查看更多>>摘要：Optimal foraging theory predicts that animals should attempt to maximize their food intake while exerting minimal energy. Thus, food sites should often be visited in order of proximity. However, resources vary in multiple attributes, so it may be beneficial to bypass some sites to visit others first. We used a foraging experiment on wild vervet monkeys (Chlorocebus pygerythrus) at Lake Nabugabo, Uganda to determine whether they prioritize high-reward food sites over low-reward sites. Five baited platforms were set in a pentagon within the range of one group. Trials usually consisted of single foragers but when multiple individuals participated, food competition occurred. In phase 1, platforms were baited equally. Individuals immediately found the shortest path and there was no relationship between experience and distance travelled. From phase 1, expected numbers of first visits to each platform were calculated for phases 2 and 3, where one or two platforms were six times more rewarding than others. In combined results from all trials with high-reward sites, individuals did not travel to highly rewarding platforms first, unless competitors were present. Vervets that foraged alone usually accessed food sites in order of proximity and saved on travel costs (consistent with a nearest-neighbour rule or a convex hull heuristic), regardless of the location of high-reward site(s); while monkeys in competition prioritized high-reward sites (a 'take-the-best' or gravity heuristic) and sometimes bypassed low-reward sites in an attempt to increase food acquisition at the expense of travel costs. When two sites were six times more rewarding, travel patterns changed to a greater focus on high-reward sites by single foragers and a tendency to ignore low-reward platforms. These results confirm that vervets integrate distance/reward information over multiple food sources, show spatial discounting in the right circumstances and optimize their routing decisions in different ways depending on the social context. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
LaDage, Lara D.Roth, Timothy C., IISinervo, BarryPravosudov, Vladimir V....
11-18页
查看更多>>摘要：Behaviours such as territoriality, navigation and acquisition of food resources depend on spatially based cognition, which has been positively associated with the hippocampus, the area of the brain responsible for spatial processing. We previously demonstrated that differential demands on spatial processing within the context of territoriality affect brain volume in the side-blotched lizard, Uta stansburiana: territorial males have larger cortices (reptilian hippocampal homologues) than nonterritorial males. However, it is still unclear whether these cortical differences are based on potential differences in experiences, genetic architecture, or a combination of both. In this study, we specifically focused on the role of experiences in the cortical phenotype. We hatched and raised territorial and nonterritorial males to adulthood, controlling for differential environmental experiences, and found that cortical volume did not differ between laboratory-reared territorial and nonterritorial males. Furthermore, when compared with wild-caught individuals, laboratory-reared individuals had significantly smaller cortical volumes, regardless of territorial predisposition. These results indicate that a large component of the differential cortical volume found between territorial and nonterritorial lizards in the wild must be experiential. Additionally, cortical volume is smaller in a captive environment, regardless of territorial predisposition. Our work indicates that experience, particularly experience with a simplified environment such as that found in captivity, dramatically limits the size of the cortices in this species. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Ants use the panoramic skyline in part to determine a direction of travel. A theoretically elegant way to define where terrestrial objects meet the sky is to use an opponent-process channel contrasting green wavelengths of light with ultraviolet (UV) wavelengths. Compared with the sky, terrestrial objects reflect relatively more green wavelengths. Using such an opponent-process channel gains constancy in the face of changes in overall illumination level. We tested the use of UV wavelengths in desert ants by using a plastic that filtered out most of the energy below 400 nm. Ants, Melophorus bagoti, were trained to home with an artificial skyline provided by an arena (experiment 1) or with the natural panorama (experiment 2). On a test, a homing ant was captured just before she entered her nest, and then brought back to a replicate arena (experiment 1) or the starting point (the feeder, experiment 2) and released. Blocking UV light led to deteriorations in orientation in both experiments. When the artificial skyline was changed from opaque to transparent UV-blocking plastic (experiment 3) on the other hand, the ants were still oriented. We conclude that UV wavelengths play a crucial role in determining direction based on the terrestrial surround. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Antipredator vigilance may take a significant amount of time, leading to a trade-off between foraging and vigilance. Studies show that this trade-off is modulated by the perception of predation risk faced by individuals. Anthropogenic noise can disturb acoustic communication by masking both direct predator detection and the perception of conspecific alarm calls. We would expect a decrease in acoustic awareness to be compensated for by an increase in visual awareness. Thus, we tested whether increases in noise produced by commercial aircraft reduced foraging effort and increased vigilance time in great tits. We videotaped birds feeding on peanut feeders in the vicinity of Barajas airport (Madrid, Spain), and measured behavioural sequences before, during and after aircraft sound events. Our results show that, when aircraft noise peaked, the proportion of time devoted to vigilance was maximal, while that devoted to feeding was minimal. As a result, the ratio between vigilance and foraging was at its maximum when aircraft noise was loudest, being almost double that during baseline levels. The duration of vigilance episodes was strongly correlated with noise levels. Also, the duration of feeding bouts was at its lowest during the peak of noise, and increased after this period. We suggest that these behavioural modifications help foragers visually detect possible predators in those situations in which high levels of noise hamper sound perception. Our study suggests that behavioural plasticity could contribute to the resilience of avian populations exposed to anthropogenic disturbance. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Despite rapid growth in the literature on personality in wild animals, personality has seldom been explored as a tool for wildlife management in human-altered landscapes. That context frequently involves the habituation of wildlife to people, which can alter predator-prey relationships, contribute to ecosystem damage and result in human-wildlife conflict. For many ungulate species, habituation is also associated with changes to facultative behaviours, such as migration, which may also be related to individual variation. We studied these relationships by identifying behavioural types in two wild populations of elk, Cervus canadensis, within which habituation is prevalent, and in one captive population. We defined behavioural types by the relative position of each individual along a shy-bold gradient that we derived for each population from seven behavioural metrics. Those metrics included repeated measures of reactions to three stimuli (approaching humans, novel objects and novel sounds), two state variables measured with scan samples (position within herd and vigilance) and two all-occurrence records of specific behaviours (outcome of dominance interactions and herd leading). Boldness scores were more similar within than among individuals in all three populations, consistent between years, and unrelated to age. In the wild, the shyer half of each population was three times more likely to exhibit migratory behaviour, whereas the bolder half was just as likely (3: 1) to express year-round residency. Our results suggest that personality could be an important tool for managing habituated wildlife. By identifying behavioural types and their associations with particular tendencies, managers could proactively target specific individuals for behavioural modification to foster greater coexistence of people and wildlife. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Liebl, A. L.Nomano, F. Y.Browning, L. E.Russell, A. F....
47-53页
查看更多>>摘要：Although theory developed to understand carer response rules in cooperative breeders typically predicts partial compensation, where additional investment by one carer is optimally met by incomplete reductions by the other, fully additive care is a viable alternative under particular conditions. Primary among these conditions is an opportunity for both existing and additional carers to gain comparable fitness from contributing to rearing offspring. That, in a number of cooperative birds, at least one parent often maintains its level of contribution to offspring rearing independent of carer numbers is supportive, but experimental evidence is lacking. Here, in naturally occurring groups of the cooperatively breeding chestnut-crowned babbler, Pomatostomus ruficeps, we found that provisioning rates of male carers were insensitive to the number of other males present; this resulted in an increase in total brood and per capita nestling provisioning rates across the range of total carer numbers tested (i.e. two - seven). Further, remaining male carers failed to change their provisioning rates following the temporary removal of one to three other males for up to 36 h, leading to significant decreases in total brood and per capita nestling provisioning. We found no obvious evidence to suggest that carer removals were otherwise disruptive and confounded the opportunity for remaining carers to respond. Our results confirm the existence of strongly additive care in cooperative breeders, and corroborate recent theory predicting that such response rules will arise when all carers in a group have the potential to contribute similarly to offspring success. (C) 2016 The Authors. Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd.
de Fouw, Jimmyvan der Heide, TjisseOudman, ThomasMaas, Leo R. M....
55-67页
查看更多>>摘要：Predators have evolved many different ways to detect hidden prey by using advanced sensory organs. However, in some environmental contexts sensory information may be obscured. The relation between sensory organs, obstruction and searching efficiency remains little explored. In this study we experimentally examined the ways in which a sensory system ('remote detection'), which enables red knots, Calidris canutus, to detect hard objects buried in wet soft sediments, is obstructed by plants. At an important coastal nonbreeding site of this species, the Banc d'Arguin (Mauritania, West Africa), most of the intertidal foraging area is covered by sea grass. The structurally complex networks of belowground roots and rhizomes and aboveground sea grass may obstruct information on the presence of buried bivalves and thus affect searching efficiency. Under aviary conditions we offered red knots buried bivalves in either bare soft sediments or in sea grass patches and measured prey encounter rates. Red knots detected prey by direct touch in sea grass but remotely in bare sediment. Physical modelling of the pressure field build-up around a probing bill showed that within a layer of sea grass rhizomes, permeability is reduced to the extent that the pressure field no longer reveals the presence of an object. In bare sediment, where searching efficiency is constant, red knot intake rate levelled off with increasing prey density (described by a so-called type II functional response). In the sea grass beds, however, prey density increases with sea grass density and simultaneously decreases searching efficiency, which will at some point lead to a decrease in intake rate when prey densities increase (i.e. a type IV functional response). Clearly, prey detection mechanisms dictate that the combined effects of prey density and habitat complexity should be taken into account when predicting forager distributions and habitat preference. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The solar day-night rhythm imposes a strict diel activity pattern on many organisms. Among birds, most species are generally either active during the day and rest during the night, or vice versa. However, many waterbird species can be active during both daylight and darkness. Hence, these species are much less limited by an external clock to allocate their activities over time than species showing a strict day or night pattern. Before miniaturized data-logging systems became available, it was difficult to follow animals day and night. Therefore, few details about short-term activity budgets are available for free-living animals. To study the activity budget of mallards, Anas platyrhynchos, in relation to time of the day, season and external factors, we used tags containing an accelerometer providing detailed activity information. We observed a relatively constant diel pattern with more activity during daylight than at night and peak activities during twilight. Activity over the season (September-April) was remarkably constant. Compared to the average activity per half-day, excess activity alternated every 12 h, suggesting an increased need for rest during daylight after a night with excess activity, and vice versa. Between days, activity was allocated to half-days in a very flexible manner: Either day or night activity was increased for a number of days, before increased activity gradually switched to the other half-day. We observed no synchrony in this pattern among individuals, highlighting the behavioural flexibility of this generalist species. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd.
Wright, Brianna M.Stredulinsky, Eva H.Ellis, Graeme M.Ford, John K. B....
81-95页
查看更多>>摘要：The vast majority of social animals exhibit sex-biased dispersal as a strategy to reduce kin competition and avoid inbreeding. Piscivorous 'resident' killer whales, Orcinus orca, of the eastern North Pacific, however, are unusual in that both sexes remain philopatric throughout life, forming highly stable, multigeneration matrilines that are closed to immigration. We conducted a 12-year study documenting extensive cooperative prey sharing within these matrilines, and hypothesized that extreme natal philopatry in resident killer whales arose due to inclusive fitness benefits gained by provisioning maternal kin. We found that prey sharing was nonreciprocal, and even though whales routinely foraged in mixed associations containing multiple matrilines, prey sharing among individuals belonging to different matrilines was very infrequent. Furthermore, maternal relatedness was a significant predictor of the frequency of prey sharing between individuals, with close maternal kin sharing more often than distant relatives or nonkin. Adult females were much more likely to share prey than adult males or subadults, probably because they mainly provisioned their offspring. However, food sharing was not limited solely to maternal care; all age-sex classes engaged in this behaviour by sharing with close maternal relatives, such as siblings and mothers. We also investigated the frequency of prey sharing between mothers and their offspring as a function of offspring sex and age, and found that maternal food sharing with daughters declined after daughters reached reproductive maturity, which could help to explain matriline fission events. The evolution of kin-directed food sharing requires the ability to reliably discriminate kin, which resident killer whales likely achieve through social familiarity and vocal dialect recognition. We propose that lifetime philopatry of both sexes has been selectively favoured in this population due to the inclusive fitness benefits of kin-directed food sharing, a cooperative behaviour that may also inhibit dispersal by reducing resource competition among kin. Crown Copyright (C) 2016 Published on behalf of The Association for the Study of Animal Behaviour by Elsevier Ltd.
查看更多>>摘要：Social complexity is often thought of as a driving force in the evolution of communication and cognition, but this is at odds with the fact that nonhuman primates generally display only very limited flexibility in vocal production. Some primates partially overcome their limited vocal flexibility by combining two or more acoustically inflexible calls into complex sequences. Equally relevant is that some primate calls consist of separable morphological elements whose combinations create different meanings. Here, we focus on the vocal system of wild female Diana monkeys, Cercopithecus diana, which produce three call units (R, L, A) either singly or merged as RA or LA call combinations. Previous work has shown that R and L convey information about external events, while A conveys information about caller identity. We tested this hypothesis experimentally, by broadcasting artificially combined utterances to eight adult females. To test the significance of the R and L 'event' units, we merged them with the A 'identity' unit of a group member. To test the significance of the 'identity' unit, we merged an R 'event' unit with an 'identity' unit from a group member or a neighbouring individual. Subjects responded in ways that suggested that both event and identity units were relevant, suggesting that Diana monkeys' social calls possess morphosemantic features. We discuss this finding in relation to the coevolution of communication and social complexity in primates. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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