查看更多>>摘要：In many animals, the nontrivial cost of ejaculate production has led males to evolve prudent reproductive strategies in the form of precopulatory mating bias and/or cryptic ejaculate allocation. Behaviours determining male reproductive success, such as courtship and aggression, also impose substantial costs potentially selecting for plasticity in these traits. Here, using laboratory-adapted populations of Drosophila melanogaster, we investigated whether males show plasticity in these behaviours in response to the changes in their perception of future risk of competition (generated by varying the number of rivals). We show that males exhibited nonlinear plasticity in their aggressive behaviour. Males subjected to intermediate risk were found to show the maximum level of aggression compared to those subjected to low and high risk. Such plasticity in aggression did not lead to any variation in mating success but significantly increased the cost of reproduction. We also found a similar trend in courtship behaviour. While our results on copulation duration confirmed the previously reported plasticity, we did not find any effect of the treatment on mating latency. To the best of our knowledge this is the first empirical evidence showing plasticity in aggression in response to perceived risk of future competition and its relation to the cost of reproduction. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Researchers from various disciplines have hypothesized a positive correlation between the level of intergroup contest competition (IGCC) and the evolution of behavioural traits, such as cooperation, altruism and friendship, which promote intragroup affiliation. Empirical support for this hypothesis is, however, scarce and mainly available from humans. We tested whether the level of IGCC affects intragroup affiliation (i.e. intragroup grooming exchange) among male and female nonhuman primates. To quantify intragroup affiliation, we used social network measures and a grooming index. Our measure of IGCC combined frequency of intergroup encounters and proportion of aggressive encounters and was calculated separately for males and females. We ran our analyses on 27 wild groups of primates belonging to 15 species (13 Cercopithecinae, one Colobinae and one Cebinae). Our analyses reveal a clear pattern of correlated evolution between grooming network density and interindividual variation in the number of grooming partners on the one hand and the intensity of IGCC on the other in females, but not males. Thus, our results suggest that the exact nature of the relationship between IGCC and intragroup affiliation is sex specific. These results may be explained by the differential costs and benefits males and females experience during aggressive intergroup confrontations and by sex-specific differences in intragroup affiliation. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The social intelligence hypothesis proposes that social complexity selects for cognitive complexity. However, the role of social complexity in the evolution of nonsocial cognition remains unresolved, resulting in disparate hypotheses. The domain-specific hypothesis posits that sociality only bolsters cognition associated with social challenges and contends that ecological complexity drives the evolution of nonsocial cognition. Alternatively, the domain-general hypothesis argues that the unmatched selective pressures of sociality favour greater cognitive flexibility and ultimately superior general cognition. We tested these hypotheses through experimental comparisons of nonsocial cognition in social and asocial carnivores: lions, Panthera leo, spotted hyaenas, Crocuta crocuta, leopards, Panthera pardus, and tigers, Panthera tigris. We tested subjects using a technical task, a puzzle-box, designed to test innovation. Social species were more successful innovators than asocial species. We also observed a positive association between sociality, persistence and innovation; social species spent significantly more time engaged in the task, and persistent individuals were more successful in solving the task. Thus, our findings support the domain-general hypothesis; social carnivores outperformed asocial carnivores on an innovative problem. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Humans and animals show cooperative behaviour, but our understanding of cooperation among unrelated laboratory animals is limited. A classic test of cooperation is the iterated Prisoner's Dilemma (IPD) game, where two players receive varying payoffs for cooperation or defection in repeated trials. To determine whether unrelated rats cooperate in the IPD, we tested pairs of rats making operant responses to earn food reward in 25 trials/day. The operant chamber was bisected by a metal screen with a retractable lever and pellet dispenser on each side. When levers extended, rats had 2 s to respond. Mutual cooperation (Reward) delivered three pellets each, mutual defection (Punishment) provided no pellets, and unilateral defection (Temptation) gave five pellets to the defector, while the partner (Sucker) received none. In eight pairs of males (RM-) and females (RF-), cooperation was defined by withholding a response. In seven pairs of RM+ males, cooperation was defined by responding on the lever. In males, food restriction significantly inhibited both cooperation and pellets received. There was no effect of dominance status. Males and females made similar numbers of responses under ad libitum feeding. However, neither food restriction nor dominance status affected responses in females. Rats were subsequently tested for reciprocity in 24 alternating trials/day. A response on the lever within 5 s delivered three pellets to the partner. Females made significantly more responses for their cage-mate than males. Responses within pairs were significantly correlated for males, but not for females. For both sexes, responses declined significantly when paired with an unfamiliar partner who never reciprocated ('bad stooge'). These results demonstrate that rats working for food show cooperation in IPD and direct reciprocity. Their responses depend on food availability and responses of their partner. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Joyce, Brendan J.Demers, Ebony E. M.Chivers, Douglas P.Ferrari, Maud C. O....
37-43页
查看更多>>摘要：Recent studies have established that variation in background level of risk has profound effects on antipredator phenotypes. Elevated levels of background risk not only change behaviour, but also physiology, morphology and cognitive function. A variety of prey show neophobic predator avoidance when exposed to short-term elevation in risk. Such phenotypically plastic responses allow prey to balance behavioural trade-offs in the face of uncertain risks. Here, we test the hypothesis that ontogeny functions as a constraining factor in the induction of neophobic predator avoidance. In a series of laboratory trials, we exposed convict cichlids, at three different ontogenetic stages (eggs/wrigglers, juveniles and adults), to conditions of elevated (versus low) risk and tested their response to a novel predator odour (rainbow trout, Oncorhynchus mykiss). When cichlids were exposed as eggs and newly hatched 'wrigglers' and tested 21 days later, they showed a significant antipredator response to trout odour. When exposed as similar to 18 mm juveniles, cichlids showed a significant avoidance when tested 24 h post-exposure, but not 21 days post-exposure. However, when conditioned as similar to 50 mm adults, we found no evidence of induced neophobia. Combined, these results suggest that ontogenetic stage may limit phenotypically plastic neophobia. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Theory suggests that behaviours previously thought only to influence intrasexual selection, such as aggression between males, can also be co-opted to serve in intersexual selection as honest indicators of male quality. Our previous research revealed an audience effect: male Jamaican field crickets, Gryllus assimilis, fight more aggressively in front of a female audience. One way for this to evolve is if females are more attracted to more aggressive males or fight winners. Given the potential interplay between intra- and intersexual selection, we investigated how observing a fight influences subsequent female mate choice and mating behaviour. We utilized two female treatments: Observers watched the two males fight, whereas Non-observers watched two noninteracting males. We then immediately tested Observer and Non-observer females for their mating preferences towards male fight participants using dichotomous and no-choice tests. Our approach enabled us to assess whether females preferred either dominant (winner) or subordinate (loser) males and whether females gathered information about males while watching them fight that informed their mating preferences. While females did not prefer fight winners over losers in dichotomous choice tests, in the no-choice tests, females were more likely to mount winners and mount males that they had preferred in the dichotomous choice tests. Intra-and intersexual competition appears to be mutually reinforcing in this species, but eavesdropping is unlikely to explain the evolution of audience effects. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Tennessen, Jennifer B.Parks, Susan E.Tennessen, Travis P.Langkilde, Tracy...
53-61页
查看更多>>摘要：Environmental noise is increasing worldwide, limiting the space available for species to send and receive important acoustic information. Many invasive species produce acoustic signals that alter the spectrotemporal characteristics of available signalling space. This provides an opportunity to test ideas about competitive exclusion by quantifying whether species with shared requirements for acoustic resources will become excluded or partition resource use to permit coexistence. We conducted a field playback experiment to test whether native treefrogs (green treefrogs, Hyla cinerea; pine woods treefrogs, Hyla femoralis) modify their acoustic behaviour to minimize acoustic competition from chorus noise of the invasive Cuban treefrog, Osteopilus septentrionalis. We demonstrate that noise from an invasive species differentially affects the vocal behaviour of native species. Those with similar calls (H. cinerea) shortened calls, called louder and persisted calling in response to masking stimuli while those with different calls (H. femoralis) did not modify behaviour. This evidence suggests that acoustic competition by invasive O. septentrionalis has altered the acoustic community structure, identifying acoustic competition as a mechanism by which invasive species can impact communities. Furthermore, these results broaden the concept of noise pollution, demonstrating fitness-relevant consequences of noise produced by invasive species. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Stutchbury, Bridget J. M.Fraser, Kevin C.Silverio, CassandraKramer, Patrick...
63-68页
查看更多>>摘要：In long-distance migrants, it has been hypothesized that re-pairing in spring is facilitated if, on the wintering grounds, formerly mated individuals maintain close proximity or occupy ecologically similar habitat, which then results in more synchronized spring migration schedules. For songbirds, pair members have long been thought to migrate independently, but only recently has it been possible to directly track start-to-finish migration to test this prediction. We used light-sensor geolocators to track paired versus nonpaired purple martins, Progne subis subis, that breed in North America and winter in South America. In 6 of 12 pairs, pair members departed on autumn migration within 4 days of each other, but pairs rarely occupied nearby stopover sites in Central America and were separated by an average of 560 km upon arrival in Brazil. Formerly paired birds were not significantly more similar in autumn or spring migration timing, or winter roost location, compared with nonpaired birds tracked from the same colonies and years. Formerly mated pairs who were closer together in Brazil, or who occupied regions with similar amounts of forest cover, did not have more synchronized spring migration schedules. Only 1 of 12 pairs that were tracked remated after migration. Intense competition for nesting cavities combined with disparate spring migration schedules of former pairs probably contributes to the high divorce rate. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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