Animal Behaviour最新文献

By changing the spatiotemporal availability of resources, tourism-related feeding can have potentially detrimental impacts on the movement ecology of animals, thus possibly undermining its own conservation benefits. A lack of baseline data on natural behaviour and the noninclusion of observation data that adequately incorporates the previous experience of animals with tourism-related feeding have generated contradictory results, causing the true impacts of feeding to remain obscure. Further, the relationship between the energy consumption of fed animals and their space use remains unexplored. Here, we coupled passive acoustic telemetry with previously published observation data at a tourism-related feeding site to investigate how direct feeding affects space use and residency patterns of great hammerhead sharks, Sphyrna mokarran, in Bimini, The Bahamas, at various timescales (ranging from days to 8 years). We first constructed movement models for 28 known fed and naïve sharks (i.e. those that were present at the study site but never attended feeding events) to quantify differences in space use and spatial overlap between those groups. We then compared bait uptake of fed sharks with their space use. Fed sharks showed a marked reduction in space use in response to feeding events and an amplification of these impacts over 5 consecutive years. In contrast, naïve shark space use remained unchanged over the same period. The seasonal residency of fed and naïve great hammerheads remained stable across 8 years, with the sharks leaving the study site during the summer of each year. Our study underscores how the intensification of tourism-related direct feeding progressively alters the space use of apex predators across short and long timescales, with enduring effects on fed animals. Our study further highlights the utility of a naïve animal group for assessing feeding impacts in the absence of baseline data.

Intraspecific variability in parasite virulence holds significant ecological and evolutionary implications as it can result in uneven costs incurred by individuals of a host species. Obligate brood parasites, birds that lay their eggs in the nest of another species and do not raise their own young, differ in interspecific virulence, as some species kill all host nestmates directly while other species do not. However, variation in the intraspecific virulence of a brood-parasitic species has rarely been investigated. One source of this variability could arise through sexual size dimorphism, because many brood-parasitic species are sexually dimorphic in size starting at the nestling stage, and nestling size often impacts competitive ability in the brood. Here, we investigated the sex-specific effects of nestling brood-parasitic brown-headed cowbirds, Molothrus ater, on one of their hosts, the prothonotary warbler, Protonotaria citrea. We predicted that larger male cowbird nestlings would cause host chicks to have lower survival and size and altered life history in the form of delayed fledging. Using experimentally parasitized broods, we found that although male brood-parasitic cowbird nestlings are heavier than females, there was no effect of cowbird sex on the survival, size or fledging phenology of the host nestlings. Furthermore, there were no differences in fledging phenology between the male and female cowbird chicks. Instead, we found that wing length, which was similar between the parasitic nestlings' sexes, was an important predictor for age and order of fledging. These findings show that the extent of development is critical for the timing of fledging of both parasitic and host species. Notably, the lack of effect of cowbird nestling sex on host chick survival and fledging suggests that the presence of a parasite is more influential for host nestlings than the size of parasites.

Heatwaves are becoming more common due to climate change. Species can respond to this thermal stress through rapid behavioural changes. For example, parental care can increase reproductive success by buffering against thermal stress, but the ability to provide parental care may also be influenced by prior exposure to high temperatures. However, the effects of heatwaves in parents' early development on parental care they provide in adulthood have not yet been tested. Here, we addressed this knowledge gap using the burying beetle Nicrophorus vespilloides, an ectotherm model system with facultative biparental care. We compared the parental behaviour, reproductive success and offspring fitness of parents that had been exposed to a heatwave (3 days at 25 °C) early in the pupae stage in their development and parents that had been reared at a constant temperature. Females from the heatwave treatment were more likely to provide care than those in the control treatment, with no difference in reproductive success or offspring fitness between thermal treatments. Our findings suggest that heatwaves during the pupae development stage can potentially have long-term impacts on the likelihood of providing parental care later in life.

Space use is widely assumed to be an important predictor of social behaviour given that animals are most likely to interact with nearby conspecifics. In the age of remote-sensing technology, spatial proximity is often used as a proxy for social interaction, although this simplifying assumption has rarely been tested under field conditions. Using 5 years of spatial and social data from direct observations of nearly 200 individually marked free-living California ground squirrels, Otospermophilus beecheyi, we employed social network statistics to evaluate the role of spatial relationships in generating individual differences in sociality. As predicted, range size was positively associated with each of the four social network metrics examined, confirming that more social squirrels generally had larger ranges. The proportion of range overlap between individuals was positively correlated with the strength of their social interactions, with the strongest ties occurring within age and sex classes and with juveniles generally being more social than adults. To determine whether these outcomes varied with interaction type, we examined the effects of spatial relationships on affiliative interactions, agonistic interactions and all interactions combined. We found that spatial relationships better predicted affiliative encounters compared to agonistic encounters. Despite revealing significant links between spatial and social relationships, our models explained only a small proportion of the variation in each social network metric examined. Thus, factors other than space use must contribute to social interactions, suggesting that general assumptions regarding the effects of space use on social interactions need to be evaluated on a species-by-species basis. More generally, these findings highlight the need for explicit consideration of the spatiosocial interface and its implications for multiple aspects of animal behaviour.

Social bonds are crucial to many animal species. To maintain these bonds, individuals must be able to differentiate the identity of conspecifics. Pair-bonding primates, in general, maintain close bonds with their selected mate. Little is known about visual preferences of pair-bonded primates. To characterize visual preference for images of familiar and unfamiliar faces, we assessed visual attention in coppery titi monkeys, Plecturocebus cupreus. Coppery titi monkeys, like many other pair-bonding species, show a behavioural partner preference when placed in a partner preference paradigm and maintain greater durations of physical proximity to their pair mate compared to an unfamiliar stranger. Using a previously validated noninvasive eye-tracking method, we investigated whether titi monkeys display visual partner preference. We presented adult titi monkeys with 10 static slides showing two conspecific faces side by side: either (1) their partner's face and a stranger's face, or (2) two strangers' faces. Face side was counterbalanced, and slide presentation order was randomized, across all subjects. We present five looking-behaviour outcome measures for a study of 40 titi monkeys. We found no evidence of a visual preference for still photographs of one's pair mate, but we did find that age, pair tenure and parenting experience predicted looking behaviour. Animals with longer pair tenures spent more time looking at facial images. Younger animals looked at the screen for the first time faster, spent less time looking and looked fewer times at the stimuli compared to older animals. Parenting status positively predicted fixation count, total visit duration and visit count, such that parents with more experience looked at the stimuli longer and more times than animals without parenting experience. This study is the first to characterize social looking in a pair-bonded monkey.