability are frequent along latitudinal and altitudinal gradients. Demographic variability often increases at the extremes of regional species richness gradients and contributes to shape these gradients. Available studies suggest that adaptive traits significantly influence demographic dynamics, and set the limits of species distributions. Traits related to thermal tolerance, resource use, phenology and dispersal seem to play... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5465085 Tue, 01 Nov 2011 04:00:00 +0100 5465085 http://www.medworm.com/index.php?rid=5417392&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00209.x Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one‐third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understan... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5417392 Tue, 01 Nov 2011 04:00:00 +0100 5417392 http://www.medworm.com/index.php?rid=5375010&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00203.x Top‐order predators often have positive effects on biological diversity owing to their key functional roles in regulating trophic cascades and other ecological processes. Their loss has been identified as a major factor contributing to the decline of biodiversity in both aquatic and terrestrial systems. Consequently, restoring and maintaining the ecological function of top predators is a critical global imperative. Here we review studies of the ecological effects of the dingo Canis lupus dingo, Australia's largest land predator, using this as a case study to explore the influence of a top predator on biodiversity at a continental scale. The dingo was introduced to Australia by people at least 3500 years ago and has an ambiguous status owing to its brief history on the continent, its adve... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5375010 Tue, 01 Nov 2011 04:00:00 +0100 5375010 http://www.medworm.com/index.php?rid=5355236&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00206.x Fossils of chironomid larvae (non‐biting midges) preserved in lake sediments are well‐established palaeotemperature indicators which, with the aid of numerical chironomid‐based inference models (transfer functions), can provide quantitative estimates of past temperature change. This approach to temperature reconstruction relies on the strong relationship between air and lake surface water temperature and the distribution of individual chironomid taxa (species, species groups, genera) that has been observed in different climate regions (arctic, subarctic, temperate and tropical) in both the Northern and Southern hemisphere. A major complicating factor for the use of chironomids for palaeoclimate reconstruction which increases the uncertainty associated with chironomid‐based temperat... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5355236 Fri, 28 Oct 2011 00:26:58 +0100 5355236 http://www.medworm.com/index.php?rid=5355237&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00207.x It has been argued by some neozoologists (those who study living animals) that the palaeozoological record is biased and incomplete (relative to an existing biological community) and therefore should not be consulted for purposes of conservation biology. An article published in a biology journal in 2011 lists numerous reasons why natural history collections (NHCs) of skins and skulls of animals collected over the past century or two are exceptionally valuable to conservation biologists because those collections provide significant time depth to numerous variables that document global biological change. Many of those same variables can be, and have been, identified in the palaeozoological record. Those variables are of major value to conservation biology, whether their values are taken from... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5355237 Thu, 27 Oct 2011 04:00:00 +0100 5355237 http://www.medworm.com/index.php?rid=5310620&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00197.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5310620 Thu, 13 Oct 2011 09:16:48 +0100 5310620 http://www.medworm.com/index.php?rid=5233279&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00199.x We present a new synthesis for how these fundamental traits may affect the molecular mechanisms of regeneration at the tissue, cellular, and genomic levels of biological organization. Future studies that explore regeneration in organisms across a broad phylogenetic scale, and within an ontogenetic framework, will help elucidate the proximate mechanisms that modulate regeneration and may reveal new biomedical applications for use in regenerative medicine. (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5233279 Mon, 19 Sep 2011 04:00:00 +0100 5233279 http://www.medworm.com/index.php?rid=5233278&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00198.x Intertidal wetlands such as saltmarshes and mangroves provide numerous important ecological functions, though they are in rapid and global decline. To better conserve and restore these wetland ecosystems, we need an understanding of the fundamental natural bottlenecks and thresholds to their establishment and long‐term ecological maintenance. Despite inhabiting similar intertidal positions, the biological traits of these systems differ markedly in structure, phenology, life history, phylogeny and dispersal, suggesting large differences in biophysical interactions. By providing the first systematic comparison between saltmarshes and mangroves, we unravel how the interplay between species‐specific life‐history traits, biophysical interactions and biogeomorphological feedback processes ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5233278 Mon, 19 Sep 2011 04:00:00 +0100 5233278 http://www.medworm.com/index.php?rid=5233277&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00201.x Dispersal costs can be classified into energetic, time, risk and opportunity costs and may be levied directly or deferred during departure, transfer and settlement. They may equally be incurred during life stages before the actual dispersal event through investments in special morphologies. Because costs will eventually determine the performance of dispersing individuals and the evolution of dispersal, we here provide an extensive review on the different cost types that occur during dispersal in a wide array of organisms, ranging from micro‐organisms to plants, invertebrates and vertebrates. In general, costs of transfer have been more widely documented in actively dispersing organisms, in contrast to a greater focus on costs during departure and settlement in plants and animals with a p... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5233277 Mon, 19 Sep 2011 04:00:00 +0100 5233277 http://www.medworm.com/index.php?rid=5301698&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00204.x Life‐history traits describe parameters associated with growth, size, survival, and reproduction. Life‐history variation is a hallmark of biological diversity, yet researchers commonly observe that one of the major axes of life‐history variation after controlling for body size involves trade‐offs among growth, reproduction, and longevity. This persistent pattern of covariation among these specific traits has engendered a search for shared mechanisms that could constrain or facilitate production of variation in life‐history strategies. Endocrine traits are one candidate mechanism that may underlie the integration of life history and other phenotypic traits. However, the vast majority of this research has been on the effects of steroid hormones such as glucocorticoids and androgens... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5301698 Mon, 01 Aug 2011 04:00:00 +0100 5301698 http://www.medworm.com/index.php?rid=5246113&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00200.x The social amoebozoans have a life tricycle consisting of asexual multicellular development leading to fruiting bodies, sexual multicellular development resulting in macrocysts, and unicellular development generating microcysts. This review covers the events of sexual development in the best‐studied heterothallic (Dictyostelium discoideum) and homothallic (D. mucoroides) mating systems. Sexual development begins with pheromonal interactions that produce fusion‐competent cells (gametes) which undergo cell and pronuclear fusion. Calcium‐ and calmodulin‐mediated signalling mediates these early events. As they initiate chemotactic signalling, each zygote increases in size becoming a zygote giant cell. Using cyclic AMP (cAMP), the zygote chemotactically lures in amoebae and engulfs them... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5246113 Mon, 01 Aug 2011 04:00:00 +0100 5246113 http://www.medworm.com/index.php?rid=5233276&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00202.x In conclusion, some aspects of New Zealand's vegetation seem less unusual with increased knowledge, but others remain ‘problems’. (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5233276 Mon, 01 Aug 2011 04:00:00 +0100 5233276 http://www.medworm.com/index.php?rid=5155508&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00196.x Recalling the evolutionary sequence of development first of gonad and subsequently of oviducts, ovarian endocrine regulation of all known components of oviduct physiology is reviewed. Ovaries not only influence oviducts via the systemic blood circulation, but also locally by counter‐current transfer of relatively high concentrations of steroid hormones and prostaglandins between the ovarian vein and oviduct branch of the ovarian artery. The efficiency and impact of such counter‐current transfer is greatest around the time of ovulation, the transfer process receiving further inputs from hormones present in peritoneal fluid. Classical oviduct physiology is summarised, and the potential molecular consequences of temperature gradients within the duct lumen examined.At ovulation, an oocyte�... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5155508 Sun, 31 Jul 2011 23:00:00 +0100 5155508 http://www.medworm.com/index.php?rid=5102701&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00195.x Since the first mention of fetal programming of adult health and disease, a plethora of programming events in early life has been suggested. These have included intrauterine and postnatal events, but limited attention has been given to the potential contribution of the birth process to normal physiology and long‐term health. Over the last 30 years a growing number of studies have demonstrated that babies born at term by vaginal delivery (VD) have significantly different physiology at birth to those born by Caesarean section (CS), particularly when there has been no exposure to labour, i.e. pre‐labour CS (PLCS). This literature is reviewed here and the processes involved in VD that might programme post‐natal development are discussed. Some of the effects of CS are short term, but long... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5102701 Sun, 31 Jul 2011 23:00:00 +0100 5102701 http://www.medworm.com/index.php?rid=5085173&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00194.x In conclusion, the potential importance of measure theory in biological sciences in considered. (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5085173 Sun, 31 Jul 2011 23:00:00 +0100 5085173 http://www.medworm.com/index.php?rid=5068491&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00193.x Delayed plumage maturation is the delayed acquisition of a definitive colour and pattern of plumage until after the first potential breeding period in birds. Here we provide a comprehensive overview of the numerous studies of delayed plumage maturation and a revised theoretical framework for understanding the function of delayed plumage maturation in all birds. We first distinguish between hypotheses that delayed plumage maturation is attributable to a moult constraint with no adaptive function and hypotheses that propose that delayed plumage maturation is a component of an adaptive life‐history strategy associated with delayed reproductive investment. We then recognize three potential benefits of delayed plumage maturation: crypsis, mimicry and status signaling. Evidence suggests that d... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5068491 Wed, 27 Jul 2011 15:25:43 +0100 5068491 http://www.medworm.com/index.php?rid=5057215&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00192.x Humans have a dual nature. We are subject to the same natural laws and forces as other species yet dominate global ecology and exhibit enormous variation in energy use, cultural diversity, and apparent social organization. We suggest scientists tackle these challenges with a macroecological approach—using comparative statistical techniques to identify deep patterns of variation in large datasets and to test for causal mechanisms. We show the power of a metabolic perspective for interpreting these patterns and suggesting possible underlying mechanisms, one that focuses on the exchange of energy and materials within and among human societies and with the biophysical environment. Examples on human foraging ecology, life history, space use, population structure, disease ecology, cultural and... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5057215 Sun, 24 Jul 2011 04:18:25 +0100 5057215 http://www.medworm.com/index.php?rid=4951254&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00186.x Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosine (A) to inosine (I) in nuclear‐encoded RNAs and viral RNAs. The activity of ADARs has been demonstrated to be essential in mammals and serves to fine‐tune different proteins and modulate many molecular pathways. Recent findings have shown that ADAR activity is altered in many pathological tissues. Moreover, it has been shown that modulation of RNA editing is important for cell proliferation and migration, and has a protective effect on ischaemic insults. This review summarises available recent knowledge on A‐to‐I RNA editing and ADAR enzymes, with particular attention given to the emerging role played by these enzymes in cancer, some infectious diseases and immune‐mediated disorders. (Source: Biological ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4951254 Sun, 19 Jun 2011 23:00:00 +0100 4951254 http://www.medworm.com/index.php?rid=4891468&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00184.x There is a trend world‐wide to grow crops in short rotation or in monoculture, particularly in conventional agriculture. This practice is becoming more prevalent due to a range of factors including economic market trends, technological advances, government incentives, and retailer and consumer demands. Land‐use intensity will have to increase further in future in order to meet the demands of growing crops for both bioenergy and food production, and long rotations may not be considered viable or practical. However, evidence indicates that crops grown in short rotations or monoculture often suffer from yield decline compared to those grown in longer rotations or for the first time. Numerous factors have been hypothesised as contributing to yield decline, including biotic factors such as ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4891468 Tue, 31 May 2011 23:00:00 +0100 4891468 http://www.medworm.com/index.php?rid=5017723&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00191.x Among anuran amphibians (frogs and toads), there are two types of polyandry: simultaneous polyandry, where sperm from multiple males compete to fertilize eggs, and sequential polyandry, where eggs from a single female are fertilized by multiple males in a series of temporally separate mating events, and sperm competition is absent. Here we review the occurrence of sequential polyandry in anuran amphibians, outline theoretical explanations for the evolution of this mating system and discuss potential evolutionary implications. Sequential polyandry has been reported in a limited number of anurans, but its widespread taxonomic and geographic distribution suggests it may be common. There have been no empirical studies that have explicitly investigated the evolutionary consequences of sequentia... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5017723 Sat, 30 Apr 2011 23:00:00 +0100 5017723 http://www.medworm.com/index.php?rid=5006241&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00190.x Pneumatic (air‐filled) postcranial bones are unique to birds among extant tetrapods. Unambiguous skeletal correlates of postcranial pneumaticity first appeared in the Late Triassic (approximately 210 million years ago), when they evolved independently in several groups of bird‐line archosaurs (ornithodirans). These include the theropod dinosaurs (of which birds are extant representatives), the pterosaurs, and sauropodomorph dinosaurs. Postulated functions of skeletal pneumatisation include weight reduction in large‐bodied or flying taxa, and density reduction resulting in energetic savings during foraging and locomotion. However, the influence of these hypotheses on the early evolution of pneumaticity has not been studied in detail previously. We review recent work on the significanc... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=5006241 Sat, 30 Apr 2011 23:00:00 +0100 5006241 http://www.medworm.com/index.php?rid=4974565&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00189.x Letendre, Fincher & Thornhill (2010) argue that pathogen intensity provides the ultimate explanation for why some countries are more prone to civil war than others. They argue that the economic and political factors highlighted in previous research on civil war are largely caused by underlying differences in pathogen intensity, and contend that disease proneness increases the risk of civil war through its effects on resource competition and xenophobia. They present empirical evidence that they interpret as consistent with their argument: a statistically significant correlation between pathogen intensity and civil war onset. In this comment, we raise concerns over their interpretation of the empirical evidence and their proposed causal mechanisms. We find that the data provide stronger ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4974565 Sat, 30 Apr 2011 23:00:00 +0100 4974565 http://www.medworm.com/index.php?rid=4959222&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00187.x Understanding how communities of living organisms assemble has been a central question in ecology since the early days of the discipline. Disentangling the different processes involved in community assembly is not only interesting in itself but also crucial for an understanding of how communities will behave under future environmental scenarios. The traditional concept of assembly rules reflects the notion that species do not co‐occur randomly but are restricted in their co‐occurrence by interspecific competition. This concept can be redefined in a more general framework where the co‐occurrence of species is a product of chance, historical patterns of speciation and migration, dispersal, abiotic environmental factors, and biotic interactions, with none of these processes being mutual... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4959222 Sat, 30 Apr 2011 23:00:00 +0100 4959222 http://www.medworm.com/index.php?rid=4951253&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00188.x The evolution of endothermy in birds and mammals was one of the most important events in the evolution of the vertebrates. Past tests of hypotheses on the evolution of endothermy in mammals have relied largely on analyses of the relationship between basal and maximum metabolic rate, and artificial selection experiments. I argue that components of existing hypotheses, as well as new hypotheses, can be tested using an alternative macrophysiological modeling approach by examining the development of endothermy during the Cenozoic. Recent mammals display a 10°C range in body temperature which is sufficiently large to identify the selective forces that have driven the development of endothermy from a plesiomorphic (ancestral) Cretaceous or Jurassic condition. A model is presented (the Plesiomor... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4951253 Sat, 30 Apr 2011 23:00:00 +0100 4951253 http://www.medworm.com/index.php?rid=4891467&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00185.x Large mammalian herbivores manifest a strong top‐down control on ecosystems that can transform entire landscapes, but their impacts have not been reviewed in the context of terrestrial carbon storage. Here, we evaluate the effects of plant biomass consumption by large mammalian herbivores (>10 kg adult biomass), and the responses of ecosystems to these herbivores, on carbon stocks in temperate and tropical regions, and the Arctic. We calculate the difference in carbon stocks resulting from herbivore exclusion using the results of 108 studies from 52 vegetation types. Our estimates suggest that herbivores can reduce terrestrial above‐ and below‐ground carbon stocks across vegetation types but reductions in carbon stocks may approach zero given sufficient periods of time for systems... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4891467 Sat, 30 Apr 2011 23:00:00 +0100 4891467 http://www.medworm.com/index.php?rid=4811882&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00183.x In recent decades we have seen rapid and co‐occurring changes in landscape structure, species distributions and even climate as consequences of human activity. Such changes affect the dynamics of the interaction between major forest pest species, such as bark beetles (Coleoptera: Curculionidae, Scolytinae), and their host trees. Normally breeding mostly in broken or severely stressed spruce; at high population densities some bark beetle species can colonise and kill healthy trees on scales ranging from single trees in a stand to multi‐annual landscape‐wide outbreaks. In Eurasia, the largest outbreaks are caused by the spruce bark beetle, Ips typographus (Linnaeus), which is common and shares a wide distribution with its main host, Norway spruce (Picea abies Karst.). A large literatur... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4811882 Sat, 30 Apr 2011 23:00:00 +0100 4811882 http://www.medworm.com/index.php?rid=4788077&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00182.x The consequences of polyandry for female fitness are controversial. Sexual conflict studies and a meta‐analysis of mating rates in insects suggest that there is a longevity cost when females mate repeatedly. Even so, compensatory material benefits can elevate egg production and fertility, partly because polyandry ensures an adequate sperm supply. Polyandry can therefore confer direct benefits. The main controversy surrounds genetic benefits. The argument is analogous to that surrounding the evolution of conventional female mate choice, except that with polyandry it is post‐copulatory mechanisms that might bias paternity towards males with higher breeding values for fitness. Recent meta‐analyses of extra‐pair copulations in birds have cast doubt on whether detectable genetic benefit... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4788077 Sat, 30 Apr 2011 23:00:00 +0100 4788077 http://www.medworm.com/index.php?rid=4731945&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00181.x Teeth are brittle and highly susceptible to cracking. We propose that observations of such cracking can be used as a diagnostic tool for predicting bite force and inferring tooth function in living and fossil mammals. Laboratory tests on model tooth structures and extracted human teeth in simulated biting identify the principal fracture modes in enamel. Examination of museum specimens reveals the presence of similar fractures in a wide range of vertebrates, suggesting that cracks extended during ingestion or mastication. The use of ‘fracture mechanics' from materials engineering provides elegant relations for quantifying critical bite forces in terms of characteristic tooth size and enamel thickness. The role of enamel microstructure in determining how cracks initiate and propagate withi... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4731945 Wed, 20 Apr 2011 14:02:01 +0100 4731945 http://www.medworm.com/index.php?rid=4718898&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00178.x We present a complete phylogeny of macroperforate planktonic foraminifer species of the Cenozoic Era (∼65 million years ago to present). The phylogeny is developed from a large body of palaeontological work that details the evolutionary relationships and stratigraphic (time) distributions of species‐level taxa identified from morphology (‘morphospecies’). Morphospecies are assigned to morphogroups and ecogroups depending on test morphology and inferred habitat, respectively. Because gradual evolution is well documented in this clade, we have identified many instances of morphospecies intergrading over time, allowing us to eliminate ‘pseudospeciation’ and ‘pseudoextinction’ from the record and thereby permit the construction of a more natural phylogeny based on inferred biol... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4718898 Sat, 16 Apr 2011 05:54:54 +0100 4718898 http://www.medworm.com/index.php?rid=4708622&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00179.x Recent shifts in phenology in response to climate change are well established but often poorly understood. Many animals integrate climate change across a spatially and temporally dispersed annual life cycle, and effects are modulated by ecological interactions, evolutionary change and endogenous control mechanisms. Here we assess and discuss key statements emerging from the rapidly developing study of changing spring phenology in migratory birds. These well‐studied organisms have been instrumental for understanding climate‐change effects, but research is developing rapidly and there is a need to attack the big issues rather than risking affirmative science. Although we agree poorly on the support for most claims, agreement regarding the knowledge basis enables consensus regarding broad... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4708622 Thu, 14 Apr 2011 04:34:03 +0100 4708622 http://www.medworm.com/index.php?rid=4708623&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00180.x Regulated use of exons in pre‐mRNAs, a process known as alternative splicing, strongly contributes to proteome diversity. Alternative splicing is finely regulated by factors that bind specific sequences within the precursor mRNAs. Members of the Muscleblind (Mbl) family of splicing factors control critical exon use changes during the development of specific tissues, particularly heart and skeletal muscle. Muscleblind homologs are only found in metazoans from Nematoda to mammals. Splicing targets and recognition mechanisms are also conserved through evolution. In this recognition, Muscleblind CCCH‐type zinc finger domains bind to intronic motifs in pre‐mRNA targets in which the protein can either activate or repress splicing of nearby exons, depending on the localization of the bindin... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4708623 Tue, 12 Apr 2011 23:00:00 +0100 4708623 http://www.medworm.com/index.php?rid=4651943&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00177.x During the last decade, coat colouration in mammals has been investigated in numerous studies. Most of these studies addressing the genetics of coat colouration were on domesticated animals. In contrast to their wild ancestors, domesticated species are often characterized by a huge allelic variability of coat‐colour‐associated genes. This variability results from artificial selection accepting negative pleiotropic effects linked with certain coat‐colour variants. Recent studies demonstrate that this selection for coat‐colour phenotypes started at the beginning of domestication. Although to date more than 300 genetic loci and more than 150 identified coat‐colour‐associated genes have been discovered, which influence pigmentation in various ways, the genetic pathways influencing ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4651943 Tue, 01 Feb 2011 00:00:00 +0100 4651943 http://www.medworm.com/index.php?rid=4614638&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00176.x High‐crowned (hypsodont) teeth are widely found among both extant and extinct mammalian herbivores. Extant grazing ungulates (hoofed mammals) have hypsodont teeth (a derived condition), and so extinct hypsodont forms have usually been presumed to have been grazers. Thus, hypsodonty among ungulates has, over the past 150 years, formed the basis of widespread palaeoecological interpretations, and has figured prominently in the evolutionary study of the spread of grasslands in the mid Cenozoic. However, perceived inconsistencies between levels of hypsodonty and dental wear patterns in both extant and extinct ungulates have caused some workers to reject hypsodonty as a useful predictive tool in palaeobiology, a view that we consider both misguided and premature.Despite the acknowledged assoc... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4614638 Tue, 01 Feb 2011 00:00:00 +0100 4614638 http://www.medworm.com/index.php?rid=4605194&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00175.x Multiple mating or group spawning leads to post‐copulatory sexual selection, which generally favours ejaculates that are more competitive under sperm competition. In four meta‐analyses we quantify the evidence that sperm competition (SC) favours greater sperm number using data from studies of strategic ejaculation. Differential investment into each ejaculate emerges at the individual level if males exhibit phenotypic plasticity in ejaculate properties in response to the likely risk and/or intensity of sperm competition after a given mating. Over the last twenty years, a series of theoretical models have been developed that predict how ejaculate size will be strategically adjusted in relation to: (a) the number of immediate rival males, with a distinction made between 0 versus 1 rival (... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4605194 Tue, 01 Feb 2011 00:00:00 +0100 4605194 http://www.medworm.com/index.php?rid=4476928&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2011.00174.x A central goal in Life Sciences is to understand how genes encode behaviour and how environmental factors influence the expression of the genes concerned. To reach this goal a combined ecological, molecular biological and physiological approach is required in combination with a suitable model organism. Such an approach allows the elucidation of all parts of the complicated chain of events that lead from induction of gene expression to behaviour, i.e. from environmental stimulus, sensory organs and extracellular and intracellular neuronal signal processing to activation of effector organs. A particularly good model species with which to take this approach is the nematode Caenorhabditis elegans, as it has been described in great detail at the genomic, cellular and behavioural levels. Differe... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4476928 Tue, 01 Feb 2011 00:00:00 +0100 4476928 http://www.medworm.com/index.php?rid=4336979&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00173.x Avian parents and social insect colonies are victimized by interspecific brood parasites—cheats that procure costly care for their dependent offspring by leaving them in another species' nursery. Birds and insects defend themselves from attack by brood parasites; their defences in turn select counter‐strategies in the parasite, thus setting in motion antagonistic co‐evolution between the two parties. Despite their considerable taxonomic disparity, here we show striking parallels in the way that co‐evolution between brood parasites and their hosts proceeds in insects and birds. First, we identify five types of co‐evolutionary arms race from the empirical literature, which are common to both systems. These are: (a) directional co‐evolution of weaponry and armoury; (b) furtiveness... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4336979 Wed, 12 Jan 2011 00:00:00 +0100 4336979 http://www.medworm.com/index.php?rid=4308907&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00172.x A life‐history trade‐off exists between flight capability and reproduction in many wing dimorphic insects: a long‐winged morph is flight‐capable at the expense of reproduction, while a short‐winged morph cannot fly, is less mobile, but has greater reproductive output. Using meta‐analyses, I investigated specific questions regarding this trade‐off. The trade‐off in females was expressed primarily as a later onset of egg production and lower fecundity in long‐winged females relative to short‐winged females. Although considerably less work has been done with males, the trade‐off exists for males among traits primarily related to mate acquisition. The trade‐off can potentially be mitigated in males, as long‐winged individuals possess an advantage in traits that can of... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4308907 Tue, 04 Jan 2011 00:00:00 +0100 4308907 http://www.medworm.com/index.php?rid=4287191&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00170.x The metapleural gland (MG) is a complex glandular structure unique to ants, suggesting a critical role in their origin and ecological success. We synthesize the current understanding of the adaptive function, morphology, evolutionary history, and chemical properties of the MG. Two functions of the MG, sanitation and chemical defence, have received the strongest empirical support; two additional possible functions, recognition odour and territorial marking, are less well supported. The design of the MG is unusual for insects; glandular secretions are stored in a rigid, non‐compressible invagination of the integument and the secretion is thought to ooze out passively through the non‐closable opening of the MG or is groomed off by the legs and applied to target surfaces. MG loss has occur... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4287191 Fri, 24 Dec 2010 00:00:00 +0100 4287191 http://www.medworm.com/index.php?rid=4257902&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00171.x One of the oldest challenges in ecology is to understand the processes that underpin the composition of communities. Historically, an obvious way in which to describe community compositions has been diversity in terms of the number and abundances of species. However, the failure to reject contradictory models has led to communities now being characterized by trait and phylogenetic diversities. Our objective here is to demonstrate how species, trait and phylogenetic diversity can be combined together from large to local spatial scales to reveal the historical, deterministic and stochastic processes that impact the compositions of local communities. Research in this area has recently been advanced by the development of mathematical measures that incorporate trait dissimilarities and phylogen... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4257902 Tue, 14 Dec 2010 00:00:00 +0100 4257902 http://www.medworm.com/index.php?rid=4158334&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00168.x Geographical and temporal variations in body size are common phenomena among organisms and may evolve within a few years. We argue that body size acts much like a barometer, fluctuating in parallel with changes in the relevant key predictor(s), and that geographical and temporal changes in body size are actually manifestations of the same drivers. Frequently, the principal predictors of body size are food availability during the period of growth and ambient temperature, which often affects food availability. Food availability depends on net primary productivity that, in turn, is determined by climate and weather (mainly temperature and precipitation), and these depend mainly on solar radiation and other solar activities. When the above predictors are related to latitude the changes have of... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4158334 Thu, 11 Nov 2010 00:00:00 +0100 4158334 http://www.medworm.com/index.php?rid=4149715&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00163.x Foraging theory was first developed to predict the behaviour of widely‐foraging animals that actively search for prey. Although the behaviour of sit‐and‐wait predators often follows predictions derived from foraging theory, the similarity between these two distinct groups of predators is not always obvious. In this review, we compare foraging activities of trap‐building predators (mainly pit‐building antlions and web‐building spiders), a specific group of sit‐and‐wait predators that construct traps as a foraging device, with those of widely‐foraging predators. We refer to modifications of the trap characteristics as analogous to changes in foraging intensity. Our review illustrates that the responses of trap‐building and widely‐foraging predators to different internal... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4149715 Wed, 10 Nov 2010 00:00:00 +0100 4149715 http://www.medworm.com/index.php?rid=4189210&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00169.x There has been considerable interest among biologists in the phenomenon of non‐human animal personality in recent years. Consistent variations among individuals in their behavioural responses to ecologically relevant stimuli, often relating to a trade‐off between level of risk and reward, have been recorded in a wide variety of species, representing many animal taxa. Research into behavioural variation among individuals has major implications for our understanding of ecological patterns and processes at scales from the level of the individual to the level of the population. Until recently, however, many studies that have considered the broader ecological implications of animal personality have failed to take into account the crucial moderating effect of social context. It is well docum... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4189210 Mon, 01 Nov 2010 00:00:00 +0100 4189210 http://www.medworm.com/index.php?rid=4166970&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00167.x The group selection debate of the 1960s made it clear that evolution does not necessarily increase population performance. Individuals can be selected to have traits that diminish a common good and make population persistence difficult. At the extreme, the discrepancy between levels of selection is predicted to make traits evolve towards values at which a population can no longer persist (evolutionary suicide). Dispersal and prospecting are prime examples of traits that have a strong influence on population persistence under environmental and demographic stochasticity. Theory predicts that an ‘optimal’ dispersal strategy from a population point of view can differ considerably from that produced by individual‐level selection. Because dispersal is frequently risky or otherwise costly, ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4166970 Mon, 01 Nov 2010 00:00:00 +0100 4166970 http://www.medworm.com/index.php?rid=4158333&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00165.x The transition from wakefulness to sleep is marked by pronounced changes in brain activity. The brain rhythms that characterize the two main types of mammalian sleep, slow‐wave sleep (SWS) and rapid eye movement (REM) sleep, are thought to be involved in the functions of sleep. In particular, recent theories suggest that the synchronous slow‐oscillation of neocortical neuronal membrane potentials, the defining feature of SWS, is involved in processing information acquired during wakefulness. According to the Standard Model of memory consolidation, during wakefulness the hippocampus receives input from neocortical regions involved in the initial encoding of an experience and binds this information into a coherent memory trace that is then transferred to the neocortex during SWS where it... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4158333 Mon, 01 Nov 2010 00:00:00 +0100 4158333 http://www.medworm.com/index.php?rid=4149714&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00166.x Parents affect offspring fitness by propagule size and quality, selection of oviposition site, quality of incubation, feeding of dependent young, and their defence against predators and parasites. Despite many case studies on each of these topics, this knowledge has not been rigorously integrated into individual parental care traits for any taxon. Consequently, we lack a comprehensive, quantitative assessment of how parental care modifies offspring phenotypes. This meta‐analysis of 283 studies with 1805 correlations between egg size and offspring quality in birds is intended to fill this gap. The large sample size enabled testing of how the magnitude of the relationship between egg size and offspring quality depends on a number of variables. Egg size was positively related to nearly all ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4149714 Mon, 01 Nov 2010 00:00:00 +0100 4149714 http://www.medworm.com/index.php?rid=4116965&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00164.x The initial response of individuals to human‐induced environmental change is often behavioural. This can improve the performance of individuals under sudden, large‐scale perturbations and maintain viable populations. The response can also give additional time for genetic changes to arise and, hence, facilitate adaptation to new conditions. On the other hand, maladaptive responses, which reduce individual fitness, may occur when individuals encounter conditions that the population has not experienced during its evolutionary history, which can decrease population viability. A growing number of studies find human disturbances to induce behavioural responses, both directly and by altering factors that influence fitness. Common causes of behavioural responses are changes in the transmission... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4116965 Sat, 30 Oct 2010 00:33:16 +0100 4116965 http://www.medworm.com/index.php?rid=4104727&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00157.x Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical techniques available to biology. This review is an introduction to the potential of this method and is aimed at readers who have little or no experience in acquiring or analyzing NMR spectra. We focus on spectroscopic applications of the magnetic resonance effect, rather than imaging ones, and explain how various aspects of the NMR phenomenon make it a versatile tool with which to address a number of biological problems. Using detailed examples, we discuss the use of 1 (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4104727 Tue, 26 Oct 2010 10:05:07 +0100 4104727 http://www.medworm.com/index.php?rid=4081281&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00159.x Recent high‐profile calls for a more trait‐focused approach to community ecology have the potential to open up novel research areas, generate new insights and to transform community ecology into a more predictive science. However, a renewed emphasis on function and phenotype also requires a fundamental shift in approach and research philosophy within community ecology to more fully embrace evolutionary reasoning. Such a subject‐wise transformation will be difficult due to at least four factors: (1) the historical development of the academic discipline of ecology and its roots as a descriptive science; (2) the dominating role of the ecosystem concept in the driving of contemporary ecological thought; (3) the practical difficulties associated with defining and identifying (phenotypic) ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4081281 Tue, 19 Oct 2010 19:29:42 +0100 4081281 http://www.medworm.com/index.php?rid=4072875&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00162.x The fossil record of the Hippopotamidae can shed light on three major issues in mammalian evolution. First, as the Hippopotamidae are the extant sister group of Cetacea, gaining a better understanding of the origin of the Hippopotamidae and of their Paleogene ancestors will be instrumental in clarifying phylogenetic relationships within Cetartiodactyla. Unfortunately, the data relevant to hippopotamid origins have generally been ignored in phylogenetic analyses of cetartiodactyls. In order to obtain better resolution, future analyses should consider hypotheses of hippopotamid Paleogene relationships. Notably, an emergence of the Hippopotamidae from within anthracotheriids has received growing support, leading to reconciliation between genetic and morphological evidence for the clade Cetanc... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4072875 Sat, 16 Oct 2010 15:35:45 +0100 4072875 http://www.medworm.com/index.php?rid=4035637&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00160.x Several attempts have been made in recent years to formulate a general explanation for what appear to be recurring patterns of allometric variation in morphology, physiology, and ecology of both plants and animals (e.g. (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4035637 Thu, 30 Sep 2010 23:00:00 +0100 4035637 http://www.medworm.com/index.php?rid=3975990&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00154.x Cancer is controlled not only by genetic events but also by epigenetic events. The active acquisition of epigenetic changes is a poorly understood but very important process in mammalian development, differentiation, and disease. It is well established that epigenetic events are controlled by a specific subgroup of proteins, such as DNA methyltransferases, histone acetylases histone lysine methyltransferases or histone deacetylases, that influence methylation or acetylation patterns to modulate gene expression. We and others have identified S‐adenosylhomocysteine hydrolase in a high‐throughput genetic screen focused on discovering novel genes whose inhibition induces immortalisation of primary cells. Herein, we address the importance of genes involved in epigenetic mechanisms during se... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3975990 Tue, 31 Aug 2010 23:00:00 +0100 3975990 http://www.medworm.com/index.php?rid=3975989&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00158.x The conundrum of why subordinate individuals assist dominants at the expense of their own direct reproduction has received much theoretical and empirical attention over the last 50 years. During this time, birds and mammals have taken centre stage as model vertebrate systems for exploring why helpers help. However, fish have great potential for enhancing our understanding of the generality and adaptiveness of helping behaviour because of the ease with which they can be experimentally manipulated under controlled laboratory and field conditions. In particular, the freshwater African cichlid, Neolamprologus pulcher, (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3975989 Tue, 31 Aug 2010 23:00:00 +0100 3975989 http://www.medworm.com/index.php?rid=3822349&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00152.x We present a series of testable predictions from these models that arise from the interplay over time among three exotic plant traits (growth form, area of coverage, taxonomic distinctiveness) and six traits of reptiles and amphibians (body size, lifespan, home range size, habitat specialisation, diet, reproductive strategy). A literature review provided robust empirical evidence of exotic plant impacts on reptiles and amphibians from each of the three model mechanisms. Evidence relating to the role of body size and diet was less clear-cut, indicating the need for further research. The literature provided limited empirical support for many of the other model predictions. This was not, however, because findings contradicted our model predictions but because research in this area is sparse. ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3822349 Wed, 04 Aug 2010 23:00:00 +0100 3822349 http://www.medworm.com/index.php?rid=3812203&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00148.x Zooplankton is a morphologically and taxonomically diverse group and includes organisms that vary in size by many orders of magnitude, but they are all faced with the common problem of collecting food from a very dilute suspension. In order to maintain a viable population in the face of mortality, zooplankton in the ocean have to clear daily a volume of ambient water for prey particles that is equivalent to about 106 times their own body volume. While most size-specific vital rates and mortality rates decline with size, the clearance requirement is largely size-independent because food availability also declines with size. There is a limited number of solutions to the problem of concentrating dilute prey from a sticky medium: passive and active ambush feeding; feeding-current feeding, wher... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3812203 Mon, 02 Aug 2010 23:00:00 +0100 3812203 http://www.medworm.com/index.php?rid=4035636&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00161.x Muscle fibres have different properties with respect to force, contraction speed, endurance, oxidative/glycolytic capacity etc. Although adult muscle fibres are normally post‐mitotic with little turnover of cells, the physiological properties of the pre‐existing fibres can be changed in the adult animal upon changes in usage such as after exercise. The signal to change is mainly conveyed by alterations in the patterns of nerve‐evoked electrical activity, and is to a large extent due to switches in the expression of genes. Thus, an excitation‐transcription coupling must exist. It is suggested that changes in nerve‐evoked muscle activity lead to a variety of activity correlates such as increases in free intracellular Ca2+ (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=4035636 Sat, 31 Jul 2010 23:00:00 +0100 4035636 http://www.medworm.com/index.php?rid=3975988&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00155.x Developing high‐quality scientific research will be most effective if research communities with diverse skills and interests are able to share information and knowledge, are aware of the major challenges across disciplines, and can exploit economies of scale to provide robust answers and better inform policy. We evaluate opportunities and challenges facing the development of a more interactive research environment by developing an interdisciplinary synthesis of research on a single geographic region. We focus on the Amazon as it is of enormous regional and global environmental importance and faces a highly uncertain future. To take stock of existing knowledge and provide a framework for analysis we present a set of mini‐reviews from fourteen different areas of research, encompassing ta... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3975988 Sat, 31 Jul 2010 23:00:00 +0100 3975988 http://www.medworm.com/index.php?rid=3968526&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00156.x The role of ecology in the evolution and maintenance of arthropod sociality has received increasing research attention in recent years. In some organisms, such as halictine bees, polistine wasps, and social spiders, researchers are investigating the environmental factors that may contribute to high levels of variation in the degree of sociality exhibited both among and within species. Within lineages that include only eusocial members, such as ants and termites, studies focus more on identifying extrinsic factors that may contribute to the dramatic variation in colony size, number of queens, and division of labour that is evident across these species. In this review, I propose a comparative approach that seeks to identify environmental factors that may have a common influence across such d... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3968526 Sat, 31 Jul 2010 23:00:00 +0100 3968526 http://www.medworm.com/index.php?rid=3871848&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00151.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3871848 Sat, 31 Jul 2010 23:00:00 +0100 3871848 http://www.medworm.com/index.php?rid=3868516&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00153.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3868516 Sat, 31 Jul 2010 23:00:00 +0100 3868516 http://www.medworm.com/index.php?rid=3841873&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00119.x Dispersal has recently gained much attention because of its crucial role in the conservation and evolution of species facing major environmental changes such as habitat loss and fragmentation, climate change, and their interactions. Butterflies have long been recognized as ideal model systems for the study of dispersal and a huge amount of data on their ability to disperse has been collected under various conditions. However, no single ‘best’ method seems to exist leading to the co‐occurrence of various approaches to study butterfly mobility, and therefore a high heterogeneity among data on dispersal across this group. Accordingly, we here reviewed the knowledge accumulated on dispersal and mobility in butterflies, to detect general patterns. This meta‐analysis specifically address... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841873 Sat, 31 Jul 2010 23:00:00 +0100 3841873 http://www.medworm.com/index.php?rid=3841872&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00112.x This review describes recent developments in analysing the influence of radio‐frequency electromagnetic fields (RF‐EMFs ) on biological systems by monitoring the cellular stress response as well as overall gene expression. Recent data on the initiation and modulation of the classical cellular stress response by RF‐EMFs, comprising expression of heat shock proteins and stimulation of stress‐activated protein kinases, are summarised and evaluated. Since isothermic RF‐EMF exposure is assumed rather than proven there are clear limitations in using the stress response to describe non‐thermal effects of RF‐EMFs. In particular, further experiments are needed to characterise better the threshold of the thermal heat shock response and the homogeneity of the cellular response in the wh... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841872 Sat, 31 Jul 2010 23:00:00 +0100 3841872 http://www.medworm.com/index.php?rid=3841871&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00106.x Conservation objectives for non‐breeding coastal birds (shorebirds and wildfowl) are determined from their population size at coastal sites. To advise coastal managers, models must predict quantitatively the effects of environmental change on population size or the demographic rates (mortality and reproduction) that determine it. As habitat association models and depletion models are not able to do this, we developed an approach that has produced such predictions thereby enabling policy makers to make evidence‐based decisions. Our conceptual framework is individual‐based ecology, in which populations are viewed as having properties (e.g. size) that arise from the traits (e.g. behaviour, physiology) and interactions of their constituent individuals. The link between individuals and po... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841871 Sat, 31 Jul 2010 23:00:00 +0100 3841871 http://www.medworm.com/index.php?rid=3790118&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00150.x The spectacular diversity in sexually selected traits in the animal kingdom has inspired the hypothesis that sexual selection can promote species divergence. In recent years, several studies have attempted to test this idea by correlating species richness with estimates of sexual selection across phylogenies. These studies have yielded mixed results and it remains unclear whether the comparative evidence can be taken as generally supportive. Here, we conduct a meta-analysis of the comparative evidence and find a small but significant positive overall correlation between sexual selection and speciation rate. However, we also find that effect size estimates are influenced by methodological choices. Analyses that included deeper phylogenetic nodes yielded weaker correlations, and different pr... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3790118 Mon, 26 Jul 2010 23:00:00 +0100 3790118 http://www.medworm.com/index.php?rid=3757235&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00149.x We report that female competition is associated with many diverse adaptations, from overtly aggressive behaviour, weaponry, and conspicuous sexual signals to subtle and often complex social behaviour involving olfactory signalling, alliance formation, altruism and spite, and even cases where individuals appear to inhibit their own reproduction. Overall, despite some obvious parallels with male phenotypic traits favoured under sexual selection, it appears that fundamental differences in the reproductive strategies of the sexes (ultimately related to parental investment) commonly lead to contrasting competitive goals and adaptations. Because female adaptations for intrasexual competition are often less conspicuous than those of males, they are generally more challenging to study. In particul... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3757235 Thu, 15 Jul 2010 23:00:00 +0100 3757235 http://www.medworm.com/index.php?rid=3721383&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00147.x Sperm are often considered to be individuals, in part because of their unique genetic identities produced as a result of synapsis during meiosis, and in part due to their unique ecology, being ejected away from the soma to continue their existence in a foreign environment. Selection at the level of individual sperm has been suggested to explain the evolution of two enigmatic sperm phenotypes: sperm heteromorphism, where more than one type of sperm is produced by a male, and sperm conjugation, where multiple sperm join together for motility and transport through the female reproductive tract before dissociation prior to fertilization. In sperm heteromorphic species, only one of the sperm morphs typically participates in fertilization, with the non-fertilizing "parasperm" being interpreted a... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3721383 Fri, 02 Jul 2010 23:00:00 +0100 3721383 http://www.medworm.com/index.php?rid=3841863&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00148.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841863 Wed, 30 Jun 2010 23:00:00 +0100 3841863 http://www.medworm.com/index.php?rid=3721384&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00146.x The amount of energy allocated to growth versus other functions is a fundamental feature of an organism's life history. Constraints on energy availability result in characteristic trade-offs among life-history traits and reflect strategies by which organisms adapt to their environments. Freshwater mussels are a diverse and imperiled component of aquatic ecosystems but little is known about their growth and longevity. Generalized depictions of freshwater mussels as 'long-lived and slow-growing' may give an unrealistically narrow view of life-history diversity which is incongruent with the taxonomic diversity of the group and can result in development of inappropriate conservation strategies. We investigated relationships among growth, longevity, and size in 57 species and 146 populations of... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3721384 Wed, 30 Jun 2010 23:00:00 +0100 3721384 http://www.medworm.com/index.php?rid=3690346&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00145.x Although the primary function of mating is gamete transfer, male ejaculates contain numerous other substances that are produced by accessory glands and transferred to females during mating. Studies with several model organisms have shown that these substances can exert diverse behavioural and physiological effects on females, including altered longevity and reproductive output, yet a comprehensive synthesis across taxa is lacking. Here we use a meta-analytic approach to synthesize quantitatively extensive experimental work examining how male ejaculate quantity affects different components of female fitness. We summarize effect sizes for female fecundity (partial and lifetime) and longevity from 84 studies conducted on 70 arthropod species that yielded a total of 130 comparisons of female f... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3690346 Wed, 23 Jun 2010 23:00:00 +0100 3690346 http://www.medworm.com/index.php?rid=3683061&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00141.x Repeatability (more precisely the common measure of repeatability, the intra-class correlation coefficient, ICC) is an important index for quantifying the accuracy of measurements and the constancy of phenotypes. It is the proportion of phenotypic variation that can be attributed to between-subject (or between-group) variation. As a consequence, the non-repeatable fraction of phenotypic variation is the sum of measurement error and phenotypic flexibility. There are several ways to estimate repeatability for Gaussian data, but there are no formal agreements on how repeatability should be calculated for non-Gaussian data (e.g. binary, proportion and count data). In addition to point estimates, appropriate uncertainty estimates (standard errors and confidence intervals) and statistical signif... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3683061 Sun, 20 Jun 2010 23:00:00 +0100 3683061 http://www.medworm.com/index.php?rid=3665425&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00140.x Sperm competition was identified in 1970 as a pervasive selective force in post-copulatory sexual selection that occurs when the ejaculates of different males compete to fertilise a given set of ova. Since then, sperm competition has been much studied both empirically and theoretically. Because sperm competition often favours large ejaculates, an important challenge has been to understand the evolution of strategies through which males invest in sperm production and economise sperm allocation to maximise reproductive success under competitive conditions. Sperm competition mechanisms vary greatly, depending on many factors including the level of sperm competition, space constraints in the sperm competition arena, male mating roles, and female influences on sperm utilisation. Consequently, t... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3665425 Tue, 15 Jun 2010 23:00:00 +0100 3665425 http://www.medworm.com/index.php?rid=3647875&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00144.x A major evolutionary question is how reproductive sharing arises in cooperatively breeding species despite the inherent reproductive conflicts in social groups. Reproductive skew theory offers one potential solution: each group member gains or is allotted inclusive fitness equal to or exceeding their expectation from reproducing on their own. Unfortunately, a multitude of skew models with conflicting predictions has led to confusion in both testing and evaluating skew theory. The confusion arises partly because one set of models (the 'transactional' type) answer the ultimate evolutionary question of what ranges of reproductive skew can yield fitness-enhancing solutions for all group members. The second set of models ('compromise') give an evolutionarily proximate, game-theoretic evolutiona... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3647875 Wed, 09 Jun 2010 23:00:00 +0100 3647875 http://www.medworm.com/index.php?rid=3841866&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00141.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841866 Mon, 31 May 2010 23:00:00 +0100 3841866 http://www.medworm.com/index.php?rid=3841865&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00145.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841865 Mon, 31 May 2010 23:00:00 +0100 3841865 http://www.medworm.com/index.php?rid=3841864&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00147.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841864 Mon, 31 May 2010 23:00:00 +0100 3841864 http://www.medworm.com/index.php?rid=3602937&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00142.x In this study, the examination of the enamel microstructure of 28 additional dinosaur taxa fills in taxonomic gaps of previous studies and reinforces the aforementioned conclusions. Additionally, these new specimens reveal that within clades such as Sauropodomorpha, Neotheropoda, and Euornithopoda, the more basal taxa have simpler enamel that is a precursor to the more complex enamel of more derived taxa and that schmelzmusters evolve in a stepwise fashion. In the particularly well-sampled clade of Euornithopoda, correlations between the evolution of dental and enamel characters could be drawn. The ancestral schmelzmuster for Genasauria remains ambiguous due to the dearth of basal ornithischian teeth available for study. These new specimens provide new insights into the evolution of tooth ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3602937 Wed, 26 May 2010 23:00:00 +0100 3602937 http://www.medworm.com/index.php?rid=3602938&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00143.x Many herbivorous animals selectively eat flowers and unripe fruit or seeds. Some preferentially eat new tissues growing from germinating seeds. This behaviour enables access to otherwise limited or unavailable amino acids that are necessary to sustain successful production and growth of young. For the same reason the diet of breeding females and neonates of many presumed strictly herbivorous animals is supplemented with animal protein. However, because these foods are often only eaten for limited periods, and make up only a small proportion of the total diet, they are usually dismissed as unimportant to the animals' nutrition. It is suggested that actively looking for such feeding may well reveal it to be far more common and important to the successful breeding of herbivores than has been ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3602938 Tue, 25 May 2010 23:00:00 +0100 3602938 http://www.medworm.com/index.php?rid=3518733&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00137.x The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism. We review the biology of sauropod dinosaurs in detail and posit that sa... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3518733 Thu, 29 Apr 2010 23:00:00 +0100 3518733 http://www.medworm.com/index.php?rid=3479363&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00139.x The accurate reconstruction of palaeobiodiversity patterns is central to a detailed understanding of the macroevolutionary history of a group of organisms. However, there is increasing evidence that diversity patterns observed directly from the fossil record are strongly influenced by fluctuations in the quality of our sampling of the rock record; thus, any patterns we see may reflect sampling biases, rather than genuine biological signals. Previous dinosaur diversity studies have suggested that fluctuations in sauropodomorph palaeobiodiversity reflect genuine biological signals, in comparison to theropods and ornithischians whose diversity seems to be largely controlled by the rock record. Most previous diversity analyses that have attempted to take into account the effects of sampling bi... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3479363 Fri, 16 Apr 2010 23:00:00 +0100 3479363 http://www.medworm.com/index.php?rid=3471237&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00138.x Millipedes (Diplopoda) and woodlice (Crustacea, Isopoda), with a total of about 15000 described species worldwide, contribute substantially to invertebrate biodiversity. These saprophagous macroarthropods, which are key regulators of plant litter decomposition, play an important role in the functioning of terrestrial ecosystems in tropical and temperate areas. Herein we review current knowledge on the effects of climate, food quality and land cover on millipede and woodlouse species to explore their potential responses to global change. Essentially similar trends are observed in the two taxa. Experiments have shown that climate warming could result in higher rates of population growth and have positive effects on the abundance of some temperate species. This is consistent with signs of nor... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3471237 Wed, 14 Apr 2010 23:00:00 +0100 3471237 http://www.medworm.com/index.php?rid=3471238&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00135.x Superfetation is understood as another conception during an already ongoing pregnancy. This implies the existence of young of different developmental stages within the female reproductive tract during certain periods of pregnancy. Nevertheless, a clear definition of the term as well as distinct criteria to identify the occurrence of superfetation in a species is missing. The variable anatomy of mammalian reproductive tracts seems to make the occurrence of superfetation more or less likely but impedes the simple evaluation of whether it is present or not. Additionally, adequate determination methods are missing or are difficult to apply at the right time. Superfetation or rather superfetation-like pregnancies are reported for numerous species including humans, livestock and rodents. The usu... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3471238 Tue, 13 Apr 2010 23:00:00 +0100 3471238 http://www.medworm.com/index.php?rid=3459742&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00136.x According to life-history theory, growth rates are subject to strong directional selection due to reproductive and survival advantages associated with large adult body size. Yet, growth is commonly observed to occur at rates lower than the maximum that is physiologically possible and intrinsic growth rates often vary among populations. This implies that slower growth is favoured under certain conditions. Realized growth rate is thus the result of a compromise between the costs and advantages of growing rapidly, and the optimal rate of growth is not equivalent to the fundamental maximum rate. The ecological and evolutionary factors influencing growth rate are reviewed, with particular emphasis on how growth might be constrained by direct fitness costs. Costs of accelerating growth might con... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3459742 Sun, 11 Apr 2010 23:00:00 +0100 3459742 http://www.medworm.com/index.php?rid=3443177&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00134.x The extraordinary taxonomic and morphological diversity of orchids is accompanied by a remarkable range of pollinators and pollination systems. Sexually deceptive orchids are adapted to attract specific male insects that are fooled into attempting to mate with orchid flowers and inadvertently acting as pollinators. This review summarises current knowledge, explores new hypotheses in the literature, and introduces some new approaches to understanding sexual deception from the perspective of the duped pollinator. Four main topics are addressed: (1) global patterns in sexual deception, (2) pollinator identities, mating systems and behaviours, (3) pollinator perception of orchid deceptive signals, and (4) the evolutionary implications of pollinator responses to orchid deception, including pote... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3443177 Tue, 06 Apr 2010 23:00:00 +0100 3443177 http://www.medworm.com/index.php?rid=3432390&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00133.x We present the parasite-stress model of intrastate conflict, which unites previous work on the correlates of intrastate conflict by linking frequency of the outbreak of such conflict, including civil war, to the intensity of infectious disease across countries of the world. High intensity of infectious disease leads to the emergence of xenophobic and ethnocentric cultural norms. These cultures suffer greater poverty and deprivation due to the morbidity and mortality caused by disease, and as a result of decreased investment in public health and welfare. Resource competition among xenophobic and ethnocentric groups within a nation leads to increased frequency of civil war. We present support for the parasite-stress model with regression analyses. We find support for a direct effect of infec... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3432390 Thu, 01 Apr 2010 23:00:00 +0100 3432390 http://www.medworm.com/index.php?rid=3841867&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00135.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841867 Wed, 31 Mar 2010 23:00:00 +0100 3841867 http://www.medworm.com/index.php?rid=3353736&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00127.x It is now clear that mechanisms of sex determination are extraordinarily labile, with considerable variation across all taxonomic levels. This variation is often expressed through differences in the genetic system (XX-XY, XX-XO, haplodiploidy, and so on). Why there is so much variation in such a seemingly fundamental process has attracted much attention, with recent ideas concentrating on the possible role of genomic conflicts of interest. Here we consider the role of inter- and intra-genomic conflicts in one large insect taxon: the scale insects. Scale insects exhibit a dizzying array of genetic systems, and their biology promotes conflicts of interest over transmission and sex ratio between male- and female-expressed genes, parental- and offspring-expressed genes (both examples of intra-... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3353736 Thu, 11 Mar 2010 00:00:00 +0100 3353736 http://www.medworm.com/index.php?rid=3341951&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00129.x Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for plants. During recent years, knowledge about hydrochory and its ecological consequences has increased considerably and a substantial body of literature has been produced. Here, we review this literature and define the state of the art of the discipline. A substantial proportion of species growing in or near water have propagules (fruits, seeds or vegetative units) able to disperse by water, either floating, submerged in flowing water, or with the help of floating vessels. Hydrochory can enable plants to colonize sites out of reach with other dispersal vectors, but the timing of dispersal and mechanisms of establishment are important for successful establishment. At the p... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3341951 Mon, 08 Mar 2010 00:00:00 +0100 3341951 http://www.medworm.com/index.php?rid=3330767&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00131.x We propose that a basic biological imperative of all organisms is to maximise energy (E) intensity, defined as the average rate of energy use per unit area of the Earth's surface. The dominant organism in any given environment is predicted to be that exerting the greatest E intensity regardless of evolutionary origin. Our 'theory of biological E intensity' thus explains variation in life form in terms of adaptations as opposed to accidents of biological history. It defines the competitive criterion in all metabolic pathways and industrial processes as the average rate of kinetic energy use, excluding heating but including all directed biological kinesis at scales up to the whole organism. A suggested unit for E intensity is joules per square meter per year. Because catalysts are crucial to... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3330767 Thu, 04 Mar 2010 00:00:00 +0100 3330767 http://www.medworm.com/index.php?rid=3330770&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00128.x One often reads the following claims: (1) The modern conception of natural selection differs from Darwin's own conception only with respect to incidental features; (2) Natural selection is a very simple idea with enormous explanatory power. Both claims are problematic. R.A. Fisher famously argued that given a particulate view of inheritance, selection could proceed in a powerful manner even with frequent crossing, small fitness advantages and a low mutation rate. This is quite different from Darwin's view, which (roughly translated into a modern idiom) insists on infrequent crossing, large fitness advantages and a high mutation rate. The modern conception of natural selection is not the same as Darwin's, unless we describe natural selection in the most abstract manner. When so described, t... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3330770 Wed, 03 Mar 2010 00:00:00 +0100 3330770 http://www.medworm.com/index.php?rid=3330769&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00130.x Males of many species choose their mate according to the female's reproductive status, and there is now increasing evidence that male fitness can depend on this discrimination. However, females will also aim to regulate their mating activity so as to maximize their own fitness. As such, both sexes may attempt to dictate the frequency and timing of female mating, reflecting the potentially different costs of female signaling to both sexes. Here, I review evidence that chemical cues and signals are used widely by males to discriminate between mated and unmated females, and explore the mechanisms by which female odour changes post-mating. There is substantial empirical evidence that mated and unmated females differ in their chemical profile, and that this variation provides males with informa... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3330769 Wed, 03 Mar 2010 00:00:00 +0100 3330769 http://www.medworm.com/index.php?rid=3330768&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00132.x Adhesive systems are ubiquitous in benthic animals and play a key role in diverse functions such as locomotion, food capture, mating, burrow building, and defence. For benthic animals that release adhesives, surface and material properties and external morphology have received little attention compared to the biochemical content of the adhesives. We address temporary adhesion of benthic animals from the following three structural levels: (a) the biochemical content of the adhesive secretions, (b) the micro- and mesoscopic surface geometry and material properties of the adhesive organs, and (c) the macroscopic external morphology of the adhesive organs. We show that temporary adhesion of benthic animals is affected by three structural levels: the adhesive secretions provide binding to the s... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3330768 Wed, 03 Mar 2010 00:00:00 +0100 3330768 http://www.medworm.com/index.php?rid=3301519&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00125.x Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant[ndash]pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certai... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3301519 Wed, 24 Feb 2010 00:00:00 +0100 3301519 http://www.medworm.com/index.php?rid=3250595&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00126.x Comparative analyses aim to explain interspecific variation in phenotype among taxa. In this context, phylogenetic approaches are generally applied to control for similarity due to common descent, because such phylogenetic relationships can produce spurious similarity in phenotypes (known as phylogenetic inertia or bias). On the other hand, these analyses largely ignore potential biases due to within-species variation. Phylogenetic comparative studies inherently assume that species-specific means from intraspecific samples of modest sample size are biologically meaningful. However, within-species variation is often significant, because measurement errors, within- and between-individual variation, seasonal fluctuations, and differences among populations can all reduce the repeatability of a... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3250595 Mon, 08 Feb 2010 00:00:00 +0100 3250595 http://www.medworm.com/index.php?rid=3841868&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00126.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841868 Mon, 01 Feb 2010 00:00:00 +0100 3841868 http://www.medworm.com/index.php?rid=3219877&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00121.x Despite increasing interest in urban ecology the factors limiting the colonisation of towns and cities by species from rural areas are poorly understood. This is largely due to the lack of a detailed conceptual framework for this urbanisation process, and of sufficient case studies. Here, we develop such a framework. This draws upon a wide range of ecological and evolutionary theory and the increasing number of studies of how the markedly divergent conditions in urban and rural areas influence the traits of urban populations and the structure of urban assemblages. We illustrate the importance of this framework by compiling a detailed case study of spatial and temporal variation in the urbanisation of the blackbird Turdus merula. Our framework identifies three separate stages in the urbanis... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3219877 Fri, 29 Jan 2010 00:00:00 +0100 3219877 http://www.medworm.com/index.php?rid=3215815&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00120.x The focus of this review is the experimental techniques used to identify forms of social learning shown by humans and nonhuman animals. Specifically, the 'ghost display' and 'end-state' conditions, which have been used to tease apart imitative and emulative learning are evaluated. In a ghost display, the movements of an apparatus are demonstrated, often through the discrete use of fishing-line or hidden mechanisms, without a live model acting directly upon the apparatus so that the apparatus appears to be operated as if by a 'ghostly' agent. In an end-state condition, an observing individual is shown the initial state of the test apparatus, the apparatus is then manipulated out-of-sight and then represented to the individual in its final state. The aim of the ghost display condition is to ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3215815 Thu, 28 Jan 2010 00:00:00 +0100 3215815 http://www.medworm.com/index.php?rid=3207825&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00124.x The phylum Mollusca represents an enormous diversity of species with eight distinct classes. This review provides a taxonomic breakdown of the published research on marine molluscan natural products and the medicinal products currently derived from molluscs, in order to identify priority targets and strategies for future research. Some marine gastropods and bivalves have been of great interest to natural products chemists, yielding a diversity of chemical classes and several drug leads currently in clinical trials. Molluscs also feature prominently in a broad range of traditional natural medicines, although the active ingredients in the taxa involved are typically unknown. Overall secondary metabolites have only been investigated from a tiny proportion ( (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3207825 Tue, 26 Jan 2010 00:00:00 +0100 3207825 http://www.medworm.com/index.php?rid=3207827&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00122.x Endothermy has evolved at least twice, in the precursors to modern mammals and birds. The most widely accepted explanation for the evolution of endothermy has been selection for enhanced aerobic capacity. We review this hypothesis in the light of advances in our understanding of ATP generation by mitochondria and muscle performance. Together with the development of isotope-based techniques for the measurement of metabolic rate in free-ranging vertebrates these have confirmed the importance of aerobic scope in the evolution of endothermy: absolute aerobic scope, ATP generation by mitochondria and muscle power output are all strongly temperature-dependent, indicating that there would have been significant improvement in whole-organism locomotor ability with a warmer body. New data on mitocho... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3207827 Mon, 25 Jan 2010 00:00:00 +0100 3207827 http://www.medworm.com/index.php?rid=3207826&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00123.x Global change (climate change together with other worldwide anthropogenic processes such as increasing trade, air pollution and urbanization) will affect plant health at the genetic, individual, population and landscape level. Direct effects include ecosystem stress due to natural resources shortage or imbalance. Indirect effects include (i) an increased frequency of natural detrimental phenomena, (ii) an increased pressure due to already present pests and diseases, (iii) the introduction of new invasive species either as a result of an improved suitability of the climatic conditions or as a result of increased trade, and (iv) the human response to global change. In this review, we provide an overview of recent studies on terrestrial plant health in the presence of global change factors. W... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3207826 Mon, 25 Jan 2010 00:00:00 +0100 3207826 http://www.medworm.com/index.php?rid=3141918&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00119.x Dispersal has recently gained much attention because of its crucial role in the conservation and evolution of species facing major environmental changes such as habitat loss and fragmentation, climate change, and their interactions. Butterflies have long been recognized as ideal model systems for the study of dispersal and a huge amount of data on their ability to disperse has been collected under various conditions. However, no single 'best' method seems to exist leading to the co-occurrence of various approaches to study butterfly mobility, and therefore a high heterogeneity among data on dispersal across this group. Accordingly, we here reviewed the knowledge accumulated on dispersal and mobility in butterflies, to detect general patterns. This meta-analysis specifically addressed two q... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3141918 Tue, 05 Jan 2010 00:00:00 +0100 3141918 http://www.medworm.com/index.php?rid=3841870&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00123.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841870 Fri, 01 Jan 2010 00:00:00 +0100 3841870 http://www.medworm.com/index.php?rid=3841869&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2010.00120.x (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3841869 Fri, 01 Jan 2010 00:00:00 +0100 3841869 http://www.medworm.com/index.php?rid=3118381&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00117.x ABSTRACT A block to polyspermy is required for successful fertilisation and embryo survival in mammals. A higher incidence of polyspermy is observed during in vitro fertilisation (IVF) compared with the in vivo situation in several species. Two groups of mechanisms have traditionally been proposed as contributing to the block to polyspermy in mammals: oviduct-based mechanisms, avoiding a massive arrival of spermatozoa in the proximity of the oocyte, and egg-based mechanisms, including changes in the membrane and zona pellucida (ZP) in reaction to the fertilising sperm. Additionally, a mechanism has been described recently which involves modifications of the ZP in the oviduct before the oocyte interacts with spermatozoa, termed "pre-fertilisation zona pellucida hardening". This mechanism is... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3118381 Thu, 24 Dec 2009 00:00:00 +0100 3118381 http://www.medworm.com/index.php?rid=3108070&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00118.x Melatonin is a molecule present in a multitude of taxa and may be ubiquitous in organisms. It has been found in bacteria, unicellular eukaryotes, macroalgae, fungi, plants and animals. A primary biological function of melatonin in primitive unicellular organisms is in antioxidant defence to protect against toxic free radical damage. During evolution, melatonin has been adopted by multicellular organisms to perform many other biological functions. These functions likely include the chemical expression of darkness in vertebrates, environmental tolerance in fungi and plants, sexual signaling in birds and fish, seasonal reproductive regulation in photoperiodic mammals, and immunomodulation and anti-inflammatory activity in all vertebrates tested. Moreover, its waning production during aging ma... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3108070 Mon, 21 Dec 2009 00:00:00 +0100 3108070 http://www.medworm.com/index.php?rid=3108069&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00115.x Huddling can be defined as "an active and close aggregation of animals". It is a cooperative group behaviour, permitting individuals involved in social thermoregulation to minimize heat loss and thereby lower their energy expenditure, and possibly allowing them to reallocate the saved energy to other functions such as growth or reproduction. Huddling is especially important in the case of animals faced with high heat loss due to a high surface-to-volume ratio, poor insulation, or living in cold environments. Although numerous experimental studies have focused on the huddling behaviour of a wide range of species, to our knowledge, this is the first attempt to review the various implications of this widely used behavioural strategy. Huddling allows individuals to maximise energy savings by (... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3108069 Mon, 21 Dec 2009 00:00:00 +0100 3108069 http://www.medworm.com/index.php?rid=3088692&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00111.x Recent advances in phylogenetics and, in particular, molecular dating, indicate that transoceanic dispersal has played an important role in shaping plant and animal distributions, obscuring any effect of tectonic history. Taxonomic sampling in biogeographic studies is, however, systematically biased towards vertebrates and higher plants and the possibility remains that a much stronger signature of ancient vicariance might be evident among other organisms, particularly among basal land plants. Here, an explicit Bayesian model-based approach was used to investigate global-scale biogeographic patterns among liverwort genera and to determine whether the patterns identified are consistent with the expectations of vicariance or dispersal scenarios. The distribution of each genus was mapped onto ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3088692 Tue, 15 Dec 2009 00:00:00 +0100 3088692 http://www.medworm.com/index.php?rid=3088691&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00112.x This review describes recent developments in analysing the influence of radio-frequency electromagnetic fields (RF-EMFs ) on biological systems by monitoring the cellular stress response as well as overall gene expression. Recent data on the initiation and modulation of the classical cellular stress response by RF-EMFs, comprising expression of heat shock proteins and stimulation of stress-activated protein kinases, are summarised and evaluated. Since isothermic RF-EMF exposure is assumed rather than proven there are clear limitations in using the stress response to describe non-thermal effects of RF-EMFs. In particular, further experiments are needed to characterise better the threshold of the thermal heat shock response and the homogeneity of the cellular response in the whole sample for... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3088691 Tue, 15 Dec 2009 00:00:00 +0100 3088691 http://www.medworm.com/index.php?rid=3088690&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00113.x Resources are produced in pulses in many terrestrial environments, and have important effects on the population dynamics and assemblage structure of animals that consume them. Resource-pulsing is particularly dramatic in Australian desert environments owing to marked spatial and temporal variability in rainfall, and thus primary productivity. Here, we first review how Australia's desert mammals respond to fluctuations in resource production, and evaluate the merits of three currently accepted models (the ecological refuge, predator refuge and fire-mosaic models) as explanations of the observed dynamics. We then integrate elements of these models into a novel state-and-transition model and apply it to well-studied small mammal assemblages that inhabit the vast hummock grassland, or spinifex... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3088690 Tue, 15 Dec 2009 00:00:00 +0100 3088690 http://www.medworm.com/index.php?rid=3088689&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00114.x New data on spermiogenesis and the ultrastructure of spermatozoa of 'true' tapeworms (Eucestoda) are summarized. Since 2001, more than 50 species belonging to most orders of the Eucestoda have been studied or reinvestigated, particularly members of the Caryophyllidea, Spathebothriidea, Diphyllobothriidea, Bothriocephalidea, Trypanorhyncha, Tetraphyllidea, Proteocephalidea, and Cyclophyllidea. A new classification of spermatozoa of eucestodes into seven basic types is proposed and a key to their identification is given. For the first time, a phylogenetic tree inferred from spermatological characters is provided. New information obtained in the last decade has made it possible to fill numerous gaps in the character data matrix, enabling us to carry out a more reliable analysis of the evoluti... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3088689 Tue, 15 Dec 2009 00:00:00 +0100 3088689 http://www.medworm.com/index.php?rid=3088688&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00116.x The recent publication of hypotheses explaining the homeotic control of floral organ identity together with the availability of increasingly comprehensive and well-resolved molecular phylogenies presents an ideal opportunity for reassessing current knowledge of floral diversity and evolution in the Annonaceae. This review summarizes currently available information on selected aspects of floral structure and function, including: changes in the number of perianth whorls and the number of perianth parts per whorl; the evolution of sympetaly; the diversity and evolution of pollination chambers (with a novel classification of seven main structural forms of floral chamber based on the different arrangement, size and shape of petals); the evolution of perianth glands; floral unisexuality and hypo... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3088688 Tue, 15 Dec 2009 00:00:00 +0100 3088688 http://www.medworm.com/index.php?rid=3078618&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00097.x Body size is a key feature of organisms and varies continuously because of the effects of natural selection on the size-dependency of resource acquisition and mortality rates. This review provides a critical and synthetic overview of body size variation in insects from a predominantly macroecological (large-scale temporal and spatial) perspective. Because of the importance of understanding the proximate determinants of adult size, it commences with a brief summary of the physiological mechanisms underlying adult body size and its variation, based mostly on findings for the model species Drosophila melanogaster and Manduca sexta. Variation in nutrition and temperature have variable effects on critical weight, the interval to cessation of growth (or terminal growth period) and growth rates, ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3078618 Fri, 11 Dec 2009 00:00:00 +0100 3078618 http://www.medworm.com/index.php?rid=3074835&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00110.x Eukaryotic flagella and cilia have a remarkably uniform internal 'engine' known as the '9+2' axoneme. With few exceptions, the function of cilia and flagella is to beat rhythmically and set up relative motion between themselves and the liquid that surrounds them. The molecular basis of axonemal movement is understood in considerable detail, with the exception of the mechanism that provides its rhythmical or oscillatory quality. Some kind of repetitive 'switching' event is assumed to occur; there are several proposals regarding the nature of the 'switch' and how it might operate. Herein I first summarise all the factors known to influence the rate of the oscillation (the beating frequency). Many of these factors exert their effect through modulating the mean sliding velocity between the nin... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3074835 Thu, 10 Dec 2009 00:00:00 +0100 3074835 http://www.medworm.com/index.php?rid=3074837&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00107.x Previous attempts to resolve plesiosaurian phylogeny are reviewed and a new phylogenetic data set of 66 taxa (67% of ingroup taxa examined directly) and 178 characters (eight new) is presented. We recover two key novel results: a monophyletic Plesiosauridae comprising Plesiosaurus dolichodeirus, Hydrorion brachypterygius, Microcleidus homalospondylus, Occitanosaurus tournemirensis and Seeleyosaurus guilelmiimperatoris; and five plesiosaurian taxa recovered outside the split between Plesiosauroidea and Pliosauroidea. These taxa are Attenborosaurus conybeari, 'Plesiosaurus'macrocephalus and a clade comprising Archaeonectrus rostratus, Macroplata tenuiceps and BMNH 49202. Based on this result, a new name, Neoplesiosauria, is erected for the clade comprising Plesiosauroidea and Pliosauroidea. ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3074837 Wed, 09 Dec 2009 00:00:00 +0100 3074837 http://www.medworm.com/index.php?rid=3074836&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00109.x Coevolutionary studies on plants and plant-feeding insects have significantly improved our understanding of the role of niche shifts in the generation of new species. Evolving plant lineages essentially constitute moving islands and archipelagoes in resource space, and host shifts by insects are usually preceded by colonizations of novel resources. Critical to hypotheses concerning ecological speciation is what happens immediately before and after colonization attempts: if an available plant is too similar to the current host(s), it simply will be incorporated into the existing diet, but if it is too different, it will not be colonized in the first place. It thus seems that the probability of speciation is maximized when alternative hosts are at an 'intermediate' distance in resource space... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3074836 Wed, 09 Dec 2009 00:00:00 +0100 3074836 http://www.medworm.com/index.php?rid=3070539&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00108.x Measuring pollinator performance has become increasingly important with emerging needs for risk assessment in conservation and sustainable agriculture that require multi-year and multi-site comparisons across studies. However, comparing pollinator performance across studies is difficult because of the diversity of concepts and disparate methods in use. Our review of the literature shows many unresolved ambiguities. Two different assessment concepts predominate: the first estimates stigmatic pollen deposition and the underlying pollinator behaviour parameters, while the second estimates the pollinator's contribution to plant reproductive success, for example in terms of seed set. Both concepts include a number of parameters combined in diverse ways and named under a diversity of synonyms an... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3070539 Wed, 09 Dec 2009 00:00:00 +0100 3070539 http://www.medworm.com/index.php?rid=3033288&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00092.x Lampreys are a group of aquatic chordates whose relationships to hagfishes and jawed vertebrates are still debated. Lamprey embryology is of interest to evolutionary biologists because it may shed light on vertebrate origins. For this and other reasons, lamprey embryology has been extensively researched by biologists from a range of disciplines. However, many of the key studies of lamprey comparative embryology are relatively inaccessible to the modern scientist. Therefore, in view of the current resurgence of interest in lamprey evolution and development, we present here a review of lamprey developmental anatomy. We identify several features of early organogenesis, including the origin of the nephric duct, that need to be re-examined with modern techniques. The homologies of several struc... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3033288 Fri, 27 Nov 2009 00:00:00 +0100 3033288 http://www.medworm.com/index.php?rid=3026095&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00099.x Over the last three decades, the fossil record of spiders has increased from being previously biased towards Tertiary ambers and a few dubious earlier records, to one which reveals a much greater diversity in the Mesozoic, with many of the modern families present in that era, and with clearer evidence of the evolutionary history of the group. We here record the history of palaeoarachnology and the major breakthroughs which form the basis of studies on fossil spiders. Understanding the preservation and taphonomic history of spider fossils is crucial to interpretation of fossil spider morphology. We also review the more recent descriptions of fossil spiders and the effect these discoveries have had on the phylogenetic tree of spiders. We discuss some features of the evolutionary history of s... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026095 Wed, 25 Nov 2009 00:00:00 +0100 3026095 http://www.medworm.com/index.php?rid=3026102&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00100.x Precise and deep comprehension of plant responses to herbivorous arthropods requires detailed knowledge of how a plant "notices" the attack. Herbivore attack is not restricted to plant wounding by feeding, but instead different phases of attack that elicit a plant response need to be distinguished: touch, oviposition and feeding. Touch, secretions released with eggs and regurgitate delivered during feeding may act in concert as elicitors of plant defence. Here, we discuss the current knowledge of what a plant "notices" during the different phases of herbivore attack and how it responds at the molecular, physiological and ecological level. Understanding the mechanisms of plant responses to the different phases of herbivore attack will be a key challenge in unravelling the complex communicat... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026102 Tue, 24 Nov 2009 00:00:00 +0100 3026102 http://www.medworm.com/index.php?rid=3026101&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00102.x It is argued that conscious emotional feelings can not be adequately explained by just particular circuits or coherent activations within the brain, as is conventionally believed; nor by activations representing environmental stimuli going to the brain. According to the model suggested herein, the limbic system responds to sensory and other inputs according to how closely they are associated with built-in rewards or punishments. It does this by (a) activating the autonomic nervous system so that it prepares the body to acquire a reward or avoid a punishment, and (b) also activating the prefrontal cortex (PFC). The PFC activations are temporally correlated with the autonomic activations and the feedback to them, so that they become identified with the autonomic attempts to acquire (a reward... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026101 Tue, 24 Nov 2009 00:00:00 +0100 3026101 http://www.medworm.com/index.php?rid=3026100&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00103.x Recent studies of animal personality have focused on its proximate causation and its ecological and evolutionary significance, but have mostly ignored questions about its development, although an understanding of the latter is highly relevant to these other questions. One possible reason for this neglect is confusion about many of the concepts and terms that are necessary to study the development of animal personality. Here, we provide a framework for studying personality development that focuses on the properties of animal personality, and considers how and why these properties may change over time. We specifically focus on three dimensions of personality: (1) contextual generality at a given age or time, (2) temporal consistency in behavioural traits and in relationships between traits, ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026100 Tue, 24 Nov 2009 00:00:00 +0100 3026100 http://www.medworm.com/index.php?rid=3026099&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00104.x Over the last two decades increasing evidence for an acute sensitivity to human gestures and attentional states in domestic dogs has led to a burgeoning of research into the social cognition of this highly familiar yet previously under-studied animal. Dogs (Canis lupus familiaris) have been shown to be more successful than their closest relative (and wild progenitor) the wolf, and than man's closest relative, the chimpanzee, on tests of sensitivity to human social cues, such as following points to a container holding hidden food. The "Domestication Hypothesis" asserts that during domestication dogs evolved an inherent sensitivity to human gestures that their non-domesticated counterparts do not share. According to this view, sensitivity to human cues is present in dogs at an early age and ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026099 Tue, 24 Nov 2009 00:00:00 +0100 3026099 http://www.medworm.com/index.php?rid=3026098&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00105.x This review article is an attempt to trace the evolution of mast cells (MCs). These immune cells have been identified in all vertebrate classes as single-lobed cells containing variable amounts of membrane-bound secretory granules which store a large series of mediators, namely histamine, proteases, cytokines and growth factors. Other MC features, at least in mammals, are the c-kit receptor for the stem cell factor and the high-affinity receptor, Fc[epsilon]RI, for immunoglobulin E (IgE). The c-kit receptor also has been identified in fish MCs. The Fc[epsilon]RI receptor seems to be a more recent acquisition in MC phylogenesis given that IgE originated in mammalian species. Tryptase and histamine have also been recognized in MCs of teleost fish. Thus, a cell population with the overall cha... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026098 Tue, 24 Nov 2009 00:00:00 +0100 3026098 http://www.medworm.com/index.php?rid=3026097&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00106.x Conservation objectives for non-breeding coastal birds (shorebirds and wildfowl) are determined from their population size at coastal sites. To advise coastal managers, models must predict quantitatively the effects of environmental change on population size or the demographic rates (mortality and reproduction) that determine it. As habitat association models and depletion models are not able to do this, we developed an approach that has produced such predictions thereby enabling policy makers to make evidence-based decisions. Our conceptual framework is individual-based ecology, in which populations are viewed as having properties (e.g. size) that arise from the traits (e.g. behaviour, physiology) and interactions of their constituent individuals. The link between individuals and populati... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026097 Tue, 24 Nov 2009 00:00:00 +0100 3026097 http://www.medworm.com/index.php?rid=3026096&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00098.x Housed worldwide, mostly in museums and herbaria, is a vast collection of biological specimens developed over centuries. These biological collections, and associated taxonomic and systematic research, have received considerable long-term public support. The work remaining in systematics has been expanding as the estimated total number of species of organisms on Earth has risen over recent decades, as have estimated numbers of undescribed species. Despite this increasing task, support for taxonomic and systematic research, and biological collections upon which such research is based, has declined over the last 30-40 years, while other areas of biological research have grown considerably, especially those that focus on environmental issues. Reflecting increases in research that deals with ec... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3026096 Tue, 24 Nov 2009 00:00:00 +0100 3026096 http://www.medworm.com/index.php?rid=3022444&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00096.x Understanding how an organism develops into a fully functioning adult from a mass of undifferentiated cells may reveal different strategies that allow the organism to survive under limiting conditions. Here, we review an analytical model for characterizing quantitative trait loci (QTLs) that underlie variation in growth trajectories and developmental timing. This model, called functional mapping, incorporates fundamental principles behind biological processes or networks that are bridged with mathematical functions into a statistical mapping framework. Functional mapping estimates parameters that determine the shape and function of a particular biological process, thus providing a flexible platform to test biologically meaningful hypotheses regarding the complex relationships between gene ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3022444 Tue, 24 Nov 2009 00:00:00 +0100 3022444 http://www.medworm.com/index.php?rid=3022445&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00093.x A major conservation concern is whether population size and other ecological variables change linearly with habitat loss, or whether they suddenly decline more rapidly below a "critical threshold" level of habitat. The most commonly discussed explanation for critical threshold responses to habitat loss focus on habitat configuration. As habitat loss progresses, the remaining habitat is increasingly fragmented or the fragments are increasingly isolated, which may compound the effects of habitat loss. In this review we also explore other possible explanations for apparently nonlinear relationships between habitat loss and ecological responses, including Allee effects and time lags, and point out that some ecological variables will inherently respond nonlinearly to habitat loss even in the ab... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3022445 Mon, 23 Nov 2009 00:00:00 +0100 3022445 http://www.medworm.com/index.php?rid=3003196&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00101.x Consistent individual behavioural tendencies, termed "personalities", have been identified in a wide range of animals. Functional explanations for personality have been proposed, but as yet, very little consideration has been given to a possible role for sexual selection in maintaining differences in personality and its stability within individuals. We provide an overview of the available literature on the role of personality traits in intrasexual competition and mate choice in both human and non-human animals and integrate this into a framework for considering how sexual selection can generate and maintain personality. For this, we consider the evolution and maintenance of both main aspects of animal personality: inter-individual variation and intra-individual consistency. (Source: Biolog... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=3003196 Wed, 18 Nov 2009 00:00:00 +0100 3003196 http://www.medworm.com/index.php?rid=2969887&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00094.x The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly mo... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2969887 Sat, 07 Nov 2009 00:00:00 +0100 2969887 http://www.medworm.com/index.php?rid=2969888&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00095.x The scaling of metabolic rate with body mass has long been a controversial topic. Some workers have claimed that the slope of log-log metabolic scaling relationships typically obeys a universal 3/4-power law resulting from the geometry of resource-transport networks. Others have attempted to explain the broad diversity of metabolic scaling relationships. Although several potentially useful models have been proposed, at present none successfully predicts the entire range of scaling relationships seen among both physiological states and taxonomic groups of animals and plants. Here I argue that our understanding may be aided by three shifts in focus: from explaining average tendencies to explaining variation between extreme boundary limits, from explaining the slope and elevation (metabolic l... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2969888 Fri, 06 Nov 2009 00:00:00 +0100 2969888 http://www.medworm.com/index.php?rid=2919517&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00091.x We used the supertree approach of matrix representation with parsimony to reconstruct to date the most exhaustive (genus-level) phylogeny of Cyprinidae. The supertree of Cyprinidae, representing 397 taxa (237 nominal genera) and 990 pseudocharacters, was well resolved (96%) through extended consensus majority rule, although 36 nodes (9.4%) were unsupported. The proportion of shared taxa among source trees was very low after calculation of the taxonomic coverage index (TCI = 0.059), which is proposed here as a more accurate alternative to the usual ratios calculated from the number of pseudo-characters or source trees per taxon. We define a new index for the calculation of partitioned qualitative clade support, the partitioned rQS (prQS), which offers a straightforward visualization of the ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2919517 Wed, 21 Oct 2009 23:00:00 +0100 2919517 http://www.medworm.com/index.php?rid=2761280&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00090.x We describe: (1) how conformational changes in the Ca2+ sensor calmodulin result in the exposure of binding pockets for the target proteins (CaMKs and calcineurin). (2) How Calmodulin consequently activates either the Ca2+/calmodulin-dependent kinases pathways (via CaMKs) or calmodulin-dependent serine/threonine phosphatases (via calcineurin). (3) How calmodulin kinases alter transcription in the nucleus through the phosphorylation, deactivation and translocation of histone deacetylase 4 (HDAC4) from the nucleus to the cytoplasm. (4) How calcineurin transmits signals to the nucleus through the dephosphorylation and translocation of NFAT from the cytoplasm to the nucleus. (Source: Biological Reviews) Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2761280 Wed, 02 Sep 2009 23:00:00 +0100 2761280 http://www.medworm.com/index.php?rid=2761281&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00088.x Alternation of generations underpins all plant life histories and is held to possess important adaptive features. A wide range of data have accumulated over the past century which suggest that alternation from sporophyte to gametophyte in angiosperms includes a significant phase of 'informational reprogramming', leaving the founder cells of the gametophyte developmentally uncommitted. This review attempts to bring together results from these historic studies with more recent data on molecular and epigenetic events which accompany alternation, gametophyte development and gametogenesis in angiosperms. It is striking that most members of the other principal group of multicellular eukaryotes [ndash] the animals - have a completely different a life history: animals generate their gametes direct... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2761281 Tue, 01 Sep 2009 23:00:00 +0100 2761281 http://www.medworm.com/index.php?rid=2681392&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00087.x Parasitism is a common cause of host mortality, but little is known about the ecological factors affecting parasite virulence (the rate of mortality among infected hosts). We reviewed 117 field estimates of parasite-induced nestling mortality in birds, showing that there was significant consistency in mortality among host and parasite taxa. Virulence increased towards the tropics in analyses of both species-specific data and phylogenetic analyses. We found evidence of greater parasite prevalence being associated with reduced virulence. Furthermore, bird species breeding in open nest sites suffered from greater parasite-induced mortality than hole-nesting species. By contrast, parasite specialization and generation time of parasites relative to that of hosts explained little variation in vi... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2681392 Fri, 07 Aug 2009 23:00:00 +0100 2681392 http://www.medworm.com/index.php?rid=2681393&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00086.x We review digestion and osmoregulation in the avian gut, with an emphasis on the ways these different functions might interact to support or constrain each other and the ways they support the functioning of the whole animal in its natural environment. Differences between birds and other vertebrates are highlighted because these differences may make birds excellent models for study and may suggest interesting directions for future research. At a given body size birds, compared with mammals, tend to eat more food but have less small intestine and retain food in their gastrointestinal tract (GIT) for shorter periods of time, despite generally higher mass-specific energy demands. On most foods, however, they are not less efficient at digestion, which begs the question how they compensate. Inte... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2681393 Thu, 06 Aug 2009 23:00:00 +0100 2681393 http://www.medworm.com/index.php?rid=2670384&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00089.x The extent to which interspecific interference competition has contributed to character evolution is one of the most neglected problems in evolutionary biology. When formerly allopatric species come into secondary contact, aggressive interactions between the species can cause selection on traits that affect interspecific encounter rates (e.g. habitat preferences, activity schedules), competitor recognition (e.g. colouration, song), and fighting ability (e.g. weaponry, body size). We define agonistic character displacement (ACD) as the process of phenotypic evolution in a population caused by interference competition with one or more sympatric species and which results in shifts in traits that affect the rate, intensity or outcome of interspecific aggression. After clarifying the relationsh... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2670384 Tue, 04 Aug 2009 23:00:00 +0100 2670384 http://www.medworm.com/index.php?rid=2439824&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00080.x Conventional approaches to population biology emphasise the roles of climatic conditions, nutrient flow and predation as constraints on population dynamics. We argue here that this focus has obscured the role of time as a crucial constraint on species' abilities to survive in some habitats. Time constraints may be particularly intrusive both for species that live in intensely bonded groups (where the need to devote time to social interaction may ultimately limit the size of group that a species can maintain in a particular habitat) and for taxa that face constraints on the length of the active day. We use a linear programming approach that allows us to specify both how time allocations to different activities are influenced by local environmental and climatic variables and how these in tur... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2439824 Thu, 28 May 2009 04:00:00 +0100 2439824 http://www.medworm.com/index.php?rid=2439823&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00081.x Increased sediment loading comprises one of the most important and pervasive anthropogenic impacts on aquatic ecosystems globally. In spite of this, little is known of the overall effects of increased sediment loads on lakes. By modifying both bottom-up and top-down ecological processes and restructuring energy flow pathways, increased sediment loads not only alter biotic assemblage structure and ecological functioning significantly, but frequently result in reduced biological diversity and productivity. Although lake food-webs can be subsidised to some extent by the adsorption of organic carbon to fine sediments, trophic structure and the composition of biotic assemblages remain likely to be modified considerably. The mineralogy and particle size of sediments and the availability of nutri... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2439823 Thu, 28 May 2009 04:00:00 +0100 2439823 http://www.medworm.com/index.php?rid=2439825&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00078.x Litterbags have been utilized in soil ecology for about 50 years. They are useful because they confine organic material and thus enable the study of decomposition dynamics (mass loss and/or nutrient loss through time, colonization by soil biota) in situ, i.e. under field conditions. Researchers can easily restrict or permit access to certain size classes of soil fauna to determine their contribution to litter mass loss by choosing adequate mesh size or applying specific biocides. In particular, the mesofauna has received much attention since it comprises two very abundant and diverse microarthropod groups, the Collembola (springtails) and Acari (mites). We comprehensively searched the literature from the mid-1960s to the end of 2005 for reports on litterbag experiments investigating the ro... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2439825 Wed, 27 May 2009 04:00:00 +0100 2439825 http://www.medworm.com/index.php?rid=2386514&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2008.00076.x The importance of wild birds as potential vectors of disease has received recent renewed empirical interest, especially regarding human health. Understanding the spread of bacterial pathogens in wild birds may serve as a useful model for examining the spread of other disease organisms, both amongst birds, and from birds to other taxa. Information regarding the normal gastrointestinal bacterial flora is limited for the majority of wild bird species, with the few well-studied examples concentrating on bacteria that are zoonotic and/or relate to avian species of commercial interest. However, most studies are limited by small sample sizes, the frequent absence of longitudinal data, and the constraints of using selective techniques to isolate specific pathogens. The pathogenic genera found in t... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2386514 Mon, 04 May 2009 04:00:00 +0100 2386514 http://www.medworm.com/index.php?rid=2340005&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2009.00077.x Resorption and remodelling of skeletal tissues is required for development and growth, mechanical adaptation, repair, and mineral homeostasis of the vertebrate skeleton. Here we review for the first time the current knowledge about resorption and remodelling of the skeleton in teleost fish, the largest and most diverse group of extant vertebrates. Teleost species are increasingly used in aquaculture and as models in biomedical skeletal research. Thus, detailed knowledge is required to establish the differences and similarities between mammalian and teleost skeletal remodelling, and between distantly related species such as zebrafish (Danio rerio) and medaka (Oryzias latipes). The cellular mechanisms of differentiation and activation of osteoclasts and the functions of teleost skeletal remo... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2340005 Thu, 16 Apr 2009 04:00:00 +0100 2340005 http://www.medworm.com/index.php?rid=2340004&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2008.00075.x Animal signals may result from construction behaviour and can provide receivers with essential information in various contexts. Here we explore the potential benefits of extended phenotypes with a signalling function as compared to bodily ornaments and behavioural displays. Their independence of the body, their physical persistence and the morphological and cognitive conditions required for their construction allow unique communication possibilities. We classify various levels of information transfer by extended phenotype signals and explore the differences between secreted signals and signals resulting from collection and construction, which usually involve higher behavioural complexity. We examine evolutionary pathways of extended phenotypes with a signalling function with help of a comp... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2340004 Thu, 16 Apr 2009 04:00:00 +0100 2340004 http://www.medworm.com/index.php?rid=2323930&cid=s_37715_62_f&fid=37715&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-185X.2008.00074.x Many of the diverse animals that consume floral rewards act as efficient pollinators; however, others 'steal' rewards without 'paying' for them by pollinating. In contrast to the extensive studies of the ecological and evolutionary consequences of nectar theft, pollen theft and its implications remain largely neglected, even though it affects plant reproduction more directly. Here we review existing studies of pollen theft and find that: (1) most pollen thieves pollinate other plant species, suggesting that theft generally arises from a mismatch between the flower and thief that precludes pollen deposition, (2) bees are the most commonly documented pollen thieves, and (3) the floral traits that typically facilitate pollen theft involve either spatial or temporal separation of sex function ... Biological Reviews journals http://www.medworm.com/rss/comments.php?id=2323930 Sat, 11 Apr 2009 04:00:00 +0100 2323930