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 'Ethology' source. Mon, 06 Feb 2012 23:35:09 +0100 http://www.medworm.com/index.php?rid=5664799&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2012.02027.x AbstractAccording to life‐history theory, the duration of extended parental feeding is determined by the costs and benefits of maximising reproductive success. Therefore, the length of regular parental provisioning should be correlated with the time required for juveniles to acquire the skills that they need to be independent. The relatively few cases of extremely prolonged parental feeding in both land and sea birds appear to be consistent with this prediction because they are associated with learning‐intensive foraging techniques. New Caledonian crows have the most intricate tool manufacture techniques amongst non‐human animals and juveniles take over 1 yr to reach adult‐like proficiency in their tool skills. We investigated the prediction that this species also should have pro... Ethology journals http://www.medworm.com/rss/comments.php?id=5664799 Wed, 01 Feb 2012 05:00:00 +0100 5664799 http://www.medworm.com/index.php?rid=5644661&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2012.02023.x AbstractComplex courtship signals can be dissected into distinct components that can either function independently or via interactions with one another. Male Rabidosa rabida wolf spiders use courtship displays that couple a seismic signal with the waving of an ornamented foreleg. While previous studies suggest that female R. rabida exhibit mate choice and that both the seismic and visual modalities are important in mating interactions, it remains unclear how variation in each component influences female mating decisions. To investigate this, we ran two separate experiments in which we manipulated (1) male diets, to induce variation in the seismic courtship signal, and (2) male foreleg color, to artificially induce variation in visual foreleg ornamentation. To determine the influence of va... Ethology journals http://www.medworm.com/rss/comments.php?id=5644661 Wed, 01 Feb 2012 00:51:19 +0100 5644661 http://www.medworm.com/index.php?rid=5644662&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02019.x AbstractSexual selection theory suggests males in good condition should be more successful than males in poor condition when competing with rivals for territories and mates. Understanding how condition influences the interplay between aggression, mate attraction, and courtship displays could help explain why variation is maintained in traits that confer fitness. Using laboratory‐reared Jamaican field crickets, Gryllus assimilis, we found that fine‐scale temporal components of mate attraction signals were positively correlated with body condition (residual body mass) and body size; signaling effort was positively correlated with both body condition and fine‐scale temporal signaling components; aggression was positively correlated with signaling effort; number of eggs laid was positive... Ethology journals http://www.medworm.com/rss/comments.php?id=5644662 Mon, 30 Jan 2012 05:00:00 +0100 5644662 http://www.medworm.com/index.php?rid=5625443&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02018.x AbstractIn territorial species, it is sometimes less costly to help a neighbour fight off an intruder than to re‐establish territory boundaries with a new, potentially stronger neighbour. In fiddler crabs, a male resident will only help his neighbour if he is larger than the intruder who, in turn, is larger than the challenged neighbour. Does this influence with whom a territory‐seeking male decides to fight? I show that territory‐seeking males appear to choose opponents based partly on the size of the resident’s nearest neighbour. By avoiding challenging resident males with larger neighbours, territory‐seeking males can reduce the likelihood of initiating a fight with a resident who might gain help from his neighbour that decreases the likelihood that the intruder will win the f... Ethology journals http://www.medworm.com/rss/comments.php?id=5625443 Wed, 25 Jan 2012 06:04:38 +0100 5625443 http://www.medworm.com/index.php?rid=5617772&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02016.x AbstractAlthough bats are highly social mammals, the mechanisms influencing the establishment of social structures are far from being fully understood. So far, no study has addressed the effects of spatial proximity between newborns such as that occurring in nursery clusters on the development of preferential associations among individuals. We tested such effects on captive pups of Kuhl’s pipistrelle Pipistrellus kuhlii. During the first 6 wks, we kept them in separate rearing groups. Once able to fly, bats were allowed to freely interact in a common flight room, where those reared in the same groups showed higher rates of amicable interactions (proximity during roosting, allogrooming, huddling) but no effect on aggressive behaviour. Sex also influenced such frequencies, females being ... Ethology journals http://www.medworm.com/rss/comments.php?id=5617772 Sun, 22 Jan 2012 04:21:00 +0100 5617772 http://www.medworm.com/index.php?rid=5594285&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02017.x This study demonstrates that consistent individual differences and decision‐making strategies may be resistant to recent aggressive experiences, even over a period of days. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5594285 Mon, 16 Jan 2012 06:32:28 +0100 5594285 http://www.medworm.com/index.php?rid=5594286&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02013.x AbstractVocal and facial masculinity are cues to underlying testosterone in men and influence women’s mate preferences. Consistent with the proposal that facial and vocal masculinity signal common information about men, prior work has revealed correlated female preferences for male facial and vocal masculinity. Previous studies have assessed women’s preferences for male facial and vocal masculinity by presenting faces and voices independently and using static face stimuli. By contrast, here we presented women with short video clips in which male faces and voices were simultaneously manipulated in masculinity. We found that women who preferred masculine faces also preferred masculine voices. Furthermore, women whose faces were rated as relatively more attractive preferred both facial an... Ethology journals http://www.medworm.com/rss/comments.php?id=5594286 Wed, 11 Jan 2012 05:00:00 +0100 5594286 http://www.medworm.com/index.php?rid=5577230&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02014.x AbstractAs a part of our research on the evolution of social learning in insects, we examined socially influenced behaviour and social learning in desert locust (Schistocerca gregaria) nymphs and adults. In the nymphs, the only positive effect we documented was an increased tendency to feed while in the company of another locust than alone. The adults, on the other hand, showed significant preference for joining others (local enhancement) in both the contexts of feeding and egg laying. Neither nymphs nor adults, however, showed social learning. Our preliminary analyses pointed to locusts as a likely insect that might possess social learning. Our research, when taken together with research on phase‐shifts and swarm/marching behaviour of gregarious locusts, suggests that the behavioural dy... Ethology journals http://www.medworm.com/rss/comments.php?id=5577230 Tue, 10 Jan 2012 11:17:06 +0100 5577230 http://www.medworm.com/index.php?rid=5569961&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01999.x AbstractBird song is a widely used model in the study of sexual selection. Variation in the expression of sexually selected traits is thought to reflect variation in male genetic and/or phenotypic quality. Vocal amplitude is a song parameter that has received little attention in the context of sexual selection, but there is some evidence that the intensity of bird song affects female preferences. Here, we tested whether the amplitude of broadcast song plays a role in male–male competition. We used song playback with varying song amplitude (within the natural amplitude range of the species) and a dummy bird taxidermy to simulate territorial intrusions in the great tit, Parus major, during the fertile period of the female and measured the response of the local male. The results show that p... Ethology journals http://www.medworm.com/rss/comments.php?id=5569961 Sat, 07 Jan 2012 11:47:08 +0100 5569961 http://www.medworm.com/index.php?rid=5569960&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02012.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5569960 Sat, 07 Jan 2012 11:46:51 +0100 5569960 http://www.medworm.com/index.php?rid=5569958&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02011.x AbstractIndividual variation in vocalizations is a common feature of many forms of long‐distance communication in vertebrates. The extent to which individual variation occurs in non‐vocal, long‐distance acoustic communication has not, however, been tested. Here, we examine the spectral and temporal characteristics of a non‐vocal acoustic signal, the wing‐beating drumming display of the male Ruffed Grouse (Bonasa umbellus, L.), and test whether its structure varies more among individuals than within them. Drumming displays were recorded over two field seasons, and we measured several temporal and spectral features of these recordings. Each drumming display consists of 39–50 pulses produced over a period of 9–10 s with most of the energy concentrated at frequencies below 100�... Ethology journals http://www.medworm.com/rss/comments.php?id=5569958 Sat, 07 Jan 2012 11:46:36 +0100 5569958 http://www.medworm.com/index.php?rid=5569959&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02015.x AbstractAmong polygynous species, males often compete for the possession of mating sites to increase their reproductive success. Weaker individuals frequently adopt alternative non‐territorial mate‐locating tactics, but the adoption of alternative territorial tactics may also occur. Although alternative tactics with territory defence are less common in arthropods, factors that drive its adoption may provide information to understand the organization of different territorial mating systems in the group. Here we investigate the adoption of resource‐based territoriality as an alternative to a non‐resource‐based one by males of the butterfly Paryphthimoides phronius. Male P. phronius commonly defend sunny clearings lacking feeding resources in the forest edge (non‐resource‐based... Ethology journals http://www.medworm.com/rss/comments.php?id=5569959 Thu, 05 Jan 2012 05:00:00 +0100 5569959 http://www.medworm.com/index.php?rid=5534533&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02009.x AbstractIt has been established that various species exhibit personality, defined as intra‐individual consistency and inter‐individual variation in behavioural phenotypes. For example, certain individuals may demonstrate consistently greater behavioural reactions and elevated stress responses. We conducted playback experiments and hormonal analyses on male chimpanzees (Pan troglodytes) in captivity to investigate the patterns and proximate mediators of individual variations in behavioural reactions. We found intra‐individual consistency and inter‐individual variation in behavioural reactions (intensive vigilance towards the direction of speakers) to vocalisations by unfamiliar chimpanzees. This behavioural reaction was positively correlated with changes in salivary cortisol concent... Ethology journals http://www.medworm.com/rss/comments.php?id=5534533 Fri, 23 Dec 2011 17:20:59 +0100 5534533 http://www.medworm.com/index.php?rid=5534536&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02005.x AbstractBi‐directional sex change has recently been reported in a range of reef fishes, including haremic species that were earlier thought to be protogynous (female to male). However, the occurrence of this phenomenon and the social conditions driving the reversion of males to females (reversed sex change) have been poorly documented under natural conditions. Reversed sex change is predicted to occur in low‐density populations where facultative monogamy is common. However, few studies have evaluated this over a long period in such populations. We documented the occurrence of bi‐directional sex change during a 3‐yr demographic survey of a population characterised by small harem sizes in haremic hawkfish Cirrhitichthys falco. New males were derived following a change in sex of funct... Ethology journals http://www.medworm.com/rss/comments.php?id=5534536 Thu, 22 Dec 2011 05:00:00 +0100 5534536 http://www.medworm.com/index.php?rid=5534535&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02006.x AbstractIn species where advancing sire age is associated with decreased progeny fitness, female resistance to mating with old partners can be expected to evolve. In polyandrous species, such resistance may be contingent on female mating experience: virgins should be relatively indiscriminate to ensure egg fertility, whereas non‐virgins can be expected to base their re‐mating decisions on the age of their previous versus potential new partners, and ‘trade‐up’ if previously mated with old males. Here, we tested these predictions using a promiscuous and relatively long‐living bulb mite (Rhizoglyphus robini), in which old sire age is associated with decreased fecundity of daughters. In a fully factorial design, we applied two male treatments, young and old, and three female treatm... Ethology journals http://www.medworm.com/rss/comments.php?id=5534535 Thu, 22 Dec 2011 05:00:00 +0100 5534535 http://www.medworm.com/index.php?rid=5534534&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02010.x AbstractResearch shows that hormonal changes in women across the menstrual cycle affect vocal production. Most work has documented shifts at high fertility times (i.e., ovulation) or during premenstruation. However, hormonal changes at menstruation also affect female physiology and behavior and could affect vocal production. The present studies investigated perceptual differences in voices recorded during menstruation compared with recordings taken at other times of the menstrual cycle. Results show that male raters could reliably identify voices recorded during menstruation with or without the presence of a voice recorded closest to ovulation. In addition, voices recorded at menstruation were identified as being the most unattractive. These findings indicate that voice recordings taken at... Ethology journals http://www.medworm.com/rss/comments.php?id=5534534 Thu, 22 Dec 2011 05:00:00 +0100 5534534 http://www.medworm.com/index.php?rid=5513199&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01998.x AbstractOne major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment declined significantly in low‐density populations with male turnover, while growth of high‐de... Ethology journals http://www.medworm.com/rss/comments.php?id=5513199 Sat, 17 Dec 2011 16:52:18 +0100 5513199 http://www.medworm.com/index.php?rid=5513207&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01996.x In this study, we evaluated the importance of shelter residency effects relative to size differences between rusty crayfish (Orconectes rusticus) as potential competitors for access to shelter. The intensity of any residency effects was manipulated by altering the number of shelters in the arena. Our results suggest that any residency effect is very weak in this system, and if present, may often be masked by the strong and pervasive influence on contest outcome of the relative body sizes of the contestants. We also found that both shelter number and crayfish size asymmetries had strong, independent effects on levels of aggression. Dominance, but not residency status, was a factor in shelter use. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5513207 Thu, 15 Dec 2011 05:00:00 +0100 5513207 http://www.medworm.com/index.php?rid=5513206&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01997.x AbstractOlfactory predators and scavengers rely on odors to locate food, and they forage primarily at night. We hypothesized that weather (e.g. wind speed, humidity, and temperature), vegetation, and landscape features affect the dissipation of odors in the atmosphere and, thus, impact the foraging efficiency of olfactory predators. We tested this hypothesis by assessing what conditions were correlated with the persistence of bait along the dike surrounding Willard Bay Reservoir, Utah. We distributed 124 chicken eggs and 199 dead European starlings (Sturnus vulgaris) as bait over 21 separate occasions spanning from May 21, 2009, to August 18, 2009. We used timers to record the time of consumption and cameras to identify which species ate the bait. Sixty‐six eggs and 87 dead European star... Ethology journals http://www.medworm.com/rss/comments.php?id=5513206 Thu, 15 Dec 2011 05:00:00 +0100 5513206 http://www.medworm.com/index.php?rid=5513205&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02004.x AbstractReciprocal altruism is considered to be particularly stable when occurring in small networks. Using a stable isotope approach, we tested in colonies of vampire bats (Desmodus rotundus) whether food sharing occurs among few or many females; vampires are known to regurgitate recently ingested blood for starving conspecifics. Accordingly, the isotopic signatures of vampires depend not only on individual prey choice but also on the extent of food sharing among isotopically contrasting conspecifics. By measuring the stable carbon isotope ratio in tissues with varying isotopic retention in individual vampires (blood: approx. 2 wk; wing membrane tissue: approx. 2 mo; fur: >6 mo), we estimated the variation in the percentages of carbon derived from pasture (via blood from cattle a... Ethology journals http://www.medworm.com/rss/comments.php?id=5513205 Thu, 15 Dec 2011 05:00:00 +0100 5513205 http://www.medworm.com/index.php?rid=5513204&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01991.x AbstractA positive relationship across species between the extent to which females mate with more than one male and relative testes mass has been demonstrated in a wide range of vertebrate taxa and certain insects. At least two hypotheses, which are not necessarily mutually exclusive, could account for this pattern: (1) the numerical sperm competition hypothesis, which assumes that larger testes enable the male to transfer more sperm to each female, giving the male an advantage in sperm competition and (2) the male mating rate hypothesis, which proposes that larger testes allow the male to produce a greater number of (potentially smaller) ejaculates to engage in frequent copulations with different females. Of these hypotheses, the former has won broad acceptance, while the latter has tende... Ethology journals http://www.medworm.com/rss/comments.php?id=5513204 Thu, 15 Dec 2011 05:00:00 +0100 5513204 http://www.medworm.com/index.php?rid=5513203&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01992.x AbstractIt has been suggested that African wild dogs Lycaon pictus need exceptionally large home ranges (and hence occur at such low densities) because they are limited by competition with larger sympatric carnivores, namely lions Panthera leo and spotted hyenas Crocuta crocuta. To investigate this relationship at a proximate level and explore which factors mediate it, we conducted audio playback experiments examining how wild dogs responded to the simulated proximity of either lions or hyenas. The principle finding was that wild dogs consistently moved directly away from lion roars, but when played hyena whoops either stood their ground or, later, moved off in a random direction. These results suggest that lions represent an immediate high‐level threat to wild dogs that is invariably be... Ethology journals http://www.medworm.com/rss/comments.php?id=5513203 Thu, 15 Dec 2011 05:00:00 +0100 5513203 http://www.medworm.com/index.php?rid=5513202&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01993.x In this study, we tested whether the characteristics (duration, speed and frequency) of an aggressive display, the push‐up body rock, exhibited by the Jacky dragon (Amphibolurus muricatus) have likely evolved for optimal signal efficiency, as it is able to draw attention to the signaller. We performed two video playback experiments using high‐resolution 3D animations testing the effect of variation in push‐up body rock structure. In experiment 1, we manipulated push‐up body rock display structure. We gradually increased the number of push‐ups exhibited by a digitally animated Jacky dragon increasing the overall display duration. In experiment 2, we developed four stimuli based on population‐typical push‐up body rock display for duration (short and long), and frequency of push... Ethology journals http://www.medworm.com/rss/comments.php?id=5513202 Thu, 15 Dec 2011 05:00:00 +0100 5513202 http://www.medworm.com/index.php?rid=5513201&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01994.x This study underlines that a higher competitor density does not necessarily lead to a lower intake rate, irrespective of dominance status. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5513201 Thu, 15 Dec 2011 05:00:00 +0100 5513201 http://www.medworm.com/index.php?rid=5513200&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01995.x AbstractWe studied movements and conflicts within a small flock of free‐living black‐tailed godwits foraging on benthic invertebrates in a brackish lagoon. To interpret our results in the framework of foraging theory, we studied the influence of individual feeding rate on the decisions to move and to attack flock companions. Birds changed their position within the flock more often when their intake rate was low and sometimes attacked conspecifics to supplant them from their feeding place. Aggressors significantly avoided front attacks and were almost always successful. They attacked individuals having higher feeding rates than themselves and their own feeding rate significantly increased after the attack, although victims were not chased off to particularly poor sites. Our results sugg... Ethology journals http://www.medworm.com/rss/comments.php?id=5513200 Thu, 15 Dec 2011 05:00:00 +0100 5513200 http://www.medworm.com/index.php?rid=5484183&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02007.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5484183 Thu, 08 Dec 2011 17:37:48 +0100 5484183 http://www.medworm.com/index.php?rid=5484179&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02003.x AbstractNest defence is a common form of parental care employed by birds to improve the survival of their offspring. Theory predicts that parents should adjust their nest defence according to the value of the brood at stake, defending more intensively broods with high survival and reproductive prospects. We evaluated the influence of offspring number, offspring age, laying date and parent sex on nest‐defence intensity (NDI) of the Imperial Shag Phalacrocorax atriceps, a sexually dimorphic seabird with seasonal decline in offspring survival and very limited renesting potential. We also evaluated whether NDI was correlated within pairs and whether NDI of both members of the pair was correlated with incubation and breeding success. To elicit defensive behaviour, we simulated predation attem... Ethology journals http://www.medworm.com/rss/comments.php?id=5484179 Thu, 08 Dec 2011 17:37:41 +0100 5484179 http://www.medworm.com/index.php?rid=5484182&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02000.x AbstractIt is widely admitted that sexual selection is the responsible force behind genital traits. However, the particular mechanisms of genital evolution are still debated. Recently, studies of genital static allometry in insects have been used to elucidate such mechanisms. Insect genital traits are often reported to show negative allometry (i.e., a slope < 1), which has generated a number of ideas on how genital traits are selected. However, many studies that have inferred selection mechanisms have omitted consideration of the function of genital traits, used unreliable indicators of body size, and only rarely included female genitalia in their analysis. We investigated whether negative allometry operates for genitalia in two damselfly species (Protoneura cara and Ischnura dentic... Ethology journals http://www.medworm.com/rss/comments.php?id=5484182 Thu, 08 Dec 2011 05:00:00 +0100 5484182 http://www.medworm.com/index.php?rid=5484181&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02001.x AbstractThe ability to unlearn a previously established association is an important component of behavioural flexibility and may vary according to species ecology. Previously, two closely related sympatric Darwin’s finches were found to differ in their learning abilities. Small tree finches (Camarhynchus parvulus) outperformed woodpecker finches (Cactospiza pallida) in reversal learning but performed worse in an operant task. We attributed this difference to the habit of woodpecker finches to engage in long bouts of energetic pecking during extractive foraging. Persistently repeating one action without reward could favour performance in operant tasks but also limit behavioural flexibility. Here, we tested whether perseverance is the reason for woodpecker finches’ depressed reversal lea... Ethology journals http://www.medworm.com/rss/comments.php?id=5484181 Thu, 08 Dec 2011 05:00:00 +0100 5484181 http://www.medworm.com/index.php?rid=5484180&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.02002.x AbstractIndividuals may obtain valuable information about the presence of predators by listening to heterospecific alarm signals. Most playback studies have demonstrated that similarly sized and taxonomically related species may respond to the calls of each other, but less work has been carried out to define these factors influence responsiveness to alarm signals. In theory, individuals should respond to calls from any species that provide information about the presence of important predators, regardless of body size or taxonomic relationship. However, size is often associated with vulnerability. Coyotes (Canis latrans) in the Rocky Mountains prey upon both mule deer (Odocoileus hemionus) and yellow‐bellied marmots (Marmota flaviventris), which differ considerably in size, alarm vocaliza... Ethology journals http://www.medworm.com/rss/comments.php?id=5484180 Thu, 08 Dec 2011 05:00:00 +0100 5484180 http://www.medworm.com/index.php?rid=5448140&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01989.x AbstractNumerous recent studies have revealed a variety of behavioral adaptations of rodents for maximizing returns from cached seeds. Herein we report on a novel behavior by the Siberian chipmunk (Tamias sibiricus) in northeastern China, by which they consistently remove the pericarp (shell) of Quercus mongolica acorns before dispersing and caching these nuts. We investigated the effects of pericarp removal on acorn germination, tannin concentrations, cache pilferage, and insect damage, to determine if and how pericarp removal facilitates cache management by Siberian chipmunks and whether or not such behavior influences seed fates. Chipmunks cached acorns only after the pericarps were removed. Chipmunks preferred pericarp‐removed acorns over intact acorns when removing them from seed st... Ethology journals http://www.medworm.com/rss/comments.php?id=5448140 Sat, 26 Nov 2011 17:55:09 +0100 5448140 http://www.medworm.com/index.php?rid=5448142&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01990.x AbstractThe concept of partner compatibility in monogamous animals implies that individuals may reproduce better when paired to a partner with similar traits than to a higher quality, but dissimilar individual. We investigated whether partner similarities in traits that are linked in a behavioural syndrome influence reproductive performance in a wild population of Steller’s jays. In some years, pairs more similar in explorative tendencies and in willingness to take risks initiated nests earlier and were more likely to fledge offspring than dissimilar pairs. Benefits of behavioural similarity differed among breeding seasons, being most pronounced in a year with late breeding onset after a severe winter. Pairing patterns for behavioural traits also varied among years and traits, and assort... Ethology journals http://www.medworm.com/rss/comments.php?id=5448142 Thu, 24 Nov 2011 05:00:00 +0100 5448142 http://www.medworm.com/index.php?rid=5448141&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01988.x AbstractThe question of why animals participate in duets is an intriguing one, as many such displays appear to be more costly to produce than individual signals. Mated pairs of yellow‐naped amazons, Amazona auropalliata, give duets on their nesting territories. We investigated the function of those duets with a playback experiment. We tested two hypotheses for the function of those duets: the joint territory defense hypothesis and the mate‐guarding hypothesis, by presenting territorial pairs with three types of playback treatments: duets, male solos, and female solos. The joint territory defense hypothesis suggests that individuals engage in duets because they appear more threatening than solos and are thus more effective for the establishment, maintenance and/or defense of territories... Ethology journals http://www.medworm.com/rss/comments.php?id=5448141 Thu, 24 Nov 2011 05:00:00 +0100 5448141 http://www.medworm.com/index.php?rid=5438009&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01987.x AbstractThere should be intense selection for predation avoidance mechanisms when prey live in close proximity to their predators. Prey individuals that can learn to associate habitat features with high levels of predation risk should experience increased survival if they subsequently avoid those habitats. We tested whether or not habitat learning occurred in a benthic stream community consisting of adult Oklahoma salamander (Eurycea tynerensis) prey and a syntopic predatory fish, the banded sculpin (Cottus carolinae). We exposed individual salamanders to chemical stimuli from sculpin, non‐predatory tadpoles, or a blank control in training tanks containing either rocks or grass. Two days later, the salamanders were tested in tanks that offered a choice of rocks or grass. Salamanders show... Ethology journals http://www.medworm.com/rss/comments.php?id=5438009 Wed, 23 Nov 2011 16:37:44 +0100 5438009 http://www.medworm.com/index.php?rid=5438010&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01986.x AbstractPlumage colour can be used as an honest signal to convey health and status, which has traditionally been examined in the sexual selection context of choosy females and elaborate males. We use a model avian system to study the role of plumage coloration in a social context such as inter‐ and intrasexual competition over food resources. The diamond firetail (Stagonopleura guttata) is an endemic Australian finch: females have more white flank spots than males, and white spot number was correlated with cell‐mediated immune response in females. We use two experimental designs to test the role of white flank spots for feeding dominance and dominance discrimination in a group‐living bird. The results from two‐choice trials and from single‐arena trials showed that female ornament... Ethology journals http://www.medworm.com/rss/comments.php?id=5438010 Sun, 20 Nov 2011 05:00:00 +0100 5438010 http://www.medworm.com/index.php?rid=5418845&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01983.x AbstractIn a system with multiple predators, the threat‐sensitive predator avoidance hypothesis predicts that prey respond differently to predators relative to the risks each poses (e.g., degree of dietary specialization). Aquatic animals often rely heavily on detecting predators via chemical cues (kairomones) and respond with a suite of behaviors including detection and avoidance. However, little is known about how animals respond to kairomones of specialist versus generalist predators. In laboratory experiments, we compared behavioral responses of a poorly studied aquatic salamander, the greater siren (Siren lacertina), to cues from specialist and generalist predator snakes to evaluate threat‐sensitive responses. Sirens exhibited a novel behavior (gill‐flushing) most often in the p... Ethology journals http://www.medworm.com/rss/comments.php?id=5418845 Fri, 18 Nov 2011 07:10:35 +0100 5418845 http://www.medworm.com/index.php?rid=5397771&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01985.x AbstractSexual selection has often been dichotomized into intersexual and intrasexual components of selection, favoring ornaments and weapons, respectively. Here, we show that a weapon used in male–male combat is sometimes also used in a functionally similar manner for grasping females during mating. The hind legs of adult males of some species of Pristoceuthophilus camel crickets have strongly bent tibia and stout femora with two large conspicuous spines. Here, we show that (1) leg armature is positively allometric, (2) males use these leg modifications when fighting other males, (3) males sometimes use the same leg modifications in the same functional manner for grabbing and holding females for mating, (4) virgin females show more interest in males than do non‐virgin females, and (5)... Ethology journals http://www.medworm.com/rss/comments.php?id=5397771 Fri, 11 Nov 2011 17:49:03 +0100 5397771 http://www.medworm.com/index.php?rid=5397772&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01982.x This study demonstrates that willow tits use long‐distance calls to attract conspecific flockmates to foraging patches, and these calls can also facilitate the formation of mixed‐species flocks on patches. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5397772 Fri, 04 Nov 2011 04:00:00 +0100 5397772 http://www.medworm.com/index.php?rid=5344308&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01981.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5344308 Mon, 24 Oct 2011 14:26:29 +0100 5344308 http://www.medworm.com/index.php?rid=5344307&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01975.x In this study, we investigated the acoustic structure of copulation calls in bonobos (Pan paniscus), a great ape known for its heightened socio‐sexuality. Throughout their cycles, females engage in sexual relations with both males and other females and produce copulation calls with both partners. We found that calls produced during sexual interactions with male and female partners could not be reliably distinguished in terms of their acoustic structure, despite major differences in mating behaviour and social context. Call structure was equally unaffected by the size of a female’s sexual swelling and by the rank of her mating partner. Rank of the partner did affect call delivery although only with male, but not female partners. The only strong effect on call structure was because of ca... Ethology journals http://www.medworm.com/rss/comments.php?id=5344307 Mon, 24 Oct 2011 14:26:25 +0100 5344307 http://www.medworm.com/index.php?rid=5344306&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01973.x AbstractAnimals are communicating by sound face interference from biotic and abiotic sources. Contrasting strategies have been reported in different taxa in the presence of prolonged noises, but in particular, interactions among acoustically active species have been studied to a very limited extent. In addition, reactions of a single species to interferences having contrasting structural patterns have not been explored systematically. The vocal responses of 16 male frogs Batrachyla antartandica from the temperate austral forest in Chile were tested with conspecific calls and with the calls of two sympatric species: B. taeniata and B. leptopus, broadcast at amplitudes of 73, 79, 85, 91, and 97 dB peak sound pressure level (SPL). Also, the vocal activity of the subjects during exposure t... Ethology journals http://www.medworm.com/rss/comments.php?id=5344306 Mon, 24 Oct 2011 14:26:24 +0100 5344306 http://www.medworm.com/index.php?rid=5344305&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01964.x AbstractIn many hierarchical animal societies, dominant individuals control group membership owing to their power to evict subordinates. In such groups, the presence of subordinates, and therefore group stability, is continually dependent on subordinates being tolerated by dominants. The dominant decision to tolerate or evict is, in turn, dependent on the costs and benefits to dominants of subordinate presence. We investigated the effect of subordinate presence on dominants in the female dominance hierarchy of the dwarf angelfish Centropyge bicolor, using both observations of natural groups and experimental removals of subordinates. We found that the presence of subordinates had no effect on dominant access to resources, as measured by dominant foraging rates and home range areas, nor on d... Ethology journals http://www.medworm.com/rss/comments.php?id=5344305 Mon, 24 Oct 2011 14:26:16 +0100 5344305 http://www.medworm.com/index.php?rid=5344304&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01984.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5344304 Mon, 24 Oct 2011 14:26:05 +0100 5344304 http://www.medworm.com/index.php?rid=5344301&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01980.x In this study, we examined the factors that underlie individual variation in the tendency to engage in non‐conceptive mating and determine whether it impacts male–male competition for females. We found that docile females, being less resistant to mating in general, are more likely to accept male courtship and non‐conceptive copulation as juveniles. Personality type influenced the exhibition of non‐conceptive sexual behavior in males as well. High body condition males of the aggressive phenotype were more likely to engage in non‐conceptive sexual behavior than males with lower body condition. Body condition did not influence docile males’ propensity to engage in non‐conceptive sexual behavior, but female size did. Docile males engaged in more non‐conceptive sexual displays w... Ethology journals http://www.medworm.com/rss/comments.php?id=5344301 Mon, 24 Oct 2011 14:25:57 +0100 5344301 http://www.medworm.com/index.php?rid=5344303&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01978.x AbstractAnti‐predator behavior can affect prey growth, reproduction, survival, and generate emergent effects in food webs. Small mammals often lower the cost of predation by altering their behavior in response to shrubs, but the importance of other microhabitat features, such as downed woody debris, for anti‐predator behavior is unknown. We used giving‐up densities to quantify the degree to which downed woody debris alters perceived predation risk by small mammals in southeastern pine forests. We placed 14 foraging trays next to large downed woody debris, shrubs, and in open areas for 12 consecutive nights. Moon illumination, a common indicator of predation risk, led to a similar reduction in small mammal foraging in all three microhabitats (open, downed woody debris, and shrub). Sma... Ethology journals http://www.medworm.com/rss/comments.php?id=5344303 Sun, 23 Oct 2011 04:00:00 +0100 5344303 http://www.medworm.com/index.php?rid=5344302&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01979.x AbstractBird song has the potential to convey a variety of information about the singer, including the singer’s current motivational state. A recent review by Searcy & Beecher (2009) (Anim. Behav. 78, 2009; 1281) emphasized how little is currently known about whether song functions as an aggressive signal in territorial interactions. A recent observational study of song length variation in the Puget Sound white‐crowned sparrow reported that males shorten the terminal trill in their single song type while singing close by another male, and shorten the trill even further immediately before chasing the opponent. Here, we report the results of two song playback experiments designed to test whether males distinguish the differences in song length that occur in agonistic and non‐agonis... Ethology journals http://www.medworm.com/rss/comments.php?id=5344302 Sun, 23 Oct 2011 04:00:00 +0100 5344302 http://www.medworm.com/index.php?rid=5331731&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01974.x AbstractCollective detection of predators is one of the main advantages of living in groups in prey species. However, the mechanisms linking individual and collective vigilance remain largely unknown. Here, we investigated individual and collective vigilance in a natural population of greater kudu (Tragelaphus strepsiceros), a gregarious ruminant living under high predation risk. Controlling for environmental, individual and group factors, we show that the proportion of time during which at least one individual was vigilant increased with group size, whereas individual investment in vigilance decreased. We also show that individuals tended to synchronize both vigilance and feeding activities. More generally, and whatever the considered group size, we demonstrate how the independent scannin... Ethology journals http://www.medworm.com/rss/comments.php?id=5331731 Thu, 20 Oct 2011 12:42:09 +0100 5331731 http://www.medworm.com/index.php?rid=5331739&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01972.x AbstractNests of social insects are an attractive resource in terms of nutrition and shelter and therefore targeted by a variety of pathogens and parasites that harness the resources of a host colony in their own reproductive interests. Colonies of the ants Formica fusca and F. lemani serve as hosts for mound‐building Formica species, the queens of which use host colonies during colony founding. Here, we investigate whether workers of the host species can mitigate the costs imposed on them by invading parasite queens by recognizing and selectively removing eggs laid by these queens. We used behavioural assays, allowing host workers to choose between con‐colonial eggs and eggs laid by the parasite species F. truncorum. We show that workers of both host species discriminate between the... Ethology journals http://www.medworm.com/rss/comments.php?id=5331739 Tue, 18 Oct 2011 04:00:00 +0100 5331739 http://www.medworm.com/index.php?rid=5331738&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01976.x In this study, we tested the current view of territory shape by mapping multiple central‐place territories for 50 young‐of‐the‐year Atlantic salmon. Multiple central‐place areas were more elongated (eccentricity: median = 1.301, range = 1.043–2.784) than the foraging patterns around each central place (eccentricity: median = 1.135, range = 1.014–1.385). In addition, multiple central‐place areas were elongated along the stream length (33 of 50 fish), whereas the foraging areas around each station tended to be elongated along the stream width (32 of 50 fish). These findings may be explained by the way that stream salmonids interact with drifting prey. At each central place, a wider foraging area should provide an increased access to prey drifting downstream. S... Ethology journals http://www.medworm.com/rss/comments.php?id=5331738 Tue, 18 Oct 2011 04:00:00 +0100 5331738 http://www.medworm.com/index.php?rid=5331737&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01963.x We examined the antipredator behavior of a large dragonfly nymph, Anax junius, from a historically fishless pond where these animals have traditionally been classified as top predators. These dragonfly nymphs displayed a series of distinct aggressive antipredator behaviors when grasped that involved stabbing with lateral and posterior spines and seizing with labial hooks. Larger (older) nymphs displayed these aggressive behaviors significantly more than smaller (younger) animals in simulated predation trials. During encounters with live larval salamander predators (Ambystoma tigrinum), all large nymphs, but only 12.5% of small nymphs successfully escaped predation attempts by the amphibians through the use of antipredator behavior. Large nymphs were also significantly more active than smal... Ethology journals http://www.medworm.com/rss/comments.php?id=5331737 Tue, 18 Oct 2011 04:00:00 +0100 5331737 http://www.medworm.com/index.php?rid=5331736&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01965.x We examined the importance of female choice by testing whether females prefer the larger of two simultaneously presented males as mating partners. Further, we examined the influence of male–male competition by comparing the fighting behaviour between large and small males when alone or when together with a female, and we determined the outcome of fights. We found that females approach and choose large males as mating partners, despite the risk of male cannibalism. Additionally, males intensively compete for females, and large males clearly win against smaller ones. Hence sexual selection seems to be important for the evolution of the peculiar sexual size dimorphism of water spiders, as large size is beneficial for males in both the intra‐ and intersexual context. Previous studies have ... Ethology journals http://www.medworm.com/rss/comments.php?id=5331736 Tue, 18 Oct 2011 04:00:00 +0100 5331736 http://www.medworm.com/index.php?rid=5331735&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01967.x AbstractSome animals minimize the high costs of aggressive conflict by using conventional signals of agonistic ability to assess rivals prior to interacting. Conventional signals are more controversial than other signals of agonistic ability because they lack an inherent physical or physiological link with their bearer’s agonistic ability. Here, we test whether the variable brown facial stripes in Polistes exclamans paper wasps function as a conventional signal. Polistes exclamans were given the option of challenging or avoiding a rival with an experimentally altered facial pattern. Our results show that rival assessment is based on the facial patterns of rivals, as well as an individual’s own size, facial patterns, and nesting strategy. Individuals with larger body size and larger bro... Ethology journals http://www.medworm.com/rss/comments.php?id=5331735 Tue, 18 Oct 2011 04:00:00 +0100 5331735 http://www.medworm.com/index.php?rid=5331734&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01968.x AbstractMany aspects of the social behaviour of birds are mediated by vocal displays, and variation in song output or song structure conveys different information to receivers. After nest construction begins, when vermilion flycatcher (Pyrocephalus rubinus) females are potentially fertile, males increase their song rate during the dawn chorus. A previous study failed to give evidence that males discriminate among song rates. However, males sing in sequences of songs (song bouts), and an increase in song rate may be achieved by increasing the number of bouts, the number of songs in each bout (bout size) or both. Studying a vermilion flycatcher population in Mexico City, we evaluated whether dawn song rate is related to song bout size or to number of bouts. Bout size correlated with song rat... Ethology journals http://www.medworm.com/rss/comments.php?id=5331734 Tue, 18 Oct 2011 04:00:00 +0100 5331734 http://www.medworm.com/index.php?rid=5331733&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01971.x In this study, we investigated mating strategies in the Mediterranean black widow spider Latrodectus tredecimguttatus and tested the adaptive value of female attacks against male monopolization efforts. In a double mating experiment, we manipulated the number of insertions (=copulations) for first and second males to assess female behaviour and male embolus sclerite placement success. Our results indicate that first males′ embolus sclerites inside the females′ sperm stores physically block sclerites of subsequent males. While female attacks did not affect the deposition of potential mating plugs, they significantly reduced copulation duration. Irrespective of female aggression, male sclerite placement failure occurred frequently, but large males were more successful than smaller compet... Ethology journals http://www.medworm.com/rss/comments.php?id=5331733 Tue, 18 Oct 2011 04:00:00 +0100 5331733 http://www.medworm.com/index.php?rid=5322058&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01970.x AbstractMale field crickets frequently engage in agonistic contests to establish dominance in social interactions and gain access to mate attraction territories. Crickets (Orthoptera: Gryllidae) are often used as a model taxon to study aggression, but limited documentation of aggression in some cricket species hinders our understanding of its evolutionary costs and benefits. Our study investigated cricket aggression at two scales: the within‐species scale for two cricket species, Gryllus assimilis and G. veletis, whose aggression had not been adequately documented and the among‐species scale to detect evolutionary patterns in species’ levels of aggression. In both G. veletis and G. assimilis, winners spent more time being aggressive than losers, but they were not larger or heavier... Ethology journals http://www.medworm.com/rss/comments.php?id=5322058 Sun, 16 Oct 2011 19:20:42 +0100 5322058 http://www.medworm.com/index.php?rid=5311842&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01977.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5311842 Thu, 13 Oct 2011 18:09:47 +0100 5311842 http://www.medworm.com/index.php?rid=5322060&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01969.x AbstractMany hosts of avian brood parasites such as the common cuckoo (Cuculus canorus) show refined egg discrimination behaviour. Egg recognition in most open‐nesting hosts seems to be based entirely on differences in colour. However, hole‐ and dome‐nesting hosts may rely largely on luminance contrasts. Here, we studied egg rejection behaviour in nightingales (Luscinia megarhynchos), an open‐nesting species that nests in deeply shadowed positions and lays very specific dark olive‐green eggs. Although being theoretically suitable as hosts of the cuckoo, nightingales are very rarely parasitized and no cuckoo egg morph mimicking nightingale eggs is known. Thus, we predicted high rejection rate of foreign eggs, but because of the dim nesting environments, luminance contrasts would b... Ethology journals http://www.medworm.com/rss/comments.php?id=5322060 Thu, 13 Oct 2011 04:00:00 +0100 5322060 http://www.medworm.com/index.php?rid=5282334&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01956.x AbstractIn group‐living species, the development of agonistic interactions among conspecifics may be affected by socio‐ecological factors, such as size and composition of social group, and availability of nests and food. We analysed the importance of size and composition of social groups on agonistic interactions among males in the Southern mountain cavy (Microcavia australis). We made behavioural observations in four social groups of different size and composition. We recorded two types of agonistic interactions: agonistic displays and direct agonistic behaviours; both types increased in the breeding season. A social group composed of a high number of males was associated with high frequency of agonistic displays. Direct agonistic behaviours were also influenced by the interaction of ... Ethology journals http://www.medworm.com/rss/comments.php?id=5282334 Mon, 03 Oct 2011 04:00:00 +0100 5282334 http://www.medworm.com/index.php?rid=5282333&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01957.x AbstractThe use of acoustic signals by males during courtship and mating is well known. Nevertheless, their association with female unwillingness to mate is much less studied. In spiders, stridulation during sexual interactions is relatively common in some groups, but mainly restricted to males. In the pholcid spider Holocnemus pluchei, both sexes have stridulatory organs. The aims of the present work were (1) to establish whether female stridulation occurs during intra‐ and inter‐sexual interactions, (2) to determine whether female reproductive status affects the likelihood that she will stridulate and (3) to determine whether female stridulation is influenced by male sexual behaviour. We found that female stridulation usually occurs both during intrasexual interactions and, most freq... Ethology journals http://www.medworm.com/rss/comments.php?id=5282333 Mon, 03 Oct 2011 04:00:00 +0100 5282333 http://www.medworm.com/index.php?rid=5282332&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01961.x AbstractLarge male fiddler crabs sometimes help smaller neighbours to defend their territories against intruders. These coalitions occur when the helper is likely to defeat the intruder (helper larger than intruder) and the neighbour is likely to lose his territory without help (intruder larger than neighbour). Previous studies of coalitions have excluded males with regenerated claws. Such claws are weaker weapons that make the bearer competitively inferior. Here, we show that male Uca annulipes with regenerated claws are as likely as males with original claws to help their neighbours in territory defence, even though, as weaker males they potentially pay greater costs, being more likely to lose their undefended burrow. We suggest that males with regenerated claws gain greater benefits fro... Ethology journals http://www.medworm.com/rss/comments.php?id=5282332 Mon, 03 Oct 2011 04:00:00 +0100 5282332 http://www.medworm.com/index.php?rid=5302193&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01966.x AbstractIntraspecific group hunting has received considerable attention by researchers interested in cooperative behaviour and animal cognition. Differences between species in the complexity of the hunting with respect to communication, coordination and food sharing have typically been interpreted as a reflection of differences in cognitive abilities. Here we describe for the first time collaborative hunting where individuals play different roles in a fish species, the yellow saddle goatfish Parupeneus cyclostomus. Adults in our study area may live either solitarily or in relatively stable groups formed of similar sized and most likely unrelated individuals. The solitary life style was associated with searching for hidden immobile prey on sandy areas while group living was associated with ... Ethology journals http://www.medworm.com/rss/comments.php?id=5302193 Sat, 01 Oct 2011 04:00:00 +0100 5302193 http://www.medworm.com/index.php?rid=5282331&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01962.x AbstractPrior fighting experience of opponents can influence the outcome of conflicts. After a victory, animals are more likely to win subsequent contests, whereas after a defeat animals are more likely to lose, regardless of the identity of opponents. The underlying mechanisms and the adaptive significance of these winner and loser effects are as yet unknown. Here, we tested experimentally whether agonistic behavior of male wild‐type Norway rats is influenced by social experience, and we investigated whether this might reduce fighting costs (duration of contest, risk of injury) in subsequent encounters. Rats were randomly assigned to receive either a losing or a winning experience and subsequently tested with unfamiliar, naïve opponents. We found that most rats with a winning experienc... Ethology journals http://www.medworm.com/rss/comments.php?id=5282331 Sat, 01 Oct 2011 04:00:00 +0100 5282331 http://www.medworm.com/index.php?rid=5269977&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01959.x In conclusion, cleaners are able to track the ‘when’ and ‘what’ (or possibly ‘who’) within a biologically meaningful time period. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5269977 Sat, 01 Oct 2011 03:32:52 +0100 5269977 http://www.medworm.com/index.php?rid=5257872&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01960.x AbstractSpatial and temporal variation in ecological parameters selects for plastic responses to prevailing conditions. Males of web spiders have been shown to adjust developmental decisions to cues that relate to the degree of competition from other males. Here, we explore experimentally whether males of the spider Nephila senegalensis base behavioural decisions in the context of mate choice and sperm allocation to the presence of cues of a rival and to their own competitive dominance. Large and small males were offered a simultaneous choice between two penultimate instar females that varied in quality and in whether they were previously visited by a rival male. Large and small males avoided webs visited by a previous male, and this preference overrode differences in female quality. In a ... Ethology journals http://www.medworm.com/rss/comments.php?id=5257872 Tue, 27 Sep 2011 11:20:19 +0100 5257872 http://www.medworm.com/index.php?rid=5257873&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01958.x AbstractOlder males often have a mating advantage, either resulting from the fact that they live longer or resulting from the fact that they both live longer and signal this to females. Male field crickets signal acoustically to attract potential mates. Some field cricket mating signals provide cues about male age while others do not. We explored whether male Jamaican field crickets, Gryllus assimilis, mating signals change with age. Our results show that older males produce chirps with longer pulses, more pulses, at higher pulse and chirp rates, and their chirps are both longer and louder than those produced by younger males. Our findings suggest that Jamaican field cricket mating signals provide cues about male age, explaining between 10% and 54% of the variation in signaling traits. Fem... Ethology journals http://www.medworm.com/rss/comments.php?id=5257873 Sun, 25 Sep 2011 04:00:00 +0100 5257873 http://www.medworm.com/index.php?rid=5234514&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01955.x AbstractNycthemeral rhythm is an important biological trait that allows animals to escape predation and competition and, conversely, to coincide with mutualists. Although laboratory studies have shown that the rhythm depends on both endogenous factors and cyclic environmental cues, the latter is often poorly understood, particularly in the wild. Because insects are mostly ectothermal organisms, their activity rhythm is often thought to depend directly on ground temperature. In Mediterranean habitats, Cataglyphis ants are well known for their unusual thermoresistance, allowing them to forage in summer at the central hours of the day when the ground reaches temperatures that are lethal to their competitors. However, we show that the rhythm of Cataglyphis floricola in south‐western Spain is... Ethology journals http://www.medworm.com/rss/comments.php?id=5234514 Tue, 20 Sep 2011 07:11:22 +0100 5234514 http://www.medworm.com/index.php?rid=5234515&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01952.x AbstractIn Trinidad, guppies (Poecilia reticulata) in high‐predation localities show more cohesive shoaling behaviour than those living with less dangerous predators in low‐predation sites. We evaluated the relative contributions of population origin (i.e. genetic and/or maternal effects) and social environment on the expression of shoaling by assessing the behaviour of juveniles reared in a range of social conditions. Focal individuals, offspring of guppies from populations from high‐ or low‐predation localities, were reared in a multifactorial experiment; we created four different social conditions by manipulating the source and demography of the conspecific residents with whom focal individuals interacted. We found that high‐predation fish displayed a stronger propensity to sh... Ethology journals http://www.medworm.com/rss/comments.php?id=5234515 Mon, 19 Sep 2011 04:00:00 +0100 5234515 http://www.medworm.com/index.php?rid=5219865&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01954.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5219865 Thu, 15 Sep 2011 10:17:49 +0100 5219865 http://www.medworm.com/index.php?rid=5219864&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01950.x AbstractIn species in which males defend territories for breeding, males may differ in territorial behavior; alternative behaviors among territorial males are not well understood. In our long‐term study of partially‐migratory song sparrows, we have observed that most territorial males establish territories before females begin nesting and remain site‐faithful both within and between breeding seasons; however, some males establish territories later in the season (late establishers) and/or change territory locations either within or between seasons (movers). Whether late establishment or moving are equally successful strategies for territory defense, or best‐of‐bad‐job options, is not known. Here, we compare the frequencies of these behaviors to demographic variables over a 9‐y... Ethology journals http://www.medworm.com/rss/comments.php?id=5219864 Thu, 15 Sep 2011 10:17:46 +0100 5219864 http://www.medworm.com/index.php?rid=5234516&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01953.x AbstractDominance is an important determinant of reproductive success in many species, and size is usually an indicator of dominance status, with larger, dominant individuals physically and physiologically preventing smaller subordinates from mating. However, small size may be advantageous in some mating contexts because enhanced manoeuvrability enables males to get closer to females during mating. Here, we determined the paternity success and testes size of dominant and subordinate male zebrafish (Danio rerio), in pairs that controlled for social status. There was no statistical difference in both body size and testes size between dominant and subordinate males. Dominant males sired significantly more offspring than subordinates, but when subordinates were small, they had a greater share ... Ethology journals http://www.medworm.com/rss/comments.php?id=5234516 Thu, 15 Sep 2011 04:00:00 +0100 5234516 http://www.medworm.com/index.php?rid=5191820&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01951.x AbstractMany parasites with complex life cycles are known to modify their host phenotype to enhance transmission from the intermediate host to the definitive host. Several earlier studies explored these effects in acanthocephalan and trematode parasites, especially in aquatic ecosystems; however, much less is known about parasite‐mediated alterations of host behavior in terrestrial systems involving nematodes. Here, we address this gap by investigating a trophically transmitted nematode (Pterygodermatites peromysci) that uses a camel cricket (Ceuthophilus pallidipes) as the intermediate host before transmission to the final host, the white‐footed mouse (Peromyscus leucopus). In a laboratory experiment, we quantified the anti‐predatory responses of the cricket intermediate host using ... Ethology journals http://www.medworm.com/rss/comments.php?id=5191820 Wed, 31 Aug 2011 23:00:00 +0100 5191820 http://www.medworm.com/index.php?rid=5169307&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01949.x We report an extensive field study on the behavior of this remarkable fish and how it has coped with life on land. The fish occurs in great abundance above the waterline along the rocky coastlines of Micronesia. We found them to be terrestrial in all aspects of their adult daily life, but heavily constrained by large fluctuations in both tide and temperature with almost all activity limited to a brief period at mid‐tide. Despite this, the fish were highly social and data were consistent with males defending exclusive territories on land. A variety of metrics – the use of visual displays, the allometry of ornaments, and sexual dimorphism – further imply sexual selection on both sexes was strong. Despite being restricted to an extremely narrow habitable zone in which conditions change ... Ethology journals http://www.medworm.com/rss/comments.php?id=5169307 Sun, 28 Aug 2011 03:42:23 +0100 5169307 http://www.medworm.com/index.php?rid=5169308&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01948.x This study represents, to our knowledge, the first systematic test of the integrated hypothesis on wild, non‐provisioned animals. Victims of aggression were at a greater risk of receiving aggression from the former opponent or a bystander after a conflict and showed elevated anxiety. We found no such costs for the aggressor. Reconciliation reduced anxiety in the victim but did not reduce their risk of receiving aggression. Finally, relationship quality affected the occurrence of reconciliation but did not modulate post‐conflict anxiety. The results of our study show that the costs of aggression are asymmetrically distributed between the victim and the aggressor. Such differences are likely to lead to different social tactics used by the victim and the aggressor in the aftermath of a co... Ethology journals http://www.medworm.com/rss/comments.php?id=5169308 Thu, 25 Aug 2011 23:00:00 +0100 5169308 http://www.medworm.com/index.php?rid=5156902&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01945.x AbstractA major challenge in behavioural and evolutionary ecology is to understand the evolution and maintenance of consistent behavioural differences among individuals within populations, often referred to as animal ‘personalities’. Here, we present evidence suggesting that sexual selection may act on such personality differences in zebra finches (Taeniopygia guttata), as females seem to choose males on the basis of their exploratory behaviour per se, while taking into account their own personality. After observing a pair of males, whose apparent levels of exploration were experimentally manipulated, females that exhibited low‐exploratory tendencies showed no preference during mate choice for males that had appeared to be either ‘exploratory’ or ‘unexploratory’. In contrast,... Ethology journals http://www.medworm.com/rss/comments.php?id=5156902 Thu, 25 Aug 2011 10:40:20 +0100 5156902 http://www.medworm.com/index.php?rid=5156903&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01947.x AbstractAnimals respond to alarm calls by increasing their antipredator behavior; however, responses may consistently differ by age or sex. Although several adaptive explanations have been proposed to account for age‐dependent antipredator behavior, similar explanations are rarely extended to sex‐specific responses. Furthermore, no attempts have been made to quantitatively estimate the direction or magnitude of these differences across studies. Here, we use meta‐analysis to discover overall trends in the literature, as well as differences owing to experimental or population parameters. Across our sample of available studies (unfortunately biased toward rodents and primates), males respond more than females, and young respond more than adults. Furthermore, young of quickly maturing sp... Ethology journals http://www.medworm.com/rss/comments.php?id=5156903 Thu, 18 Aug 2011 23:00:00 +0100 5156903 http://www.medworm.com/index.php?rid=5156904&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01944.x In this study, we compared the risk‐taking behavior of urban and rural house sparrows (Passer domesticus) after simulated attacks by two of their important predators (sparrowhawk Accipiter nisus and domestic cat Felis catus). The birds were startled by moving dummies of these predators and respective control objects, and their risk taking was estimated as their latency to feed after the startle. We found that sparrows responded more strongly (had longer post‐startle feeding latencies) to sparrowhawk attacks than to the control object, and their responses differed between the habitats. First, risk taking of urban birds strongly decreased with age (older birds had longer latencies than young birds), while there was no such age difference in rural birds. Second, young urban birds responde... Ethology journals http://www.medworm.com/rss/comments.php?id=5156904 Wed, 17 Aug 2011 23:00:00 +0100 5156904 http://www.medworm.com/index.php?rid=5138172&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01940.x We examined the previously documented sex‐similar size of yellow‐orange ear patches in the king penguin, Aptenodytes patagonicus. This species is monogamous and pairs just before reproduction. Raising a chick requires considerable effort by both parents, as they alternate care of their single offspring with foraging at sea. The size of the ear patches appears to signal aggressive territoriality in the breeding colony for both sexes. However, experiments suggest that females prefer large patch size during mate choice, and males do not prefer this trait. We tested whether the size of the coloured ear patch was influenced by sexual selection for couples that had recently paired. We used analyses of covariance to compare the size of the ear patch to a measure of body size and then tested f... Ethology journals http://www.medworm.com/rss/comments.php?id=5138172 Wed, 17 Aug 2011 19:28:53 +0100 5138172 http://www.medworm.com/index.php?rid=5124754&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01941.x AbstractStalk‐eyed flies are classic models of how sexual selection can drive morphological and behavioral elaboration. Exaggerated ornaments born by stalk‐eyed flies could impose locomotor costs and increase susceptibility to predation; however, a previous study determined that behavior, not eye span, was the major influence on predation risk. Despite the importance of behavior, relatively little is known about how these flies avoid and deter predators. We created an ethogram of behaviors and used it to score individual interactions of male and female Teleopsis dalmanni paired with an actively foraging, generalist arachnid predator (Phidippus audax). Sequential analysis was employed to identify temporal patterns in behavior and determine how males and females differ in their approache... Ethology journals http://www.medworm.com/rss/comments.php?id=5124754 Sat, 13 Aug 2011 09:02:41 +0100 5124754 http://www.medworm.com/index.php?rid=5124753&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01937.x AbstractWhen there is an inbreeding depression, mating with a kin individual is generally considered maladaptive behaviour. However, in some conditions, the inclusive fitness benefits from inbreeding may outweigh the costs of inbreeding depression, and thus, inbreeding tolerance is often adaptive. Inbreeding depression and the effect of relatedness on mating behaviour in the West Indian sweet potato weevil Euscepes postfasciatus were examined. No significant inbreeding depression was detected as indicated by body weight and number of progeny emerging from sweet potato roots. Male mating performance (i.e. number of mating occurrences per night) was adversely affected by inbreeding depression, but the effect was low (fitness loss was 6.3%). Although there were no significant differences in l... Ethology journals http://www.medworm.com/rss/comments.php?id=5124753 Sat, 13 Aug 2011 09:02:40 +0100 5124753 http://www.medworm.com/index.php?rid=5124752&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01936.x AbstractWe evaluated the degree of reproductive isolation between laboratory populations of the seed beetle (Acanthoscelides obtectus) selected to reproduce early (E) or late (L) in life, where different levels of sexual activity and sexual discrimination have been detected. We found a significant level of behavioral isolation among populations within the E selection regime in which beetles showed enhanced early‐life fitness traits and low sexual activity. In contrast, substantially higher levels of sexual activity and an indiscriminate mating system inhibited rather than promoted pre‐zygotic isolation between the L populations. Our results indicate that the study of sexual activity levels may be crucial for understanding the first steps in the pre‐zygotic isolation among allopatric ... Ethology journals http://www.medworm.com/rss/comments.php?id=5124752 Sat, 13 Aug 2011 09:02:39 +0100 5124752 http://www.medworm.com/index.php?rid=5124751&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01929.x In this study, we assess the relationship between food quality (highly or poorly diversified food during a short period) and female choosiness towards these two types of phrases. We confirm that females discriminate between A16 and A8. Nevertheless, the difference between the number of sexual responses towards A16 and A8 is weaker among females with a poorly diversified food diet in comparison with females with a highly diversified food diet. This suggests that even a short‐term modification of condition could decrease females’ selectivity towards high‐value stimuli and increase their response rates towards low‐value signals. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5124751 Sat, 13 Aug 2011 09:02:31 +0100 5124751 http://www.medworm.com/index.php?rid=5124750&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01934.x AbstractA pair‐living social organisation can typically be explained by obligate biparental care. We investigated pair‐living in the absence of biparental care in the Australian sleepy lizard, Tiliqua rugosa, which forms exceptionally strong pair bonds. We fitted 10 lizards, five male–female pairs, with Global Positioning System (GPS) recorders and continuously monitored social associations and separations between active pair partners, based on location records taken every 10 min over 3 mo. Males temporarily separated and reunited the pair more frequently than females, but females also contributed to the maintenance of the pair bond. These behavioural data were consistent with the hypothesis that females successfully coerce males into associations with one female. Lower frequenci... Ethology journals http://www.medworm.com/rss/comments.php?id=5124750 Sat, 13 Aug 2011 09:02:29 +0100 5124750 http://www.medworm.com/index.php?rid=5124749&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01935.x AbstractThe invasion of cane toads (Rhinella marina) through Australia imperils native predators that are killed if they consume these toxic anurans. The magnitude of impact depends upon the predators’ capacity for aversion learning: toad impact is lower if predators can learn not to attack toads. In laboratory trials, we assessed whether bluetongue lizards (Tiliqua scincoides) – a species under severe threat from toads – are capable of learned taste aversion and whether we can facilitate that learning by exposing lizards to toad tissue combined with a nausea‐inducing chemical (lithium chloride). Captive bluetongues rapidly learned to avoid the ‘unpalatable’ food. Taste aversion also developed (albeit less strongly) in response to meals of minced cane toad alone. Our data sugge... Ethology journals http://www.medworm.com/rss/comments.php?id=5124749 Sat, 13 Aug 2011 09:02:27 +0100 5124749 http://www.medworm.com/index.php?rid=5124748&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01946.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5124748 Sat, 13 Aug 2011 09:02:26 +0100 5124748 http://www.medworm.com/index.php?rid=5106271&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01942.x We examined two potential causes of this association: (1) males not copulating actually expend significant energy by searching for mates and (2) males are experiencing shorter lifespan primarily because they are more inbred than hermaphrodites. We found that isolated males did indeed expend more energy than hermaphrodites, consistent with previous studies showing that males swim over twice as much as hermaphrodites when isolated. Additionally, although inbreeding was associated with reduced lifespan, outcrossed males still had shorter lifespans relative to outcrossed hermaphrodites. Thus, isolated males consistently show decreased lifespans relative to isolated hermaphrodites, which is not explainable only on the basis of level of inbreeding. We conclude that the costly searching behavior ... Ethology journals http://www.medworm.com/rss/comments.php?id=5106271 Sat, 06 Aug 2011 23:00:00 +0100 5106271 http://www.medworm.com/index.php?rid=5106270&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01943.x In this study, we examine boldness and aggression in several urban and rural populations of song sparrows (Melospiza melodia). We found that urban birds were both bolder toward humans and also showed higher levels of aggression. We found a correlation between boldness and aggression in all populations combined, but no correlation within urban populations. Our results agree with other recent studies of song sparrow behavior, suggesting that greater boldness and aggression are general features of urban song sparrow populations, and a lack of a correlation between boldness and aggression in urban habitats is a general phenomenon as well. Urban habitats may select for bold and aggressive birds, and yet the traits can vary independently. These results add to a small number of studies which find... Ethology journals http://www.medworm.com/rss/comments.php?id=5106270 Sun, 31 Jul 2011 23:00:00 +0100 5106270 http://www.medworm.com/index.php?rid=5076960&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01939.x In this study, we described prey ball escape behaviors and investigated how prey ball behaviors related to dusky dolphin, Lagenorhynchus obscurus, prey herding and capturing behaviors using above‐water and underwater video methods. Prey balls exhibited horizontal and vertical movements, both of which would have increased feeding costs for dolphins compared with feeding on stationary prey at the surface. The only prey ball behavior that we observed to precede escape was ‘funneling’ or the brief formation of a prey ball shape where the height was at least twice the width. Funneling was observed most often for large prey balls, immediately before they descended. When prey balls ascended, there was an insignificant trend for dolphins to do a greater proportion of herding passes that did ... Ethology journals http://www.medworm.com/rss/comments.php?id=5076960 Sat, 30 Jul 2011 03:49:36 +0100 5076960 http://www.medworm.com/index.php?rid=5076961&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01938.x AbstractSocial interactions often play a significant role in determining patterns of spatial use. Although snakes are generally thought of as asocial, recent spatial dispersion studies suggest that the spatial ecology of snakes may be more strongly influenced by social interactions than previously thought. We investigated the spatial behavior patterns of a western cottonmouth (Agkistrodon piscivorus) population in east Texas by uniquely combining radio‐telemetry studies on free‐ranging snakes with experimental arena trials with captive individuals from the same population. Observations from the radio‐telemetry study on free‐ranging A. piscivorus indicated that females were more gregarious than males. In the follow‐up study, spatial dispersion data from captive snakes maintained ... Ethology journals http://www.medworm.com/rss/comments.php?id=5076961 Thu, 28 Jul 2011 23:00:00 +0100 5076961 http://www.medworm.com/index.php?rid=5049086&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01932.x AbstractDifferent forms of aggression have traditionally been treated separately according to function or context (e.g., aggression towards a conspecific vs. a predator). However, recent work on individual consistency in behavior predicts that different forms of aggression may be correlated across contexts, suggesting a lack of independence. For nesting birds, aggression towards both conspecifics and nest predators can affect reproductive success, yet the relationship between these behaviors, especially in females, is not known. Here, we examine free‐living female dark‐eyed juncos (Junco hyemalis) and compare their aggressive responses towards three types of simulated intruders near the nest: a same‐sex conspecific, an opposite‐sex conspecific, and a nest predator. We also examine ... Ethology journals http://www.medworm.com/rss/comments.php?id=5049086 Fri, 22 Jul 2011 01:05:33 +0100 5049086 http://www.medworm.com/index.php?rid=5049087&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01930.x In this study we assess, in a species of songbird, the relationship in song learning between two potentially conflicting learning goals: accuracy in copying and maximization of vocal performance. In our study species, the swamp sparrow (Melospiza georgiana), vocal performance can be defined for a given song type and frequency range by the rate of note repetition (‘trill rate’), with faster trills being more difficult to sing. We trained young swamp sparrows with song models with experimentally modified trill rates and characterized both the accuracy and performance levels of copies. Our main finding is that birds elevated the trill rates of low‐performance models, but at the expense of imitative accuracy. By contrast, birds reproduced normal and high‐performance models with typical... Ethology journals http://www.medworm.com/rss/comments.php?id=5049087 Mon, 18 Jul 2011 23:00:00 +0100 5049087 http://www.medworm.com/index.php?rid=5027395&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01928.x AbstractWhen both sexes mate with multiple partners, theory predicts that males should adjust their investment in ejaculates in response to the risk and/or intensity of sperm competition. Here, we demonstrate that, in the harlequin beetle riding pseudoscorpion, Cordylochernes scorpioides, males use cues deposited on females by previous males to distinguish between virgin, once‐mated, and multiply‐mated females and adjust sperm allocation accordingly. Sperm number declined in direct proportion to the number of previous males, with virgin females receiving nearly three times more sperm than females exposed to three previous males. Given the lack of first‐male sperm precedence in C. scorpioides, this pattern is not consistent with current sperm competition models and appears best expla... Ethology journals http://www.medworm.com/rss/comments.php?id=5027395 Thu, 14 Jul 2011 23:32:24 +0100 5027395 http://www.medworm.com/index.php?rid=5027393&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01925.x In this study, we evaluated the hypothesis that in territorial disputes without physical contact, traits that maximize endurance will be important determinants of winning. To evaluate the occurrence of physical contact, we used high‐speed video recording (240 frames per second) in two previously unstudied satyrine butterflies: Hermeuptychia fallax and Moneuptychia soter. Additionally, we performed removal experiments to assess whether wing wear, body mass, fat content, and flight muscle ratio are important determinants of male residency status. We filmed a total of 23 fights in H. fallax and 10 in M. soter. Neither species employed physical contact to settle contests. In H. fallax, younger males with greater fat content accumulated in the resident role (n = 26 pairs), indicating t... Ethology journals http://www.medworm.com/rss/comments.php?id=5027393 Thu, 14 Jul 2011 23:32:22 +0100 5027393 http://www.medworm.com/index.php?rid=5027392&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01923.x AbstractIn group‐living animals, social relationships are the result of the interactions between two individuals over time and can provide fitness benefits to both the participants. Recently, components of social relationships were identified in Old World primates and ravens through the use of principal component analysis (PCA). We employed PCA to identify components that define the social relationships in two communities of wild spider monkeys in the Yucatán Peninsula, Mexico and investigated whether characteristics of the dyads, such as age combination, sex combination and kinship, had an effect on the components obtained. We found two components. Component 1 had high positive loadings of proximity, grooming and subgroup index, which may reflect value or compatibility. Embrace and agg... Ethology journals http://www.medworm.com/rss/comments.php?id=5027392 Thu, 14 Jul 2011 23:32:20 +0100 5027392 http://www.medworm.com/index.php?rid=5027390&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01933.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=5027390 Thu, 14 Jul 2011 23:32:16 +0100 5027390 http://www.medworm.com/index.php?rid=5027389&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01931.x AbstractIn oviparous species lacking parental care, successful reproduction depends on females selecting nest sites that facilitate embryonic development. Such sites may be limited in the environment, which can lead to multiple females using the same nest site simultaneously. However, there are several alternative explanations for communal nesting, including natal homing, predator satiation, and adaptive benefits to offspring. We used laboratory experiments to evaluate three hypotheses about nest‐site selection in velvet geckos (Oedura lesueurii), which often nest communally. We investigated whether the trend to nest communally is influenced by the following: (1) evidence of previous nesting (hatched eggshells); (2) body size; and/or (3) thermal regimes. When given the choice, females la... Ethology journals http://www.medworm.com/rss/comments.php?id=5027389 Thu, 14 Jul 2011 23:32:14 +0100 5027389 http://www.medworm.com/index.php?rid=5007251&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01927.x AbstractTheoretical models of prey behaviour predict that food‐limited prey engage in risk‐prone foraging and thereby succumb to increased mortality from predation. However, predation risk also may be influenced by factors including prey density and structural cover, such that the presumed role of prey hunger on predation risk may be obfuscated in many complex predator–prey systems. Using a tadpole (prey) – dragonfly larva (predator) system, we determined relative risk posed to hungry vs. sated prey when both density and structural cover were varied experimentally. Overall, prey response to perceived predation risk was primarily restricted to increased cover use, and hungry prey did not exhibit risk‐prone foraging. Surprisingly, hungry prey showed lower activity than sated prey w... Ethology journals http://www.medworm.com/rss/comments.php?id=5007251 Thu, 30 Jun 2011 23:00:00 +0100 5007251 http://www.medworm.com/index.php?rid=4975109&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01926.x AbstractAnimals are often threatened by predators, parasites, or competitors, and attacks against these enemies are a common response, which can help to remove the danger. The costs of defense are complex and involve the risk of injury, the loss of energy/time, and the erroneous identification of a friend as a foe. Our goal was to study the specificity of defense strategies. We analyzed the aggressive responses of ant colonies by confronting them with workers of an unfamiliar congeneric species, a non‐nestmate conspecific, a co‐occurring congeneric competitor species, and a social parasite—a slave‐making ant. As expected, the latter species, which can inflict dramatic fitness losses to the colony, was treated with most aggression. A co‐occurring competitor was also attacked, but ... Ethology journals http://www.medworm.com/rss/comments.php?id=4975109 Tue, 28 Jun 2011 20:52:31 +0100 4975109 http://www.medworm.com/index.php?rid=4975110&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01924.x AbstractFood caching animals depend on their caches at times of low food availability. Because stored food is susceptible to being stolen or degraded, many species employ cache protection strategies such as ceasing caching in the presence of others or avoiding storing perishable items for long periods. Several species frequently recover their caches and recache, which may reduce pilferage or degradation of cached items. We studied the food handling decisions of Florida scrub‐jays (Aphelocoma coerulescens) after cache recovery to determine the roles that social and ecological environments play in post‐recovery decisions. Instead of reducing recaching in the presence of others, recovering jays flew away from the recovery site, allowing them to eat or recache a recovered item regardless o... Ethology journals http://www.medworm.com/rss/comments.php?id=4975110 Sun, 26 Jun 2011 23:00:00 +0100 4975110 http://www.medworm.com/index.php?rid=4933089&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01917.x AbstractMost theoretical models of coevolution between brood parasites, whether interspecific or conspecific, and their hosts explicitly assume consistent individual behaviour in host egg‐rejection responses. Accordingly, hosts cast as acceptors always accept, whereas ejectors always reject parasitic eggs when exposed to stable ecological conditions. To date, only few studies have attempted to test this critical assumption of individual repeatability in egg‐rejection responses of hosts. Here, we studied the repeatability of egg rejection in blackbirds (Turdus merula) and song thrush (T. philomelos), species in which females are reported to reject simulated, non‐mimetic foreign eggs at intermediate frequencies at the population level. However, intermediate rates of acceptance and rej... Ethology journals http://www.medworm.com/rss/comments.php?id=4933089 Thu, 16 Jun 2011 22:59:27 +0100 4933089 http://www.medworm.com/index.php?rid=4933088&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01921.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4933088 Thu, 16 Jun 2011 22:59:25 +0100 4933088 http://www.medworm.com/index.php?rid=4933086&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01922.x AbstractThe state of the environment parents are exposed to during reproduction can either facilitate or impair their ability to take care of their young. Thus, the environmental conditions experienced by parents can have a transgenerational impact on offspring phenotype and survival. Parental energetic needs and the variance in offspring predation risk have both been recognized as important factors influencing the quality and amount of parental care, but surprisingly, they are rarely manipulated simultaneously to investigate how parents adjust care to these potentially conflicting demands. In the maternally mouthbrooding cichlid Simochromis pleurospilus, we manipulated female body condition before spawning and exposure to offspring predator cues during brood care in a two‐by‐two facto... Ethology journals http://www.medworm.com/rss/comments.php?id=4933086 Thu, 16 Jun 2011 22:59:23 +0100 4933086 http://www.medworm.com/index.php?rid=4933087&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01919.x AbstractRecent studies have suggested that domestic dogs (Canis familiaris) engage in highly complex forms of social learning. Here, we critically assess the potential mechanisms underlying social learning in dogs using two problem‐solving tasks. In a classical detour task, the test dogs benefited from observing a demonstrator walking around a fence to obtain a reward. However, even inexperienced dogs did not show a preference for passing the fence at the same end as the demonstrator. Furthermore, dogs did not need to observe a complete demonstration by a human demonstrator to pass the task. Instead, they were just as successful in solving the problem after seeing a partial demonstration by an object passing by at the end of the fence. In contrast to earlier findings, our results suggest... Ethology journals http://www.medworm.com/rss/comments.php?id=4933087 Mon, 13 Jun 2011 23:00:00 +0100 4933087 http://www.medworm.com/index.php?rid=4920581&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01920.x AbstractEarly behaviour can determine food intake and growth rate with important consequences for life history and survival in fishes. Egg size is known to affect growth rate of young Arctic charr but its influence on the development of behaviour is poorly documented. It is believed that egg size influence on growth and potentially on the behaviour of young fish decreases over time, minimized by the effects of social factors. Shortly after first feeding, we examined differences in mobility and foraging of Arctic charr in relation to egg size and social environment. The behaviour of juveniles from small and large eggs was compared five times over the course of development and in three different experimental settings: long‐term isolation (isolation before hatching), short‐term isolation ... Ethology journals http://www.medworm.com/rss/comments.php?id=4920581 Tue, 31 May 2011 23:00:00 +0100 4920581 http://www.medworm.com/index.php?rid=4871341&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01918.x AbstractHoney bee, Apis mellifera, entrance guards use chemical cues to discriminate nestmates from non‐nestmates. Previous research has shown that when wax combs are reciprocally swapped between two colonies, guards become more accepting of workers from the swap partner. However, when combs were transferred only one way, guards in the comb‐receiver colony became more accepting of bees from the comb‐donor colony, but not vice versa. Hence, the increased acceptance of non‐nestmates caused by reciprocal comb swapping was not because of introduced bees acquiring odours from the transferred combs, which was surprising because comb wax was known to affect the odour of bees. In the current experiment, we caused workers to acquire either nestmate or non‐nestmate odours by holding them f... Ethology journals http://www.medworm.com/rss/comments.php?id=4871341 Fri, 27 May 2011 23:55:56 +0100 4871341 http://www.medworm.com/index.php?rid=4840489&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01916.x AbstractMating systems that comprise a mixture of pure males and self‐fertilising hermaphrodites remain an evolutionary enigma. In particular, our understanding of the sexual selection pressures associated with such mating systems is nascent. Males can only reproduce by fertilising hermaphrodites’ eggs, but hermaphrodites can also fertilise their own eggs and gain a genetic advantage by doing so. Consequently, there should be intense competition among males to access hermaphrodites. Here, we test the importance of male size, colour and heterozygosity in predicting the outcome of male–male competition using the mangrove rivulus, which has a male‐hermaphrodite mixed‐mating system. We pitted males against one another in dyadic laboratory trials to develop a dominance score for each ... Ethology journals http://www.medworm.com/rss/comments.php?id=4840489 Thu, 19 May 2011 21:34:12 +0100 4840489 http://www.medworm.com/index.php?rid=4840493&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01914.x AbstractIn insects, spermatophore production represents a non‐trivial cost to a male. Non‐virgin males have been shown to produce small spermatophores at subsequent matings. Particularly in monandrous species, it may be an issue to receive a sufficiently large spermatophore at the first and typically only mating. Females of the monandrous Speckled wood butterfly Pararge aegeria (L.) produce fewer offspring after mating with a non‐virgin male. After mating, females spend all their active time selecting oviposition sites and typically ignore other males. Here, we show that females did not discriminate between a virgin male and a recently mated male in our laboratory experiments. We demonstrate that the number of eupyrene sperm bundles relative to spermatophore mass differed with subseq... Ethology journals http://www.medworm.com/rss/comments.php?id=4840493 Mon, 16 May 2011 23:00:00 +0100 4840493 http://www.medworm.com/index.php?rid=4840492&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01909.x AbstractIn harem‐polygynous societies, body condition is often correlated with dominance rank. However, the consequences of dominance are less clear. High‐ranking males do not inevitably have the highest reproductive success, especially in systems where females mate with multiple males. In such societies, we expect male reproductive success to be more highly skewed than female reproductive success, but reproductive skew in females can still arise from rankings established within matrilineal societies. Dominance can also impact life‐history decisions by influencing dispersal patterns in yearlings. To better understand the function of dominance in harem‐polygynous societies, we studied the causes and consequences of dominance in yellow‐bellied marmots (Marmota flaviventris), a soci... Ethology journals http://www.medworm.com/rss/comments.php?id=4840492 Mon, 16 May 2011 23:00:00 +0100 4840492 http://www.medworm.com/index.php?rid=4840491&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01912.x AbstractMales of many butterfly species persistently court and attempt to mate with females even if the females reject courtship. This male harassment almost certainly has negative effects on female fitness. Therefore, females have likely evolved strategies to avoid such encounters. To investigate the harassment avoidance strategy of females of the small copper butterfly, Lycaena phlaeas daimio, I observed the reactions of females to other individuals flying nearby in the field. In response to the conspecific butterflies, females closed their wings if they had previously been open and did not exhibit any action if the wings had been closed. Females that closed their open wings in response to a conspecific received fewer mating attempts than did females that held their wings open. These res... Ethology journals http://www.medworm.com/rss/comments.php?id=4840491 Mon, 16 May 2011 23:00:00 +0100 4840491 http://www.medworm.com/index.php?rid=4840490&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01913.x AbstractThe number of group members in an animal society can have a major influence on group members’ life history, survival, and reproductive success. Identifying the factors that limit group size is therefore fundamental for a complete understanding of social behavior. Here, I examined the relationships between resource availability, social conflict, and group size in the coral‐dwelling fish, Paragobiogon xanthosomus (Gobiidae). The size of the largest (breeding) female and the minimum size difference required for hierarchy stability strongly but not perfectly predicted maximum group size, suggesting that social conflicts and hierarchy structure set the upper limit on group size. Deviations in group size around the predicted maximum were explained by variation in average body size ra... Ethology journals http://www.medworm.com/rss/comments.php?id=4840490 Mon, 16 May 2011 23:00:00 +0100 4840490 http://www.medworm.com/index.php?rid=4812519&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01908.x AbstractThe aim of this experiment was to investigate differences in spacing behaviour, measured by the individual distance when resting and feeding, between two breeds of sheep with a different selection history. Eight groups of four pregnant ewes from the Nor‐X breed (a heavy, composite breed mainly selected for growth and meat quality) and eight groups of four pregnant ewes of the coloured Spæl breed (a light breed, mainly selected for wool quality) were placed in oblong experimental pens for 7 d. The distance between animals was measured from digital video recordings. The heavy Nor‐X ewes kept a significantly larger individual distance to their pen mates both during resting and feeding compared with the lighter Spæl ewes. Spæl ewes also kept a significantly smaller individual ... Ethology journals http://www.medworm.com/rss/comments.php?id=4812519 Thu, 12 May 2011 07:13:28 +0100 4812519 http://www.medworm.com/index.php?rid=4801874&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01907.x AbstractTerritorial disputes are frequently settled by an advantage afforded to one of the contestants by asymmetries such as size difference, strength and motivation. Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus) are reported to defend cover objects, a form of territorial behaviour. We conducted an experiment to determine whether or not adult salamanders of this species exhibit prior residence effect during staged encounters involving size‐matched, same sex conspecifics (i.e. does familiarity with a territory predict successful defence?). We tested 154 adult salamanders (72 female, 82 male) in reciprocal trials in which each animal acted as a resident and as an intruder. We recorded multiple agonistic behaviours including: front‐trunk raised, all‐trunk raised, nudg... Ethology journals http://www.medworm.com/rss/comments.php?id=4801874 Tue, 10 May 2011 00:06:08 +0100 4801874 http://www.medworm.com/index.php?rid=4801873&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01910.x AbstractInsect societies are normally closed entities from which alien individuals are excluded. The occasional fusion of unrelated colonies of the thelytokous ant Platythyrea punctata is therefore puzzling, because it strongly intensifies competition among nestmates for the replacement of an old reproductive. Most colonies of P. punctata have only one or few reproductives, which produce female offspring from unfertilized eggs, and therefore have a clonal structure. Fusion leads to multi‐clone colonies. We compared the occurrence of dominance and policing behavior between single‐ and double‐clone colonies. We find that the frequency of aggression is higher in double‐clone colonies, but that individuals do not preferentially direct attacks toward non‐clonemates. This matches obse... Ethology journals http://www.medworm.com/rss/comments.php?id=4801873 Tue, 10 May 2011 00:06:05 +0100 4801873 http://www.medworm.com/index.php?rid=4801872&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01906.x AbstractDivision of labor is a strategy that maximizes the foraging and reproductive success of eusocial insects. Although some arachnids exhibit colony structure and social organization similar to that of hymenopterans, temporal polyethism has only been demonstrated in few species. The social organization of cooperative pseudoscorpions Paratemnoides nidificator is similar to that of social spiders, but it involves a clear division of labor. Work allocation was experimentally investigated in colonies composed of only one developmental stage (young or adults) or by one sex (males or females), through laboratory manipulation. During 44 h of observation, more than 14 000 behavioral repetitions were quantified, distributed in 95 different types of behavioral acts, and grouped in 10 behavio... Ethology journals http://www.medworm.com/rss/comments.php?id=4801872 Tue, 10 May 2011 00:06:00 +0100 4801872 http://www.medworm.com/index.php?rid=4801871&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01896.x AbstractWe studied anti‐predator strategies in nine species of tarantulas from Asia, Africa, and the Americas. Tarantulas in the New World possess urticating hairs which induce inflammation when in contact with vertebrate mucus membranes and skin. In contrast, tarantulas from the Old World lack this defense but are observed to exhibit a much greater willingness to escalate to an active defense when provoked. We had three goals: (1) describe the behaviors exhibited by each taxon in response to two levels of provocation, (2) look for the presence of alternative classes of anti‐predator strategy as predicted by the Old World–New World dichotomy in aggressive defense, and (3) examine the evolution of these behaviors in the context of the phylogeny of the group. We compared the response o... Ethology journals http://www.medworm.com/rss/comments.php?id=4801871 Tue, 10 May 2011 00:05:58 +0100 4801871 http://www.medworm.com/index.php?rid=4801870&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01915.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4801870 Tue, 10 May 2011 00:05:57 +0100 4801870 http://www.medworm.com/index.php?rid=4758367&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01911.x AbstractEscape theory predicts that flight initiation distance (predator–prey distance when escape begins) increases as predation risk increases and decreases as cost of fleeing increases. Scant information is available about the effects of some putative predation risk factors and about interaction between simultaneously operating risk and cost of fleeing factors on flight initiation distance and distance fled. By simulating an approaching predator, I studied the effects of body temperature (BT), distance to nearest refuge, and eye contact with a predator, as well as simultaneous effects of predator approach speed and female presence/absence on escape behavior by a small ectothermic vertebrate, the lizard Sceloporus virgatus. Flight initiation distance decreased as BT increased, presumab... Ethology journals http://www.medworm.com/rss/comments.php?id=4758367 Thu, 28 Apr 2011 05:20:48 +0100 4758367 http://www.medworm.com/index.php?rid=4747268&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01902.x AbstractUrbanization creates challenges for wildlife, most notably through changes in resource availability and the frequent occurrence of sensory disturbance. Some native species, however, have been able to exploit and thrive in urban environments. Research, in this regard, has mostly focused on the ecological conditions that have allowed such species to prosper. In contrast, less attention has been devoted to evaluating how they cope with human proximity and disturbance. In a field experiment on a successful Australian ‘urban adapter’, the Noisy miner, Manorina melanocephala, we compared tolerance of a loud, startling sound stimulus by urban and rural individuals. We found group size differences between birds occupying urban and rural sites: more urban birds came into the testing are... Ethology journals http://www.medworm.com/rss/comments.php?id=4747268 Mon, 25 Apr 2011 14:47:41 +0100 4747268 http://www.medworm.com/index.php?rid=4733265&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01905.x AbstractFemales of some cooperative‐breeding species can decrease their egg investment without costs for their offspring because helpers‐at‐the‐nest compensate for this reduction either by feeding more or by better protecting offspring from predation. We used the southern lapwing (Vanellus chilensis) to evaluate the effects of the presence of helpers on maternal investment. Southern lapwings are cooperative (some breeding pairs are aided by helpers), chick development is precocial, thus adults do not feed the chicks, and adults offer protection from predators through mobbing behaviors. We tested whether southern lapwing females reduced their reproductive investment (i.e. load‐lightening [LL] hypothesis) or increased their investment (i.e. differential allocation hypothesis) when ... Ethology journals http://www.medworm.com/rss/comments.php?id=4733265 Thu, 21 Apr 2011 14:54:42 +0100 4733265 http://www.medworm.com/index.php?rid=4708886&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01901.x We examined newly hatched larvae, overwintered larvae and ovipositing females to test hypotheses predicting when host‐plant choice takes place (overwintering and mobility hypotheses: overwintering stage determines choice of substrate vs. most mobile stage chooses) and the basis for choice (optimal oviposition and enemy‐free space hypotheses: resource producing highest fecundity vs. lowest losses to enemies). We also evaluated the hypothesis that host‐associated fitness trade‐offs explain host specialization. Only ovipositing females, the most mobile stage, exhibited a clear preference (for marsh fern), consistent with the mobility hypothesis. However, their preference for marsh fern fits neither the optimal oviposition hypothesis nor the enemy‐free space hypothesis; although some... Ethology journals http://www.medworm.com/rss/comments.php?id=4708886 Thu, 14 Apr 2011 06:51:15 +0100 4708886 http://www.medworm.com/index.php?rid=4708887&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01900.x AbstractDiscrimination of foreign eggs is one of the most studied aspects of host defences against avian brood parasites. Although many factors affecting host egg‐recognition processes have already been evaluated, only a few attempts have been made to test the importance of light conditions in microhabitats of host nests. Here, we examined whether the objectively measured nest light environment affects great reed warbler (Acrocephalus arundinaceus) responses towards real common cuckoo (Cuculus canorus) eggs. More specifically, we predicted that parasitic eggs will be rejected with a lower frequency from nests placed in darker conditions than those in lighter conditions. However, we found no effect of the ambient light on egg‐rejection behaviour alone, but the photosynthetically active ... Ethology journals http://www.medworm.com/rss/comments.php?id=4708887 Tue, 12 Apr 2011 23:00:00 +0100 4708887 http://www.medworm.com/index.php?rid=4683527&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01904.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4683527 Thu, 07 Apr 2011 16:26:58 +0100 4683527 http://www.medworm.com/index.php?rid=4683526&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01903.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4683526 Thu, 07 Apr 2011 16:26:51 +0100 4683526 http://www.medworm.com/index.php?rid=4683524&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01898.x AbstractSexual conflict is implicated in the evolution of nuptial feeding. One function of nuptial gifts lies in mating effort, where the female’s eating of the gift reduces her likelihood of prematurely terminating sperm transfer. We test several ideas regarding sexual conflict in the nuptially feeding wood cricket Nemobius sylvestris. In this cricket, males pass two kinds of spermatophores to females: spermless microspermatophores and larger sperm‐filled macrospermatophores. Females may palpate the males’ forewing secretions as a possible additional form of nuptial feeding. We manipulated male mobility and female feeding regime to examine the effects on spermatophore transfer, macrospermatophore attachment duration, and palpations of the males’ forewings. Neither male confinement... Ethology journals http://www.medworm.com/rss/comments.php?id=4683524 Thu, 07 Apr 2011 16:26:49 +0100 4683524 http://www.medworm.com/index.php?rid=4683525&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01899.x AbstractBirds may sing from positions in the vegetation (song posts) to allow efficient transmission of sexual and territorial vocal displays while simultaneously minimizing the risk of predation because of avian and mammalian predators. Because urban areas are deficient in specialized avian predators, but have many cats while the opposite is the case for nearby rural areas, urban birds should display higher in the vegetation. In a comparison of the abundance of predators in three cities (Oslo, Brønderslev, Orsay), I show that avian predators are more common in rural areas, while mammalian predators are more common in urban areas. Singing birds sang from higher positions in the vegetation of urban than nearby rural areas. Differences in song post heights between urban and rural areas were... Ethology journals http://www.medworm.com/rss/comments.php?id=4683525 Mon, 04 Apr 2011 23:00:00 +0100 4683525 http://www.medworm.com/index.php?rid=4676315&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01897.x AbstractAnimals can use signals emitted by other animals as sources of information. Auditory signals are important in communication networks, as they can potentially convey information about the location and state of conspecifics and other species over long distances. Signalling is important in fission–fusion societies, in which animals from the same social group temporarily split into subgroups and frequently change roost sites. We used playbacks of social calls of the noctule Nyctalus noctula produced in roosts, to show how bats might maintain group cohesion and to test the hypothesis that noctules can locate conspecifics when returning from foraging trips by eavesdropping on or communicating with roosting individuals. Noctules responded strongly to broadcasted social calls. Their reac... Ethology journals http://www.medworm.com/rss/comments.php?id=4676315 Thu, 31 Mar 2011 23:00:00 +0100 4676315 http://www.medworm.com/index.php?rid=4642043&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01887.x In this study, we compare male vs. female territorial singing behaviour in Neotropical rufous‐and‐white wrens Thryothorus rufalbus, a species where both sexes produce solo songs and often coordinate their songs in vocal duets. We recorded free‐living birds in Costa Rica using an eight‐microphone Acoustic Location System capable of passively triangulating the position of animals based on their vocalizations. We recorded 17 pairs of birds for 2–4 consecutive mornings and calculated the territory of each individual as a 95% fixed kernel estimate around their song posts. We compared territories calculated around male vs. female song posts, including separate analyses of solo vs. duet song posts. These spatial analyses of singing behaviour reveal that males and females use similarly s... Ethology journals http://www.medworm.com/rss/comments.php?id=4642043 Mon, 28 Mar 2011 17:52:06 +0100 4642043 http://www.medworm.com/index.php?rid=4631182&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01888.x This study evaluates red eyes as a social and biological cue by contrasting the perception of eyes with normal ‘whites’ with copies of those eyes whose sclera were reddened by digital editing. Individuals with reddened sclera were perceived as sadder, less healthy, and less attractive than individuals with normal (white) sclera. Scleral whiteness joins such cues as smooth skin, long, lustrous hair, symmetry, averageness and sexually dimorphic traits as signs of health, beauty and reproductive fitness. (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4631182 Fri, 25 Mar 2011 03:43:15 +0100 4631182 http://www.medworm.com/index.php?rid=4621840&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01895.x AbstractColony reproduction in honey bees involves complex interactions between sterile workers and reproductive castes. Although worker–queen interactions have been studied in detail, worker–drone interactions are less well understood. We investigated caste interactions in honey bees by determining the age and behavior of workers that perform vibration signals, trophallaxis, and grooming with drones. Workers of all ages could engage in the different interactions monitored, although workers that performed vibration signals on drones were significantly older than those engaging in trophallaxis and grooming. Only 3–8% of workers engaged in the different behaviors were monitored. Compared with workers that performed vibration signals only on workers (‘worker vibrators’), those that ... Ethology journals http://www.medworm.com/rss/comments.php?id=4621840 Wed, 23 Mar 2011 02:50:03 +0100 4621840 http://www.medworm.com/index.php?rid=4614828&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01891.x AbstractMale and female mating preferences are commonly inferred from association times spent with potential mates in a dichotomous‐choice test. However, this assessment method is rarely validated, particularly so for male mating preferences. Using the Trinidadian guppy (Poecilia reticulata), an important model species in the study of sexual selection, we tested whether a male’s mating preference for either of two stimulus females in a dichotomous‐choice test predicted his mating behaviours directed at the preferred female when he was allowed to swim freely with both females. First, we presented individual males with two females that differed in body length in a dichotomous‐choice apparatus in which the male could only use visual cues to assess the paired females. We quantified mal... Ethology journals http://www.medworm.com/rss/comments.php?id=4614828 Mon, 21 Mar 2011 17:47:47 +0100 4614828 http://www.medworm.com/index.php?rid=4605541&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01894.x In this study, we examined the effect of paternal reproductive tactic on juvenile behaviour and kin discrimination in Chinook salmon. We created maternal half‐sibling families by collecting eggs from mature females and fertilizing one‐half with the milt of a precocious 2‐yr‐old male and the other half with the milt of a non‐precocious 4‐yr‐old male. These families were reared in full‐sibling groups for approximately 9 mo, and social interactions were then observed in groups of six fish of mixed relatedness. We found evidence for kin discrimination, as significantly less aggression was directed towards related fish than unrelated fish, and the same trends were observed regardless of whether social interactions included full‐siblings or half‐siblings. These results show... Ethology journals http://www.medworm.com/rss/comments.php?id=4605541 Fri, 18 Mar 2011 04:44:34 +0100 4605541 http://www.medworm.com/index.php?rid=4600115&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01890.x AbstractBurrow architecture enhances important animal functions such as food storage, predator avoidance, and thermoregulation. Occupants may be able to maximize fitness by remodeling burrows in response to seasonal changes in climate and predation risk. My objective was to examine how banner‐tailed kangaroo rats (Dipodomys spectabilis) modify the number of burrow entrances in response to seasonal conditions. For 3 yr, I monitored fluctuations in number of burrow entrances in kangaroo rat mounds. Individual kangaroo rats continually remodeled mounds in response to seasonal conditions. Compared to summer, mounds in winter had approximately 50% fewer entrances and plugged entrances were common. Monthly differences in number of entrances were closely linked with seasonal changes in soil t... Ethology journals http://www.medworm.com/rss/comments.php?id=4600115 Thu, 17 Mar 2011 02:27:39 +0100 4600115 http://www.medworm.com/index.php?rid=4600117&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01889.x In this study, we investigated the effects of simulated predation risk on mate choice in túngara frogs, Physalaemus pustulosus, using the advertisement calls of predatory frogs, variation in ambient light, and simulated distance. Females showed aversion to conspecific calls associated with the calls of predators, and females were significantly less likely to travel perceived longer distances while the calls of predatory frogs were broadcast. In both the laboratory and field, females chose among potential mates significantly faster under higher light levels. Female responses to acoustic cues of predation risk were significantly influenced by light level, but decisions about travel distances were not. These results demonstrate that female choice is strongly influenced by perceived predation... Ethology journals http://www.medworm.com/rss/comments.php?id=4600117 Wed, 16 Mar 2011 00:00:00 +0100 4600117 http://www.medworm.com/index.php?rid=4600116&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01893.x AbstractOne prediction from life‐history theory is that males should increase investment in reproductive effort as they age because the opportunity for future reproductive events declines. However, older males may not be able to increase their reproductive effort if condition declines with age. The effect of age‐related changes in condition may be especially important for energetically costly activities such as moving within and between habitat patches while searching for mates. Although such searching is a component of many mating systems, the relationship between age and active mate searching has not been investigated. We investigated whether mate‐searching effort increased with age in the thornbug treehopper, Umbonia crassicornis (Hemiptera: Membracidae). In this species, males se... Ethology journals http://www.medworm.com/rss/comments.php?id=4600116 Wed, 16 Mar 2011 00:00:00 +0100 4600116 http://www.medworm.com/index.php?rid=4565638&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01892.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4565638 Thu, 10 Mar 2011 02:08:58 +0100 4565638 http://www.medworm.com/index.php?rid=4565637&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01885.x In this study, we used wood frogs (Rana sylvatica) to test whether exposure to cues indicating predation risk from dragonfly larvae during the wood frog larval stage affected post‐metamorphic activity level and avoidance of garter snake chemical cues. Dragonfly larvae prey upon wood frogs only during the larval stage, whereas garter snakes prey upon wood frogs during both the larval stage and the post‐metamorphic stage. Exposure to predation risk from dragonflies during the larval stage caused post‐metamorphic wood frog juveniles to have greater terrestrial activity than juvenile wood frogs that were not exposed to larval‐stage predation risk from dragonflies. However, exposure to predation risk as larvae did not affect juvenile wood frog responses to chemical cues from garter snak... Ethology journals http://www.medworm.com/rss/comments.php?id=4565637 Thu, 10 Mar 2011 02:08:54 +0100 4565637 http://www.medworm.com/index.php?rid=4559747&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01886.x AbstractEnvironmental conditions experienced early in life have been shown to significantly affect growth trajectories at later stages in many vertebrate species. Amphibians typically have a biphasic life history, with an aquatic larval phase during early development and a subsequent terrestrial adult phase after completed metamorphosis. Thus, the early conditions have an especially strong impact on the future survival and fitness of amphibians. We studied whether early nutritional conditions affect the behavioural reaction of fire salamander larvae (Salamandra salamandra) before completion of metamorphosis. Fire salamander larvae reared under rich nutritional conditions were heavier and larger, displayed better body condition overall throughout the first three month of life and metamorpho... Ethology journals http://www.medworm.com/rss/comments.php?id=4559747 Tue, 01 Mar 2011 00:00:00 +0100 4559747 http://www.medworm.com/index.php?rid=4531627&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01882.x AbstractRecent years have seen an explosion in the diversity of partner control mechanisms hypothesised to stabilise cooperative behaviour among unrelated individuals. Game theory suggests numerous strategies, each with specific decision rules that allow cooperators to control a non‐contributing partner. This diversity of hypothetical strategies seems likely to reflect diversity in the types of intraspecific cooperation and interspecific mutualism that exist in nature. It is therefore important to provide a framework that explains similarities and differences between the various hypothetical strategies and that predicts how key parameters that describe the natural history of natural systems favour different control mechanisms. We develop a novel unifying framework for pairwise interactio... Ethology journals http://www.medworm.com/rss/comments.php?id=4531627 Tue, 01 Mar 2011 00:00:00 +0100 4531627 http://www.medworm.com/index.php?rid=4531626&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01884.x AbstractMultiple signals that convey different messages have been reported in many taxa, but relatively few studies have been made on such signals in invertebrates. In the present study, I investigated four types of claw‐waving display used in the fiddler crab Uca lactea to test whether the displays have different functions. Three males with a sand structure beside their burrows (which can attract females) and three males without a sand structure were fenced in an opaque enclosure, and I videotaped their waving displays after releasing two burrowless males or two burrowless females to test the effects of audiences. (a) Lateral‐circular waving tended to occur in enclosures with burrowless females and was performed frequently by males that had sand structures. (b) Lateral‐flick waving ... Ethology journals http://www.medworm.com/rss/comments.php?id=4531626 Tue, 01 Mar 2011 00:00:00 +0100 4531626 http://www.medworm.com/index.php?rid=4511913&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01883.x AbstractAlarm calling by parents is widespread among animals and has strong implications for parent and offspring fitness, yet it is virtually unknown whether parental alarm calls can initiate a corticosterone response in offspring. We investigated whether parental alarm calls of the white‐crowned sparrow, Zonotrichia leucophrys, activated the corticosterone response of their nest‐bound young, as such a response might prepare older nestlings for premature fledging and increase their survival when contacted by a predator at the nest. We conducted an experiment in which nestlings were either exposed to parent alarm calls (treatment) or experienced a period without parental alarm calls (control) immediately prior to blood sampling. We then sampled nestlings to measure corticosterone level... Ethology journals http://www.medworm.com/rss/comments.php?id=4511913 Thu, 24 Feb 2011 01:23:14 +0100 4511913 http://www.medworm.com/index.php?rid=4464253&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01881.x AbstractGrowing evidence that female ornaments and armaments may be important for female reproductive success suggests that a reevaluation of the costs of these potentially sexually selected traits is also necessary. Here, I examine whether intrasexual aggression, a trait favored during direct female–female competition for nesting sites in tree swallows (Tachycineta bicolor), is costly in terms of the quantity or quality of offspring. I compared measures of female aggressiveness to clutch size, and I also cross‐fostered offspring just after hatching to explore a possible causal link between female aggression and nestling mass, an established proxy for offspring quality. High levels of aggression in females were not associated with the quantity of offspring, but instead more aggressive ... Ethology journals http://www.medworm.com/rss/comments.php?id=4464253 Sat, 12 Feb 2011 01:26:36 +0100 4464253 http://www.medworm.com/index.php?rid=4455012&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01880.x AbstractIndicators of individual quality in ornamentation or in vocalizations have been reported for different animal species. However, no studies have jointly investigated ornamentation and vocalizations in one species. The crested auklet (Aethia cristatella, Alcidae) is a small colonial seabird of the North Pacific and is unusual for a bird in using optical, vocal, and olfactory signals. We estimated the potential for coding individual quality in vocalizations and plumage ornamentation and the relationship between vocal and optical traits in crested auklets. During the summer seasons of 2008–2009, we recorded 359 trumpet calls from 28 individually marked males and measured indices of body size, condition, and plumage patterns of 58 male and 48 female crested auklets from a breeding col... Ethology journals http://www.medworm.com/rss/comments.php?id=4455012 Thu, 10 Feb 2011 01:03:06 +0100 4455012 http://www.medworm.com/index.php?rid=4449995&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01876.x AbstractThe colour of blue‐green bird eggs has been hypothesized to signal female quality to attending males, who may adjust their level of investment in the brood accordingly. The hypothesis has gained support in studies of Spanish pied flycatchers Ficedula hypoleuca. We performed a cross‐fostering experiment in a Norwegian population of pied flycatchers to provide an independent test of the sexually selected egg colour hypothesis in this species. Egg colour was not significantly correlated with estimates of female quality (clutch size, average egg volume, first egg laying date and feeding rate). There was a significant decrease in chroma and increase in brightness and egg volume during the laying sequence, with some marked differences between six‐egg and seven‐egg clutches that m... Ethology journals http://www.medworm.com/rss/comments.php?id=4449995 Wed, 09 Feb 2011 00:37:54 +0100 4449995 http://www.medworm.com/index.php?rid=4449997&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01877.x AbstractAlthough in recent years behavioral syndromes have received a wealth of attention, how traits within syndromes respond to changing environments is not well resolved. Here, we test the effects of temperature on a suite of behavioral traits in the spider Anelosimus studiosus to determine (1) whether there are shifts in individuals’ social tendency, activity level, and foraging behavior in response to temperature, (2) if these traits shift are in the direction predicted by within‐population axes of trait covariance, and (3) whether the effects of temperature differ among individuals. In previous work, we documented a behavioral syndrome in A. studiosus where increased tolerance of conspecifics is correlated with decreased activity level and aggressiveness toward prey. Furthermore... Ethology journals http://www.medworm.com/rss/comments.php?id=4449997 Mon, 07 Feb 2011 00:00:00 +0100 4449997 http://www.medworm.com/index.php?rid=4449996&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01878.x AbstractVigilance is a behavioural tactic that allows individuals to control their surroundings and to assess predation risk. In contrast, sleep is unique behavioural state with widely hypothesized restorative and energy‐saving functions, but reducing attentiveness and increasing susceptibility to predation. Sleeping birds resolve this conflict by interrupting sleep with short periods of eye opening (termed ‘scans’) during vigilant sleep. Miscellaneous environmental factors and sleeping postures may affect the perception of risk and corresponding vigilance level. Here, we investigated the influence of nest vegetation concealment, time of day and sleeping postures on the sleep/vigilance trade‐off in incubating Mallards (Anas platyrhynchos). We found that incubating females increased... Ethology journals http://www.medworm.com/rss/comments.php?id=4449996 Mon, 07 Feb 2011 00:00:00 +0100 4449996 http://www.medworm.com/index.php?rid=4428717&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2010.01879.x (Source: Ethology) Ethology journals http://www.medworm.com/rss/comments.php?id=4428717 Thu, 03 Feb 2011 00:35:24 +0100 4428717 http://www.medworm.com/index.php?rid=4423864&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01874.x In this study, acoustic variables (formants, fundamental frequency, duration and power quartiles) of 480 oral and 483 nasal calls, recorded from 20 (9 male, 11 female) individually identified captive juvenile goitred gazelles, were examined for their potential to encode sex and identity of the caller. Discriminant function analysis revealed an equally high potential of oral and nasal calls to encode sex, whereas encoding the individual identity was significantly more accurate for oral calls. Sex was encoded exclusively in formants, whilst individual identity was encoded in a combination of all investigated variables. No correlation was found between body mass and values of any acoustic variable. Analyses controlling for age and sex revealed higher average values for all investigated variab... Ethology journals http://www.medworm.com/rss/comments.php?id=4423864 Tue, 01 Feb 2011 00:00:00 +0100 4423864 http://www.medworm.com/index.php?rid=4405277&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01875.x AbstractHow should animals sleep in groups? Because sleeping reduces the ability of an individual to detect potential threats, not all individuals should sleep at the same time. The obvious solution of taking turns to sleep is not documented in animal groups. Individuals can also organize their sleeping bouts independently of each other but this simple strategy can be dangerous if too many individuals happen to sleep at the same time. One solution to this problem is to monitor the behaviour of other group members and adjust sleeping bouts accordingly. For instance, as the number of sleeping individuals increases, companions may decide that it must be a safe time to sleep. However, when fewer group members are sleeping, an individual may benefit by curtailing sleep, given that it would be m... Ethology journals http://www.medworm.com/rss/comments.php?id=4405277 Thu, 27 Jan 2011 23:58:48 +0100 4405277 http://www.medworm.com/index.php?rid=4371237&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2011.01873.x AbstractIn some biparental mammals, paternal care is important for offspring development and survival. We investigated the influence of the early post‐natal environment on the development of paternal care in the naturally paternal desert‐dwelling African striped mouse (Rhabdomys pumilio). Our aim was to establish whether the expression of paternal care in adult sons is influenced by their experience of paternal care. Offspring were raised in one of three conditions: both parents raised young; mothers raised young alone; and mothers raised young alone but were separated from the father with a barrier. The paternal care behaviour of sons was investigated when they were adults. Contrary to expectations, adult sons raised by the mother alone displayed greater levels of huddling behaviour o... Ethology journals http://www.medworm.com/rss/comments.php?id=4371237 Wed, 19 Jan 2011 23:59:39 +0100 4371237 http://www.medworm.com/index.php?rid=4360553&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2010.01872.x AbstractThere is a wealth of game theoretical approaches to the evolution and maintenance of cooperation between unrelated individuals and accumulating empirical tests of these models. This contrasts strongly with our lack of knowledge on proximate causes of cooperative behaviour. Marine cleaning mutualism has been used as a model system to address functional aspects of conflict resolution: client reef fish benefit from cleaning interactions through parasite removal, but cleaner fish Labroides dimidiatus prefer client mucus. Hence, feeding against their preference represents cooperative behaviour in cleaners. Cleaners regularly cheat non‐predatory clients while they rarely cheat predatory clients. Here, we asked how precisely cleaners can adjust service quality from one interaction to th... Ethology journals http://www.medworm.com/rss/comments.php?id=4360553 Tue, 18 Jan 2011 21:43:16 +0100 4360553 http://www.medworm.com/index.php?rid=4360554&cid=s_38726_98_f&fid=38726&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1439-0310.2010.01870.x AbstractCurrent work in behavioral ecology contrasts traditional hypotheses of context‐specific adaptation with the suggestion that behaviors are often coupled such that animals exhibit context‐general behavioral syndromes. Wasteful killing, the partial consumption and/or abandonment of prey, is a perplexing phenomenon because the costs of this behavior seem high (e.g. energetic loss, risk of injury). Wasteful killing may be the product of a context‐specific, adaptive foraging strategy restricted spatially and/or temporally to conditions of prey abundance. Alternatively, wasteful killing may represent a context‐general syndrome of high aggression that results in the capture of prey that are not consumed. We investigated the conditions in which a web‐building spider the North Amer... Ethology journals http://www.medworm.com/rss/comments.php?id=4360554 Mon, 17 Jan 2011 00:00:00 +0100 4360554