查看更多>>摘要：Courtship signalling, necessary for the recognition of potential mates, is often complex, using many modalities with multiple components. Drosophila courtship comprises chemical, tactile, visual and acoustic stimuli. Ablation of single sensory channels, either signal production or reception, can determine the roles of individual modalities in overall reproductive success. Adding measures of courtship timing, particularly courtship latency, the time for the male to initiate courtship, and courtship duration, the time from courtship initiation until the female accepts the male for copulation, allows us to identify the stage of courtship at which a signal acts. This study focuses on Drosophila saltans, a member of the saltans species group. Little is known about sexual behaviour of species in this group, part of the Sophophora subgenus. In the present study, we found that ablation of any one signal in D. saltans did not eliminate mating, thus courtship is multimodal. In addition to examining the signals and signal reception common to most Drosophila species, we also examined the role that the midtarsi play in courtship. The removal of the female's midtarsi significantly reduced mating occurrence. Using timing data, we discerned that the absence of midtarsi in the female did not affect the male's ability to identify the female as a potential mate, but the male may be unable to sufficiently stimulate the female to copulation. Measuring courtship latency and courtship duration, as well as the occurrence of courtship and copulation, allowed us to determine whether a particular signal plays a role in activating the male to initiate courtship or stimulating the female to mate. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Barocas, AdiGolden, Howard N.Harrington, Michael W.McDonald, David B....
103-114页
查看更多>>摘要：Fissione-fusion dynamics, consisting of regular shifts in the size and composition of social groups, are prevalent in animal societies and have implications for foraging success, disease and information transfer, and the fitness of individuals. Thus, the individual and environmental factors that drive social dynamics have become a focus of recent investigations. River otters, Lontra canadensis, in coastal Alaska have a plastic social system, influenced by forage fish availability. These carnivores also regularly frequent terrestrial latrine sites, where they associate and communicate through deposition of odorous substances. To investigate fissione-fusion dynamics in this system we (1) deployed camera traps to record social behaviours at latrine sites and (2) attached proximity tags to quantify encounter rates among individuals. Camera detections demonstrated that most latrine visits were of single otters and small groups (2-8 individuals). Fusion events into large groups (up to 18 individuals) were infrequent. Larger groups were recorded at crossover latrines, where trails connected bodies of water, whereas social behaviour was more frequent at spatially central latrines. Visiting otters performed signalling behaviours more frequently than social behaviours, especially at crossover sites. Proximity tag data revealed that the timing of fission and fusion events coincided with latrine visits and that spatial overlap was a good predictor of social interaction. Thus, the structural and spatial features of latrines influence their function as centres of information exchange, social activity hubs and meeting places among small social units, with implications for river otter group dynamics. We conclude that shifting social and environmental conditions may lead to high communication complexity. This unique social system provides novel evidence of the role of olfactory communication in mediating social decisions. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Complex behaviour may incur a cost. We assumed here that web-building behaviour for two species of orb-web spider, Cyclosa argenteoalba and Eriophora sagana, was more complex when their webs were asymmetric from top to bottom than when their webs were symmetric. The rationale for this assumption was that, while spiders have to adjust their spiral building behaviour in different web sectors to build asymmetric webs, they do not have to make these adjustments for symmetric webs. To estimate the costs involved in building more asymmetric webs, we measured the time taken for spiders to build orb-webs with various up-down size asymmetries and used this as a measure of the complexity of web-building behaviour. The results showed that the spiders required more time to lay the spiral threads as their webs became more asymmetric even when the length of spiral threads was the same, suggesting a time cost of processing complex information. Furthermore, we found that spiders built more symmetric webs when they perceived a risk of predation, perhaps to reduce the web-building time during which they are more vulnerable. This suggests that the cost of behavioural complexity may mediate the outcome of interspecific interactions and thus may be ecologically important. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Wolfe, Kevin D.Wainwright, Marcy L.Smee, Delbert L.Mozzachiodi, Riccardo...
123-133页
查看更多>>摘要：Prey often modify their behaviours to diminish predation risk, but the persistence of such behavioural changes are not well understood. We investigated the effects of predation risk in the aquatic mollusc Aplysia californica to determine whether various natural aversive stimuli alter the expression of feeding behaviour (i.e. bites) over short-term (15 min), intermediate-term (2 h) and long-term (24 h) periods. Aplysia were presented with a variety of natural aversive stimuli that are indicative of predation risk, including exposure to the spiny lobster Panulirus interruptus (a natural predator), the blue crab Callinectes sapidus (a novel predator), and the defensive secretions ink and opaline that are normally released by Aplysia when attacked. Feeding was significantly suppressed immediately after Aplysia were exposed to ink but not to opaline. Additionally, several stimuli, including exposure to lobsters, ink, opaline and attacks from crabs, suppressed feeding, but only for a short time (i. e. 15 min) after the end of the stimulus. No single-exposure treatment elicited intermediate (2 h) or long-term (24 h) changes in feeding, and multiple exposures to ink did not induce long-term feeding suppression. Thus, changes in feeding behaviour in response to predation risk cues appear short-lived in Aplysia, unlike feeding suppression after electric shocks that suppress biting behaviour over longer periods. Since Aplysia possess chemical defences to defend against consumers, it is perhaps unnecessary or too costly to maintain feeding suppression after risk subsides. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Hunter, Elizabeth A.Nibbelink, Nathan P.Cooper, Robert J.
135-142页
查看更多>>摘要：Habitat selection trade-offs between avoiding predation and gaining energy are well studied, but similar trade-offs resulting from multiple threats to survival remain poorly understood. We studied how seaside sparrows, Ammodramus maritimus, approach nest site selection decisions to avoid threats to nesting success from predation and tidal flooding. Along a nest height gradient, nest site selection to avoid tidal flooding (i.e. placing nests higher) may make seaside sparrow nests more vulnerable to predation, and selection to avoid predation may make nests susceptible to flooding. We monitored nesting success rates and nest site selection decisions of breeding seaside sparrow pairs at five sites near Brunswick, Georgia in April-July of 2013-2015. We found that seaside sparrows encountered a nest site selection trade-off along a gradient of nest height. Nest height had an effect on survival probability during each of our study years, with positive effects of nest height on predation probability and negative effects of nest height on flooding probability observed in some years. Sparrows dealt with this trade-off by altering their nest site selection in relation to a threat's predictability; low within-season variability in predation risk and high information about predator presence in open marshes make predation risk more predictable than the magnitude of tidal flooding, which is governed by unpredictable and variable winds. Sparrows responded to predictable predation threats by nesting at lower nest heights in years with higher predation risk, but sparrows responded to unpredictable flooding threats by placing nests higher off the ground but only following nest failure from flooding. Understanding decision making through a lens of threat predictability could provide a useful approach for studies of other animals' habitat selection trade-offs. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Previous studies have shown that domestic chicks, Gallus gallus domesticus, trained in a competitive foraging condition would subsequently develop a high degree of impulsiveness in an intertemporal choice paradigm. Competition inevitably causes variance in the amount of food that the foragers gain. However, it is not known whether the food variance is causally linked with the impulsiveness. In experiment 1, we compared four groups of chicks trained in combinations of two social conditions (pseudocompetition or isolated) and two food conditions (variable or constant food). The food variance was introduced by varying the number of grains in each trial according to a binomial distribution. The subject chick was separated from the competitors by a transparent wall, and no actual interference occurred. Chicks were subsequently tested in binary choices between a small reward after a short delay (SS) and a large reward after a long delay (LL) in an isolated and constant food condition. If chicks had been trained under the pseudocompetition and variable food, they chose LL significantly less frequently than the other three groups. The effect disappeared when the LL delay was omitted, suggesting that chicks accurately memorized the food amount. The food variance is thus a necessary condition for the stronger temporal discounting. Otherwise, the observed effect could be ascribed to a paradoxical risk proneness associated with the variable option. In experiment 2, we compared four groups of chicks in which food amount varied either in SS or LL, or both. The subsequent binary choice tests revealed that the chicks chose SS irrespective of whether SS or LL had varied. These results cannot be explained in terms of a greater risk-prone choice of the variable option. Coincidence of perceived competition and food variance, at least in one option, is sufficient for chicks to develop choice impulsiveness. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Ingley, Spencer J.Pruitt, Jonathan N.Scharf, InonPurcell, Jessica...
153-161页
查看更多>>摘要：Immigrant viability is a major determinant of the realized rate of gene flow across populations. For social organisms, the social context in which immigrants disperse across contrasting environments may have important implications for their viability post dispersal. Here, we use social spiders whose individual personalities as well as group personality compositions vary across sites to test whether the strength of selection against immigrants (i.e. mortality rates) differs depending on whether spiders are transplanted (1) as individuals and remain alone, (2) join pre-existing colonies at their new non-native environment, or (3) move with their native group. We also tested for an effect of individual personality on survival. We found that social context, and not individual personality, affects individual survival in foreign environments with contrasting resource levels. Individuals that were transplanted with their native groups suffered higher mortality rates compared to individuals transplanted as singletons, regardless of whether or not they were assimilated into native colonies. Moving as individuals could thus provide an avenue for ongoing gene flow among populations from different resource environments. We found no depressed performance of control colonies that were transplanted across sites with resource levels similar to each colony's site of origin. These results are at odds with the intuition that dispersing as a group should generally enhance the viability of immigrants, at least in social species. We propose that these results could be explained by a mismatch in the ideal group compositions (personality compositions) favoured in different environments, despite a lack of selection on individual personality traits. These results provide a first glimpse into the relative roles of individual personality and social context in mediating gene flow among populations from divergent environments. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Learned song is among the best-studied models of animal communication. In oscine songbirds, where learned song is most prevalent, it is used primarily for intrasexual selection and mate attraction. Learning of a different class of vocal signals, known as contact calls, is found in a diverse array of species, where they are used to mediate social interactions among individuals. We argue that call learning provides a taxonomically rich system for studying testable hypotheses for the evolutionary origins of vocal learning. We describe and critically evaluate four nonmutually exclusive hypotheses for the origin and current function of vocal learning of calls, which propose that call learning (1) improves auditory detection and recognition, (2) signals local knowledge, (3) signals group membership, or (4) allows for the encoding of more complex social information. We propose approaches to testing these four hypotheses but emphasize that all of them share the idea that social living, not sexual selection, is a central driver of vocal learning. Finally, we identify future areas for research on call learning that could provide new perspectives on the origins and mechanisms of vocal learning in both animals and humans. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：During sexual selection members of the opposite sex utilize a variety of signal modalities to acquire information about potential mates. As a prerequisite, signal modalities must exhibit intraspecific variation and correlate with desirable traits that reflect the fitness of the signaller. Anecdotal accounts suggest that female psyllids (Hemiptera: Sternorrhyncha) utilize substrate-borne vibrations (SBVs) to choose between males. However, comprehensive studies investigating the role of SBVs in Psylloidea are lacking. We used laser vibrometry and playback experiments to study the mating and calling behaviours of a psyllid, Aacanthocnema dobsoni (Triozidae). Specifically, we quantified call parameters and asked whether they vary intraspecifically and correlate with male body size and age. We also tested whether female responsiveness is influenced by the body size and age of calling males. Calls were sex-specific: male calls were more complex and comprised long and short syllables while female calls comprised only short syllables. Temporal and spectral parameters of male calls differed significantly from those of female calls. Calls of both sexes exhibited a high level of intraspecific variation. Larger males produced calls with a lower dominant frequency and older males produced calls of higher intensity and pulse rate. We used playback to test female responsiveness to calls recorded from males of contrasting sizes and ages. Surprisingly, female responsiveness was not influenced by body size or the age of calling males. Interestingly, females are polyandrous but only virgins called or responded to male calls. Conversely, males called frequently and attempted (and often succeeded) to mate with unresponsive females. These results demonstrate that A. dobsoni utilizes SBVs for mate attraction but not for precopulatory mate selection. We suggest that polyandry in A. dobsoni potentially evolved in response to male harassment and, as a consequence of polyandry, sexual selection is probably achieved via postcopulatory sexual selection mechanisms. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：A competitive resource-based environment such as larval crowding is an important stress factor in the life history of holometabolous insects such as Drosophila melanogaster and can have major consequences for adult fitness through its direct effects on body size. We investigated precopulatory sexual behaviour, which is an important subset of adult fitness, using D. melanogaster populations adapted to larval crowding for 100+ generations. We found that selected males evolved significantly higher courtship frequency than their ancestral controls. While we found a negative correlation between larval density and adult courtship frequency using low, moderate and high larval rearing densities, we also found that supplementation of live yeast, which is an important dietary component in their life cycle, caused a significant rise in courtship frequency. We further dissected out the male and female behavioural components that contribute to overall courtship activity by factorially combining selected and ancestral male and female types, reared in both low and high larval densities, and found that courtship frequency of selected males was higher with selected females than with control females. We also quantified the mating frequency, a crude measure for mating success, and found that increased courtship frequency in selected populations did not lead to increased mating success. From the results of this and a previous study, we conclude that precopulatory sexual activity in these populations is not traded for life span. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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