查看更多>>摘要：Whether begging behaviour mediates food provisioning has been extensively studied in birds. However, begging behaviour occurs without direct offspring competition in some species and thus may be driven exclusively by intrabrood dynamics. We studied begging behaviour of individually housed offspring of the biparental mimic poison frog Ranitomeya imitator. We tested whether (1) begging is an honest signal of need or hunger, (2) begging is costly and (3) parents allocate food according to offspring need. Under manipulation of long-term diet, food-limited tadpoles increased begging effort over the course of development. Tadpoles that were induced to beg suffered a cost of taking longer to reach developmental stages and showed a marginal cost on growth rate. Finally, parents were more likely to feed the tadpole that was exposed to a nonsupplemented diet over its food-supplemented sibling. In R. imitator, begging behaviour appears to signal offspring need honestly and thus may predict differential food provisioning among offspring. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：In multimale multifemale primate groups, the strength and stability of affiliative relationships have been shown to affect an individual's long-term fitness such as offspring survival and longevity. Studies investigating the fitness benefits of close social relationships and the underlying mechanisms have mainly focused on the philopatric sex. The strong relationships of philopatric chimpanzee males and baboon females share important characteristics with human friendships in that increased strength of affiliative relationships is associated with increased equitability in service exchanges and relationship stability. So far, it has remained unclear whether the strong relationships of dispersing males share these characteristics as well and can thus be labelled as social bonds. Here we provide results on the variation in affiliative relationship strength and its relation to equitability and relationship stability from two wild groups of male Assamese macaques, Macaca assamensis, at Phu Khieo Wildlife Sanctuary, Thailand collected over 2 and 7 years, respectively. Our analyses of almost 9000 h of focal animal data show that males formed differentiated affiliative relationships and that the strength of a relationship affected how likely males returned a grooming service within a single bout and how equally males were responsible for the maintenance of close proximity. Partner stability among the three strongest relationships was higher than among weaker relationships which suggests that top partners were not retained simply because of a lack of alternatives. Together, these results suggest that dispersing male Assamese macaques form differentiated affiliative relationships that increase in equitability and stability with increasing relationship strength. This is the first study showing long-term partner stability in males as the dispersing sex. Our results thus add to the growing body of literature indicating that nonhuman animals form close social relationships similar to human friendships. (C) 2016 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd.
Eddy, Sarah L.Wilburn, Damien B.Chouinard, Adam J.Doty, Kari A....
23-29页
查看更多>>摘要：In many vertebrate mating systems, mate choice evolves when signalling via visual, chemical or auditory traits is an energetically costly process. Selection may favour individuals that can discriminate among potential mates and invest in signalling to mates with particular characteristics. Most commonly, females with costly gametes are thought to be the more selective sex; however, runaway sexual selection can produce elaborate male ornaments and behaviours that are similarly costly to produce, which can lead to male mate choice. In this study, we used behavioural trials to experimentally test male mate choice in a terrestrial salamander, Plethodon shermani. We investigated whether males altered the proportion of time they spent performing a potentially costly courtship display, 'foot dancing', in the presence of females. Specifically, we explored male mate choice in two experiments: (1) measuring how males modified the time they invested in courtship based solely on female reproductive value, and (2) determining whether males varied the amount of time they invested in courting females of varying sizes but similar reproductive value. In the first experiment, we quantified the duration of male courtship displays when males were paired with females of differing levels of fecundity (nongravid, weakly gravid and strongly gravid). Males displayed longest for females of high reproductive value (strongly gravid females) and less for weakly gravid and nongravid females. In the second experiment, we showed that males paired sequentially with different-sized females of similar reproductive values displayed significantly more often to larger females (i.e. male effort positively correlated with female size). In conclusion, male P. shermani are one of the few vertebrates known to modify their display behaviour based on female mate quality, and visual signs, such as size, may provide honest indicators of fitness. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Lopez-Rull, IsabelLifshitz, NataliaMacias Garcia, ConstantinoGraves, Jeff A....
31-38页
查看更多>>摘要：Sexual selection may facilitate speciation if it promotes divergence in attributes used in mate choice, causing prezygotic isolation between populations. Brown boobies, Sula leucogaster, are seabirds that can be grouped into four genetic clusters and two male plumage morphs: brown-headed sexually monomorphic and white-headed male dimorphic. The extent of white on the head (white hood) of a male may reflect parenting ability and be sexually selected. Colour morphs have been geographically isolated, but contact has been recently reported. We manipulated male hood colour in two dimorphic populations (at Islas Marietas National Park (hereafter Marietas), which is close to the contact zone of San Benedicto Island, and San Jorge Island, which is away from the contact zone) to establish whether female preference for male hoods can function as a reproductive barrier. Females from Marietas were more aggressive towards male mates whose white hoods were painted brown (allopatric-looking) than were females from San Jorge. Although experimental females from both islands courted less than females from control pairs, experimental females from Marietas were five times less likely to copulate than control females, whereas there were no differences between treatments in propensity to copulate by females in San Jorge. Thus, in the brown booby, female dislike of foreign males may function as a reproductive barrier in populations close to contact zones, where the risk of possibly maladaptive hybridization is highest. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Birdsong in temperate zone passerines is a trait under sexual selection in males. Female song is still thought to be rare in this group. Here we show that female song is common in a temperate zone population of house wrens, Troglodytes aedon, and we provide evidence for its functional role in defending against male and female conspecifics. We observed that females sang most frequently at the onset of egg laying, with song becoming less common as incubation approached. Thus, females sang most during the time when eggs were left unguarded and susceptible to conspecific attack. We also conducted playback experiments to test whether conspecific stimuli would induce female song in focal individuals. Playback from both male and female conspecifics elicited strong song responses from resident females, who often vocalized independently from their partners. However, females were more physically aggressive towards female songs than male songs. Finally, females that sang more during these simulated conspecific intrusions ultimately lost fewer eggs to house wren ovicide. These results suggest that female house wren song may have evolved, at least in part, for use in intra-and intersexual competition. These results also highlight how investigating these traditionally male behaviours in female animals can lead to key insights regarding the evolution of sexual dimorphism. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Intergroup contests determine access to resources and influence the evolution of group living in social species. Asymmetries in resource-holding potential and payoffs should influence the outcome and intensity of such contests. We evaluated predictors of contest outcome and intensity using data collected over 40 months from 6 groups of wild blue monkeys, Cercopithecus mitis. We found increased odds of winning when a group was larger and used the contest site more than its opponent, and when contests occurred closer to the group's home range centre while farther from the opponent's centre. However, a larger difference in group size (across five pairs of opposing groups) did not predict a greater proportion of contests won by the larger group. Some evidence suggested increased odds of a draw when group sizes were more similar. In addition, contests were longer and more aggressive when groups were more similar in size and when the contest site was similarly central in both groups' home ranges. Contests were also more aggressive when the opposing groups' use of the contest site was more similar. Overall, asymmetries in resource-holding potential (i.e. group size) and/or payoffs related to the contest's location influenced a group's competitive advantage, the likelihood of a draw and the intensity of intergroup contests. Although comparable data are limited, it seems clear that both types of asymmetries can play a role in determining the outcome and intensity of intergroup contests, and that the relative power of each may vary across species. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Social relationships established early in life can have effects on social structure and influence individual fitness. Eastern grey kangaroos, Macropus giganteus, nurse their young for at least 18 months, allowing for a strong bond to develop between mothers and young. Because most female kangaroos are philopatric, the mother-offspring relationship established during lactation could persist into adulthood, resulting in clusters of female kin. Strong social bonds, however, are based on affiliative behaviours and frequent interactions. In particular, one might not expect strong bonds among related individuals unless there are advantages to interacting with relatives compared to associating with unrelated conspecifics. We examined development of the mother-offspring relationship in eastern grey kangaroos from permanent emergence from the pouch to the time of weaning. We studied a high-density population at Wilsons Promontory National Park, Victoria, Australia. There were few differences in the behaviour of sons and daughters towards mothers. However, daughters foraged slightly closer than sons to their mothers and daughters were weaned approximately 2 months later than sons if the mother did not have a surviving large pouch young. Mothers associated more closely with their daughters than their sons when offspring were aged 10-29 months but neither sex associated closely with their mothers beyond 33 months of age. Mothers never intervened to defend their young from aggressive individuals and it was the offspring that maintained spatial proximity to their mothers. Kangaroo mothers had few interactions with their juvenile offspring other than nursing. Females may be philopatric and settle near close kin as adults but kangaroos appear to have few of those early affiliative interactions necessary for social bonds to develop. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Arnold, Kathryn E.Gilbert, LucyGorman, Helen E.Griffiths, Kate J....
69-78页
查看更多>>摘要：The differential allocation hypothesis (DAH) predicts that an individual should vary its reproductive investment according to the attractiveness of its mate. A recently revised version of the DAH makes explicit that investment can be positive, i.e. higher for the offspring of attractive males which should be of higher quality, or negative, i.e. higher for offspring of unattractive males, for example compensating for inheriting poor paternal genes. Moreover, investment can be made by the father and the mother. Here, we tested whether experimental manipulation of male attractiveness affected parental investment at different reproductive stages and thus influenced fitness-related traits in offspring. In two aviaries, all male zebra finches, Taeniopygia guttata, were given red leg rings to increase attractiveness and in two aviaries all males received green leg rings to decrease attractiveness. This controlled for assortative mating between treatments. Ring colour was merely an experimental manipulation of male attractiveness, not paternal quality, so we might expect additional investment to elevate offspring quality. Eggs were cross-fostered between and within treatments to allow differentiation of effects of investment in eggs and nestlings. Clutch and brood sizes were standardized. Both positive and negative investment were observed: Eggs from red-ringed fathers had higher yolk to albumen ratios than eggs from green-ringed fathers. Nestlings from eggs laid and incubated by parents in the red-ringed group had higher hatching masses than those in the green-ringed group. Both parents in the green-ringed group fed nestlings more frequently than red-ringed parents. Offspring performance was influenced by the treatment of both foster and biological parents, but combined effects of these different investment patterns on fitness-related traits were ambiguous. Male attractiveness appeared to affect patterns of reproductive investment but not consistently across all forms of reproductive investment suggesting that the costs and benefits of differential allocation vary among individuals and across contexts. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Insect societies display a remarkable level of cooperation, but their colonies also represent a valuable resource that can be taken advantage of by genetically unrelated individuals. Indeed, several recent studies have documented cases of intraspecific reproductive parasitism, whereby workers penetrate and lay eggs in unrelated colonies in order to have their brood raised by the host workers. Previously, it has been predicted that queenless colonies should be a prime target of such intraspecific worker parasitism, as in such colonies the parasite workers would be able to reproduce without interference from either the queen or other workers. So far, this prediction has been supported with data from the honeybee, but evidence from other social insect groups is currently lacking. Here we present the first such test in the common wasp, Vespula vulgaris. In particular, workers from queenright colonies left the natal nest at a higher rate than those from queenless colonies. However, contrary to our predictions, drifter workers targeted queenless and queenright colonies equally. Chemical data suggest that this lack of discrimination may be linked to recognition constraints and the lack of volatile signals that reliably indicate the presence or absence of the queen. In addition, in queenright colonies, drifters activated their ovaries at a rate that was ca. five times higher than the natal workers. Overall, our results suggest that also in wasps, workers can gain inclusive fitness by drifting to unrelated nests, even if the chances of successfully reproducing there may be very slim. (C) 2015 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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