查看更多>>摘要：Genetic polymorphism in males has long been considered paradoxical because sexual selection is expected to deplete additive genetic variation. Although studies have shown how divergent selection between populations can make that work, it is very rare to find disruptive selection within one population. Since intersexual selection can have a significant effect on the phenotypic morphospace of the opposite sex, we analysed the role of female preference as a disruptive selective force. In this study we evaluated how female preference acts on anatomical and sex-related behavioural traits of two male morphs in the jumping spider Maevia inclemens. We used mate choice trials to analyse how female preference for the two morphs varied. The tests indicated that females preferred opposite values of two anatomical and two behavioural traits for each male morph. This study is, to our knowledge, the first to show disruptive sexual selection in Arachnidae and significantly expands the realm of disruptive selection, by adding one more case to the very few documented instances. These processes, which act entirely within a species, are of particular interest because they could contribute to the evolution of reproductive isolation and sympatric speciation by sexual selection, a controversial topic in evolutionary biology. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Social learning, learning from others, allows animals to quickly and adaptively adjust to changing environments, but only if social learning provides reliable, useful information in that environment. Early life conditions provide a potential cue to the reliability of social information later in life. Here, we addressed whether direct early life experience of the utility of social learning influences later social learning propensities. We reared guppy, Poecilia reticulata, fry for 45 days in three different social conditions which involved the presence of adult demonstrators providing cues about feeding locations in the tanks ('follow adults' and 'avoid adults' treatments), or their absence ('no adults' treatment). In the 'follow adults' treatment, juveniles that swam in the same direction as the adult demonstrators found food, whereas in the 'avoid adults' treatment, subjects that swam in the opposite direction to the demonstrators found food. We then tested the fish with a social learning task, to examine whether prior experience had influenced the social learning tendencies of the juveniles. After another 45 days of rearing under common-garden conditions with no adult fish present in the tanks, subjects were retested with the same social learning task, to investigate whether early experiences had effects persisting into adulthood. After 45 days of rearing we found no evidence for social learning in any of the experimental groups. However, after 90 days of rearing, we found evidence of social learning, but only in the 'follow adults' treatment. These results suggest that social learning propensities may develop over life, and that prior exposure to conspecifics providing useful foraging information during early life can shape the degree of reliance on social learning in adulthood. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The aim of this study was to determine whether visual recognition of conspecifics exists in zebra finches, and if so, whether the strength of this recognition is a function of the social relationships among flock members. To achieve this aim, we trained adult female zebra finches to indicate their preference by pecking on one of two photographs presented on a digital screen. We found that female zebra finches possessed a very good ability to recognize their mates, and a slightly lower but still good ability to recognize other, socially closely related males that were members of their own small flock. Moreover, we found that the individual integrity of the small flocks continued to be maintained, as subgroups, even after these were combined to form one large flock, indicating that zebra finches demonstrate different levels of social relationships between flock members, and that these relationships are long-lasting and stable. However, when part of a larger flock, the females were unable to recognize males that were socially distant to them. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The mating propensity of an individual is expected to depend on the costs and benefits of mating, which may vary across the sexes and across different mating opportunities. Both males and females should gain fitness either by mating with multiple mates and/or by mating with higher quality mates. Therefore, an important question in the area of sexual selection concerns what makes an optimal mate. From a female perspective, females are expected to prefer males providing direct material benefits for the present generation and/or indirect genetic benefits for their offspring in the subsequent generation. Because the male's contribution to these benefits can be limited, as reproduction imposes nontrivial costs on males, the female's benefits from mating can vary markedly as a function of the condition of her mate. In capital breeding species, in which males invest most of their larval resources in a single reproductive event, the females are likely to prefer to mate with virgin males in good condition (i.e. males that have developed on high-quality food sources). In this study we used the European grapevine moth, Lobesia botrana, to test experimentally whether the larval nutrition and mating history of males influence their quality as mates. We provided wild L. botrana males originating from different cultivars and vineyards with unlimited access to standardized females, and examined the lifetime reproductive success of the males and the consequences for the reproductive output of females. Our results show that 'male quality' depended on both the male larval origin and mating history, and that females discriminated between males and mated more with males having high spermatophore quality (virgin males and males from certain cultivars or vineyards) to obtain substantial direct benefits. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Cristaldo, Paulo F.Rodrigues, Vinicius B.Elliot, Simon L.Araujo, Ana P. A....
43-49页
查看更多>>摘要：Termite inquilines specialize on living in and feeding on a host termite nest. However, the mechanisms allowing survival of two mutually hostile populations confined to a single nest are not understood. Here we report on inquiline termites that respond to their host's alarm cues. Upon detecting these cues, the inquilines do not join in with the host's nest defence, but use this information for their own benefit, to escape danger. Using behavioural bioassays under laboratory conditions, we show that the obligatory inquiline Inquilinitermes microcerus (Termitidae: Termitinae) responds both to its own alarm signal and to alarm cues from its host, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae). Conversely, this host responded only to its own alarm signal. Despite perceiving their host's alarm cues, inquilines were never observed sharing nest defence with their host in experimentally damaged nests in the field. We argue that this allows inquilines not only to minimize encounters and hence conflict with their hosts, but also to use their host alarm information to escape the host's enemies, which are also likely to be enemies of the inquilines. Our results show a new benefit that inquilines gain from the host, and we discuss the inquiline way-of-life from an evolutionary perspective, as the outcome of constraints and benefits imposed by living in host nests. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Salticids are known for their complex predatory behaviour, which is based on the analysis of visual information from their prey, but the role of cues used in different predatory tasks is poorly known. We investigated which cues are used to identify the preferred target on the prey's body, examining the reactions of the euryphagous salticid Yllenus arenarius to various virtual prey presented on a miniature screen. We manipulated the number of head-indicating details (ranging from prey with four details, including a head spot, antennae, legs and wings, to prey lacking any details), the position of these details in relation to motion direction (in the leading versus in the trailing part of the body), the local motion of legs and the presence of horizontal motion. When all cues pointed to the same body end the spiders identified the preferred target almost unerringly regardless of the number of details. Movement alone, movement combined with a different number of details in the leading part, local motion of legs and head spot alone on motionless prey elicited the same reactions. When the cues provided contradictory information (motion direction and details pointing to opposite body ends) the spiders struck the trailing end more often the more details were placed there, and they visually inspected body ends of their prey before attack. These results indicate that the spiders used the direction of the prey's motion and the complexity of head-indicating details when making decisions related to strike targeting. These findings elucidate the role of motion and the complexity of details forming 'false heads', an antipredator adaptation assumed to redirect predatory strikes on prey from various animal groups. We demonstrate that in stationary prey even very simple patterns efficiently redirect predatory strikes. We provide the first experimental evidence of the effectiveness of 'false head' complexity in moving prey. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Johnson, J. ChadwickHalpin, RebeccaStevens, Dale R., II
61-66页
查看更多>>摘要：Cannibalism, intraspecific predation, is a fascinating behaviour that can serve as a model system for researchers interested in learning more about conspecific conflicts ranging from siblicide to sexual cannibalism. Cannibalism is most often studied in terms of the benefits it provides the predator, but the prevalence of such an ecologically significant behaviour is also shaped by the costs inherent in a cannibalistic attack. Perhaps most intuitively, the risk of injury when attacking a conspecific of similar or larger size has been considered, and led to the prediction that cannibalism should be most common by larger individuals among asymmetrically sized pairs. This prediction is commonplace in the cannibalism literature, and leads to the more novel hypothesis that siblicide then may be reduced to the extent that maternal investment yields developmental synchrony and size-matched siblings. Here we test these hypotheses in the western black widow spider, Latrodectus hesperus, by rearing some eggs at 4 degrees C warmer temperatures for 7 days, and thus experimentally creating size asymmetries between clutchmates. Our temperature manipulation was successful at speeding development (eggs reared at warmer temperatures attained their first moult 2.5 days sooner than their counterparts). This developmental asynchrony accelerated cannibalism by more than 3 days relative to control groups in which eggs and spiderlings were all reared at either consistently colder or warmer temperatures. Lastly, the mass and size of an egg were poor predictors of cannibalism in both treatments that included individuals reared at warm temperatures. In contrast, in our control group where both eggs were reared at cooler temperatures, we found that families typified by heavier and larger eggs were slower to show cannibalistic behaviour. We discuss the implications of these findings, paying particular attention to their relevance to the black widow's emerging role as an urban pest. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Londe, SylvainMolet, MathieuFisher, Brian L.Monnin, Thibaud...
67-76页
查看更多>>摘要：Evolutionary novelty can arise through the recombination of ancestral characters. In ants, colonies occasionally produce anomalous individuals that are mosaics of queen and worker characters. These intermediate individuals may be the first step in the evolution of new castes such as wingless queens and soldiers. While the morphological features of intercastes support this hypothesis, their rarity has meant their behaviour is unknown. In this study we carried out a behavioural study of 32 intercastes of Mystrium rogeri to assess whether they are a burden for their colonies, and whether their unusual morphologies are associated with consistent behavioural profiles and new functions. In addition, we measured dominance interactions within colonies, reproductive behaviours during dyadic encounters with males and aggressive interactions during dyadic encounters with heterospecific workers. We found that intercastes were active in colonies and that their behavioural profiles did not differ from those of virgin queens and workers. However, some intercastes were dominant, had developed ovaries and attracted males. One intercaste successfully mated and laid diploid eggs, demonstrating her reproductive potential. Moreover, we found that intercastes were as capable of fighting as workers because of their large size and could thus be useful for colony defence. Our results show that the production of intercastes in M. rogeri inflicts few costs but can yield benefits. Accordingly, certain ecological circumstances could select for increased frequency of intercaste production, ultimately resulting in the evolution of new reproductive and defensive castes. (C) 2016 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
查看更多>>摘要：In social species, groups of individuals that live, forage or interact with each other often form a linear dominance hierarchy. Dominant individuals are thought to have greater access to resources and the ability to obtain higher-quality territories or mates, making dominance rank important to maximizing fitness. Social animals are often susceptible to infections from parasites or pathogens, and the energetic cost of mounting an immune response, along with displaying sickness behaviours, could affect an individual's social relationships. If a dominant individual becomes sick and is made vulnerable to challenges from lower-ranking group members, a loss in rank could be detrimental. Many songbirds, such as the black-capped chickadee, Poecile atricapillus, form seasonal social flocks during the winter, then divide into pairs for breeding during the spring. Our study used captive chickadees to determine whether a challenge to the immune system affects social dominance behaviour and status in the winter flock. In captive experimental flocks, top-ranked individuals were given an immune challenge in the form of a lipopolysaccharide (LPS) injection, and dominance behaviour was observed to determine whether status was altered. LPS-injected individuals lost a significant amount of weight and increased feeding rate when compared to control-injected birds, indicating an energetic cost, but they showed no change in dominance behaviour or loss of rank. These findings suggest that maintaining rank by continuing to invest in dominance behaviours is important in order to retain the fitness benefits associated with a high dominance rank. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Russell, Avery L.Leonard, Anne S.Gillette, Heather D.Papaj, Daniel R....
83-91页
查看更多>>摘要：Pollinators frequently use complex motor routines to find and extract floral rewards. Studies of pollinators foraging for nectar rewards indicate these routines are typically learned, and that constraints associated with learning and memory give pollinators incentive to continue foraging on these flowers. However, plants offer rewards besides nectar, including pollen, lipids and essential oils. In particular, bees use a complex motor routine termed floral sonication to extract pollen, their primary source of protein, from the more than 6% of flowering plant species (>22000 species) that conceal pollen rewards within tube-like poricidal anthers. If floral sonication requires learning, this pollen extraction behaviour could contribute to floral fidelity. However, no studies have quantified the effect of experience on flower handling for bees extracting pollen from poricidal species. We therefore examined the degree to which floral sonication behaviour was modified by experience. We found that the key elements of the sonication motor routine appeared in full-blown form in a flower-naive bee's first visit to a flower. We additionally found consistent, albeit modest, effects of experience on certain aspects of sonication behaviour. The latency to sonicate slightly decreased with experience. Bees also adjusted the length and amplitude of their sonication buzzes in response to pollen receipt. We conclude that the role of experience in foraging for concealed pollen rewards is different from that reported for nectar rewards. We offer an alternative explanation for its function in sonication. Finally, we discuss alternative hypotheses for the function of poricidal anthers and for how pollen-bearing plants may ensure floral fidelity even in the absence of a significant impact of experience on pollen extraction behaviour. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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