Prior, Nora H.Yap, Kang NianLiu, Tian Qi D.Vignal, Clementine...
155-164页
查看更多>>摘要：Monogamous pair bonds can be transient or long-lasting, which varies across species. The neuroendocrine mechanisms regulating pair maintenance behaviours are largely unknown, yet fundamental to our understanding of monogamy. Furthermore, the expression and regulation of pair maintenance behaviour is likely to be greatly influenced by social and environmental contexts. Our previous research suggested that androgens might regulate long-term pair maintenance behaviour in the monogamous zebra finch, Taeniopygia guttata. Here, we tested the hypothesis that testosterone treatment to males affects long-term pair maintenance behaviour in zebra finches. Established pairs were randomly assigned to one of two groups: control (N = 8) or testosterone (N = 7). Males were given either an empty or a testosterone-filled Silastic implant. Physical and acoustic affiliative behaviours and plasma testosterone levels were examined at three time points: pre-implantation, 30 days post-implant and 60 days post-implant. Importantly, we examined affiliative behaviours under two contexts: in the home cage (baseline) and following a brief chase (post stressor). Male testosterone treatment had no effects on behaviour during the baseline period, but significantly affected behaviours during the post stressor period. Specifically, testosterone-treated males spent less time in close proximity to their partner and sang more. To our knowledge, this is the first report of a context-dependent effect in the neuroendocrine regulation of pair maintenance behaviour, as well as the first report of an inhibitory effect of testosterone on zebra finch pairing behaviours. These results raise interesting questions about the function of affiliative behaviours in established pair bonds. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：In Lepidoptera, male investment in the ejaculate usually declines over consecutive matings, a depletion that could have profound consequences for female reproductive output. Since successive matings can affect the ability of males to provide phenotypic benefits, there may be strong selection for females to discriminate between males with different mating experience. The aim of our study was to determine whether monandrous females of the European grapevine moth, Lobesia botrana, are able to discriminate between males of different quality based on their mating experience in order to maximize direct benefits (by receiving large spermatophores from virgin males) and minimize mating costs (by avoiding low-quality nonvirgin males). Nonvirgin males produced spermatophores five times smaller than those of virgin males; consequently, mating with nonvirgin males significantly reduced female fecundity and increased their motivation to remate. In a mate preference experiment, we found that females were more likely to mate with virgin males and more frequently rejected nonvirgin mates. Moreover, nonvirgin males required more time to achieve mating than virgin males. Our results suggest that females are able to discriminate between males with different mating experience, and prefer virgin males, thereby maximizing direct benefits associated with receiving large spermatophores. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The ability to differentiate between one's own and foreign offspring ensures the exclusive allocation of costly parental care to only related progeny. The selective pressure to evolve offspring discrimination strategies is largely shaped by the likelihood and costs of offspring confusion. We hypothesize that males and females with different reproductive and spatial behaviours face different risks of confusing their own with others' offspring, and this should favour differential offspring discrimination strategies in the two sexes. In the brilliant-thighed poison frog, Allobates femoralis, males and females are highly polygamous, terrestrial clutches are laid in male territories and females abandon the clutch after oviposition. We investigated whether males and females differentiate between their own offspring and unrelated young, whether they use direct or indirect cues and whether the concurrent presence of their own clutch is essential to elicit parental behaviours. Males transported tadpoles regardless of location or parentage, but to a lesser extent in the absence of their own clutch. Females discriminated between clutches based on exact location and transported tadpoles only in the presence of their own clutch. This sex-specific selectivity of males and females during parental care reflects the differences in their respective costs of offspring confusion, resulting from differences in their spatial and reproductive behaviours. (C) 2016 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd.
查看更多>>摘要：In species with alternative reproductive tactics, territorial males (guarders) are usually vigilant against sneakers, and aggressively attempt to eliminate them, imposing serious costs (injuries, sometimes death). Here I examined how sneakers escape from territorial attack in the triplefin blenny, Enneapterygius etheostoma, in the field, with the help of economic flight theory developed for predator-prey interactions. Sneakers hide around spawning sites for sneaking, but they are often detected and attacked by territorial males. Fleeing soon after the initiation of attack could reduce the risk of injuries. However, fleeing may be the wrong decision, resulting in a loss of benefit that could have been obtained by not fleeing, because of uncertainty about whether the sneaker is targeted. As the guarder-sneaker distance decreases, the target would become clear, and uncertainty is reduced accordingly. Therefore, it is predicted that flight initiation distance (FID, the predator-prey distance when escape begins) is determined by the cost-benefit balance. Two types of territorial aggression were identified: the 'direct approach', where the territorial male directly approaches a given sneaker, and the 'reoriented approach', where the territorial male turns to reorient and approaches it following an attack against the first target. A field study showed that sneakers fled earlier in the reoriented approach than in the direct approach. Model selection showed that FID in the reoriented approach was predicted by the guarder-sneaker distance at attack initiation (starting distance) alone, whereas FID in the direct approach was predicted by starting distance, the interaction between the approach speed of territorial males and the duration for which the sneakers monitored them. These results suggest that sneakers adjust flight decision rules to attack episodes, i.e. the economic decision in the direct approach, but the flush early decision in the reoriented approach. This study provides a novel example of adaptation in sneakers. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Rates of innovative foraging behaviours and success on problem-solving tasks are often used to assay differences in cognition, both within and across species. Yet the cognitive features of some problem-solving tasks can be unclear. As such, explanations that attribute cognitive mechanisms to individual variation in problem-solving performance have revealed conflicting results. We investigated individual consistency in problem-solving performances in captive-reared pheasant chicks, Phasianus colchicus, and addressed whether success depends on cognitive processes, such as trial-and-error associative learning, or whether performances may be driven solely via noncognitive motivational mechanisms, revealed through subjects' willingness to approach, engage with and persist in their interactions with an apparatus, or via physiological traits such as body condition. While subjects' participation and success were consistent within the same problems and across similar tasks, their performances were inconsistent across different types of task. Moreover, subjects' latencies to approach each test apparatus and their attempts to access the reward were not repeatable across trials. Successful individuals did not improve their performances with experience, nor were they consistent in their techniques in repeated presentations of a task. However, individuals that were highly motivated to enter the experimental chamber were more likely to participate. Successful individuals were also faster to approach each test apparatus and more persistent in their attempts to solve the tasks than unsuccessful individuals. Our findings therefore suggest that individual differences in problem-solving success can arise from inherent motivational differences alone and hence be achieved without inferring more complex cognitive processes. (C) 2016 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd.
查看更多>>摘要：In many Lepidoptera species usually only males puddle for sodium. Two explanations have been offered for this: (1) neuromuscular activity: males need increased sodium for flight because they are more active flyers than females; and (2) direct benefits: sodium is a type of direct benefit provided by males to females via ejaculate during mating. Surprisingly, there is little direct experimental evidence for either of these. In this study, we examined both explanations using the pipevine swallowtail butterfly, Battus philenor L. If sodium increases neuromuscular activity, males consuming sodium should be better fliers than males without sodium. If males collect sodium for nuptial gifts that benefit their mates, males consuming sodium may have greater mating success than males without sodium. In that case, females then need an honest cue/signal of the quality of male-provided direct benefits that they can assess before mating. If sodium affects male courtship flight by increasing neuromuscular activity, how a male courts could serve as such a premating cue/signal of male benefit quality. Therefore, sodium may benefit males in terms of obtaining mates by increasing their neuromuscular activity. In this study we found that males that consumed sodium courted more vigorously and had greater mating success than males that consumed water. In addition, the courtship displays of males consuming sodium were significantly different from those of males consuming water, providing a possible honest cue/signal of male benefit quality that females can assess. Interestingly, we did not find evidence that sodium consumption affects male flight outside of courtship. That only aspects of male flight related to mating were affected by sodium, while aspects of general flight were not, is consistent with the idea that sodium may benefit males in terms of obtaining mates via effects on neuromuscular activity. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Keiser, Carl N.Wright, Colin M.Pruitt, Jonathan N.
211-218页
查看更多>>摘要：In many societies certain individuals play a central role in the execution of collective behaviours and group success, termed 'keystone individuals'. To date, most studies on keystone individuals have focused on their mere presence/absence and have failed to consider how their influence changes as a function of their condition or recent experiences. Here we explore how the influence of putative keystone individuals on group collective behaviour changes as a function of recent increases in cuticular bacterial load. In the spider Stegodyphus dumicola, individuals that exhibit the greatest 'boldness' are important determinants of colony foraging behaviour and success. We topically exposed individual spiders that varied in their boldness to a combination of naturally occurring cuticular bacteria (Bacillus thuringiensis, Microbacterium oxydans, Pantoea sp.) known to be harmful to S. dumicola, and then tracked the effects that this exposure had on their colonies' foraging and web-building behaviour. We found that colonies with unexposed keystones attacked prey more quickly and with more attackers than colonies in which the keystone was exposed to bacteria. Moreover, the relationship between keystone individuals' boldness and colonies' attack speed differed based on whether or not the keystone was recently exposed. The number of spiders that participated in nightly web building was greater in colonies containing unexposed keystones than in colonies lacking a keystone, whereas colonies containing recently exposed keystones deployed an intermediate number of individuals. This trend, however, disappeared after the second night of observation. Together, our results suggest that a group's collective behaviour can be altered based on a single individual's recent experience with microbes. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Wilson, David R.Ratcliffe, Laurene M.Mennill, Daniel J.
219-229页
查看更多>>摘要：Many animals produce sounds that overlap the sounds of others. In some animals, overlapping is thought to be an aggressive signal important in resource defence. Yet, overlapping can also occur by chance, and therefore its function is controversial. In this study, we conducted two experiments to test the function of overlapping in black-capped chickadees, Poecile atricapillus. In experiment 1, we simulated territorial intrusions by broadcasting songs inside established chickadee territories. Resident males overlapped the playback-simulated intruders significantly less than expected by chance, as in most species in which overlapping has been described. Chickadees also overlapped more when they were farther from the intruder. This pattern suggests that chickadees avoid overlapping as a mechanism for reducing acoustic interference ('interference avoidance hypothesis'). However, the pattern could also constitute submissive signalling if chickadees signal de-escalation (associated with greater distance between opponents) through increasing rates of overlapping ('submissive signalling hypothesis'). Therefore, in experiment 2, we contrasted these two hypotheses by comparing responses to playback stimuli with low or high interference potential and low or high signal value. We manipulated interference potential by broadcasting stimuli at different amplitudes. We manipulated signal value by broadcasting either song stimuli, which elicit aggression, or white noise stimuli with matching time-amplitude characteristics. If overlapping is a submissive signal, then we predicted that chickadees would avoid overlapping song stimuli, but not white noise stimuli, which lack signal value. Contrary to this prediction, chickadees overlapped song and white noise stimuli equally often, but significantly less often than expected by chance. Furthermore, chickadees overlapped both types of stimuli more often when they were broadcast at lower amplitudes (i.e. lower interference potential). Together, these findings provide compelling evidence that overlapping is not a signal in this species, and that chickadees avoid overlapping both biotic and abiotic sounds as a mechanism for reducing interference. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Badescu, IuliaWikberg, Eva C.MacDonald, Lisa J.Fox, Stephanie A....
231-239页
查看更多>>摘要：The rate at which infants develop can vary within species. This variation may be due to differences between infants in their nutritional intake and physiology, or the ability of females to adjust the amount and timing of maternal investment to maximize their lifetime reproductive success. This is the first primate study that uses a large sample size and multivariate analyses to investigate whether variation in early infant development (measured visually using durations of natal coat stages) is explained by differences in infanticide pressure, predation pressure or feeding competition among mothers. We recorded the number of days that infants took to transition through each of the two natal coat stages (white to grey: N = 32; grey to black-and-white: N = 22), as well as through their entire natal coats (white to black-and-white: N = 38) in a population of wild ursine colobus, Colobus vellerosus. Infant males, which are at greater risk of infanticidal attacks, transitioned coat colours earlier than females, and infants in multimale groups, where infanticide occurs more frequently, transitioned earlier than infants in unimale groups. Variation in group size did not affect natal coat durations, which suggests that the intensity of predation risk and feeding competition do not influence development. Instead of terminating investment in offspring before birth, as in the 'Bruce effect', females may invest more heavily in infants after birth in order to speed up infant development and reduce the time period during which offspring are the most vulnerable to infanticide. Mothers may therefore have flexible means of exerting choice over maternal investment in relation to infanticide risk. However, the extent to which mothers and infants are responsible for adjusting the speed of development is unknown. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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