查看更多>>摘要：The songs of many songbird species vary geographically, yet, the songs of black-capped chickadees, Poecile atricapillus, show remarkable consistency across most of the species' North American range. Previous research has described subtle variations in the song of this species by comparing songs produced by males at distant parts of the species' range (British Columbia and Ontario). In the current study, we used an operant discrimination task to examine whether birds classify the songs produced by males in these two previously studied locations as belonging to distinct open-ended categories. In both experiments, when birds were presented with new songs, they continued to respond to songs from the same geographical location as the songs that were reinforced during initial discrimination training, suggesting that birds were using open-ended categorization. We also presented birds with songs in which we manipulated acoustic features in order to examine the acoustic mechanisms used during discrimination; results provide support that birds use the duration of the song when discriminating, but the results also suggest that birds used additional acoustic features. Taken together, these experiments show that black-capped chickadees classify songs into open-ended, geography-based categories, and provide compelling evidence that perceptible acoustic differences exist in a vocalization that is seemingly consistent across the species' range. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Cattelan, SilviaEvans, Jonathan P.Pilastro, AndreaGasparini, Clelia...
105-110页
查看更多>>摘要：Theory predicts that in polyandrous species males that invest more in traits enhancing postcopulatory success should have less energy to invest in mating acquisition, leading to trade-offs between pre- and post-copulatory episodes of sexual selection. Although such trade-offs are well studied, the potential constraints that postcopulatory sexual selection imposes on alternative mating tactics are rarely considered. In guppies, Poecilia reticulata, individual males can obtain matings by performing energetically costly courtship displays or by using less costly forced copulations. In this study we manipulated a component of social environment (namely, the presence of females) to experimentally elevate sperm production in males. We found that male guppies rapidly compensated by reducing their reliance on courtship in favour of forced matings. As both tactics differ in mating and fertilization success, the consequences of this trade-off may have important ramifications for male reproductive fitness. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Direct benefits provided by males have large effects on the fitness of females and their offspring in many species. Here, we examined whether mating or feeding experience of male Carolina sphinx moths, Manduca sexta (Sphingidae), affects the quality of direct benefits that males provide to their mates. We mated virgin females with fed and unfed, virgin and previously mated males. Feeding experience affected male mating success, spermatophore size and flight muscle size. In addition, females mated to fed males laid more eggs than females mated to unfed males, and females mated to virgin males laid more eggs than females mated to previously mated males. Using C-13-enriched glucose in the nectar of the fed males, we found that the second and third spermatophores of males were strongly labelled, but this labelled glucose was not present either in the female's fat body or in her eggs. Therefore, although fed males provided females direct benefits from the sugar in the nectar, the sugar was not used as a nutrient by females. We suggest that in short-lived species, where females mate singly and males mate multiply, and where nectar availability is highly variable, males may be selected to conserve their resources to maintain flight capability and to invest in sperm performance and, thus, provide only limited (non-nutritive) direct fitness benefits to their mates. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Research over the past two decades suggests that polyandry is almost ubiquitous in nature. In some cases, females can gain direct and indirect (genetic) fitness benefits from mating with multiple males. However, when females accept superfluous matings without gaining any clear benefit, polyandry has been interpreted as a strategy to mitigate the costs of resisting or avoiding matings, a situation known as convenience polyandry. When females mate out of 'convenience' the mating rate is expected to be plastic, since females should mate at a higher rate when the costs of resistance or avoidance are high, for instance when males occur in high densities and/or around resources required by females such as oviposition sites. Here we show that remating in Nasonia vitripennis, a species of wasp that is largely monandrous in the wild but that evolves polyandry under laboratory culture, is dependent upon the availability of hosts for oviposition and upon male density. We found that females mated at a higher rate when male density was high but only if a suitable oviposition substrate was available. Outwardly this seems suggestive of convenience polyandry. However, females that remated under these conditions did not gain more time to oviposit than females that resisted superfluous matings. The results of this study highlight the importance of comprehensively assessing the costs and benefits of mating before attributing the observed behaviour to convenience polyandry. Furthermore, these results add to the growing body of evidence that the ecological context under which sexual interactions occur is critical to the economics of mating. (C) 2015 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd. This is an open access article under the CC BY license
Foo, DahliaSemmens, Jayson M.Arnould, John P. Y.Dorville, Nicole...
127-138页
查看更多>>摘要：Empirical testing of optimal foraging models on diving air-breathing animals is limited due to difficulties in quantifying the prey field through direct observations. Here we used accelerometers to detect rapid head movements during prey encounter events (PEE) of free-ranging benthic-divers, Australian fur seals, Arctocephalus pusillus doriferus. PEE signals from accelerometer data were validated by simultaneous video data. We then used PEES as a measure of patch quality to test several optimal foraging model predictions. Seals had longer bottom durations in unfruitful dives (no PEE) than those with some foraging success (PEE >= 1). However, when examined in greater detail, seals had longer bottom durations in dives with more PEES, but shorter bottom durations in bouts (sequences of dives) with more PEES. Our results suggest that seals were generally maximizing bottom durations in all foraging dives, characteristic of benthic divers. However, successful foraging dives might be more energetically costly (e.g. digestive costs), thus resulting in shorter bottom durations at the larger scale of bouts. Our study provides a case study of how the foraging behaviour of a central place forager foraging in a fairly homogeneous environment, with relatively high travel costs, may deviate from current foraging models under different situations. Future foraging models should aim to integrate other aspects (e.g. diet) of the foraging process for more accurate predictions. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Jolles, Jolle WolterTaylor, Benjamin AaronManica, Andrea
139-145页
查看更多>>摘要：Animal personalities are ubiquitous across the animal kingdom and have been shown both to influence individual behaviour in the social context and to be affected by it. However, little attention has been paid to possible carryover effects of social conditions on personality expression, especially when individuals are alone. Here we investigated how the recent social context affected the boldness and repeatability of three-spined sticklebacks, Gasterosteus aculeatus, during individual assays. We housed fish either solitarily, solitarily part of the time or socially in groups of four, and subjected them twice to a risk-taking task. The social conditions had a large effect on boldness repeatability, with fish housed solitarily before the trials showing much higher behavioural repeatability than fish housed socially, for which repeatability was not significant. Social conditions also had a temporal effect on the boldness of the fish, with only fish housed solitarily taking more risks during the first than the second trial. These results show that recent social conditions can thus affect the short-term repeatability of behaviour and obfuscate the expression of personality even in later contexts when individuals are alone. This finding highlights the need to consider social housing conditions when designing personality studies and emphasizes the important link between animal personality and the social context by showing the potential role of social carryover effects. (C) 2015 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd. This is an open access article under the CC BY license
查看更多>>摘要：I experimentally tested the repeatability and plasticity of two antipredator behaviours, shoaling and risk taking, in a sample of 443 juvenile three-spined sticklebacks, Gasterosteus aculeatus. I quantified between-individual variation in these behaviours as well as behavioural changes over time in two groups of sticklebacks that were either exposed or not exposed to simulated predation pressure. Shoaling and risk taking were repeatable within individuals in both experimental and control fish. Individual willingness to shoal increased over time in both experimental and control groups, but there was no evidence that shoaling changed in response to predation risk. Risk taking also showed temporal changes: sticklebacks exposed to simulated predation risk became increasingly fearful, unlike the control fish, suggesting that this behaviour is plastic. There was, however, no evidence of between-individual variation in the behavioural changes over time in either the control or experimental condition, suggesting that behavioural plasticity is a fixed response in the individuals of this population. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Colonial species breed in densely aggregated territories containing no resources other than nest sites. This behaviour is usually explained by natural selection, for instance through benefits resulting from reduced predation risk. An alternative hypothesis suggests that, as in lek breeding systems, sexual selection may be responsible for the aggregation of competitors, driven by an increased potential for female mate choice among closely assembled males. Lamprologus callipterus, a shell-brooding cichlid fish of Lake Tanganyika, provides an ideal test case for the utility of lek evolution models to explain colonial breeding, because breeding territories are established by males before pairing. Large males collect and defend empty snail shells that are then chosen by females for breeding. We checked for a potential influence of sexual selection on colonial breeding in L callipterus by testing predictions of the hot-shot and female preference hypotheses of lek mating models. In the field, we found that territories of larger males were more centrally located and that females preferred to breed with males surrounded by many neighbours, two findings that are consistent with lek mating models. Female preference suggests that sexual selection affects colonial breeding in L callipterus, which implies an influence of sexual selection on the evolution of colonial breeding at large. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Ejaculate production can be costly and males are expected to prudently allocate this potentially limiting resource to higher quality females. However, relatively little is known about facultative sperm allocation in response to the quality distribution of sequentially encountered females, despite this being a more realistic scenario for males in many species. Here, we examined patterns of male investment in a squid, Sepiadarium austrinum, when presented sequentially with small versus large females. Owing to a positive size - fecundity relationship in this species, large and small females are expected to differ in terms of their perceived quality to males as potential mating partners. Yet, despite large sperm investment and significant variation in female quality, sperm investment was determined only by mating order, with males consistently decreasing sperm investment in second matings. These results highlight that, when mates are encountered sequentially rather than simultaneously, prudent sperm allocation may not occur when it is otherwise predicted. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The use of cuticular hydrocarbons (CHCs) in species recognition, sex identification and sexual selection is widespread in insects. However, few studies have studied plasticity in CHCs. Here we examine the effect of age and social environment on a suite of sexually selected CHCs in Drosophila serrata. We demonstrate that the combination of CHCs that is associated with increased male mating success (CHC beta changes as males age, and this effect is mediated by social environment. When single males were housed with multiple females, their expression of CHC beta increased across the first few days of their adult life, after which expression declined with increasing age. In contrast, sexually selected CHCs of males housed with other males, males housed with other males and females, and males housed alone all decreased across days. To determine the long-term consequences of mating on CHC expression, we allowed males a single mating opportunity and subsequently found some indication of a brief spike in CHC beta. Finally, to determine whether visual and olfactory contact with females, copulation, or intromission causes males to express high values of CHC beta, we manipulated male access and physical contact with females. We found that although prolonged copulation causes a slight increase in male CHC beta, only a successful copulation with sperm transfer induced males to develop CHCs associated with high mating success. Taken as a whole, our results demonstrate that the expression of sexually selected CHCs in males varies with both age and social context, and suggest that the latter is mediated at least in part by successful matings with females. More generally, contextual plasticity in CHCs is likely to affect both the experimental design of CHC-based experiments and the evolution of CHC signals as naturally and sexually selected traits. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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