Animal Behaviour最新文献

Migratory connectivity describes the degree to which migratory populations are mixed across space and time. Unlike adults, subadult birds often exhibit distinct migratory patterns and continually refine their migratory behaviour and destinations as they mature. Consequently, the influence of subadult movements on overall migratory connectivity might be different from that of adults. However, current studies on migratory connectivity often overlook population age structures, predominantly focusing on adults. In this study, we investigated the role of subadult movements in shaping population level connectivity by using satellite tracking data from 214 black-necked cranes, Grus nigricollis, in western China. We first assessed the variances in spatial separation in different age cohorts using the continuous temporal Mantel correlation coefficient with data from 17 juveniles tracked in the same year for 3 consecutive years. We then calculated the continuous temporal migratory connectivity for the entire population (comprising various age groups) from 15 September to 15 November and compared the result to that of the family group (consisting of juveniles and adults only). Our results revealed a positive correlation between temporal variation in spatial separation and age after the juveniles separated from the adults, suggesting that subadults may have fine-tuned their migration paths. Moreover, the migratory connectivity of the all-age cohort was moderate (below 0.6) in the winter season, and notably lower than that of the family group during the autumn period. Given the considerable impact of subadults on migratory connectivity, we recommend using data collected from birds across all age categories to improve the precision of population level migratory connectivity estimates.

Sound exposure studies require replicated sound treatments for the results to be representative for sound classes in general. Additionally, reused treatments in replicated designs need to be accounted for statistically. The lack hereof is referred to as simple and sacrificial pseudoreplication, respectively, and results should be interpreted accordingly. We quantified the occurrence of these issues and subsequent interpretation of results in 104 underwater sound exposure studies (2019–2023). The majority of the studies (85%) did not replicate sound treatments. From the ones that did, most did not statistically acknowledge the hierarchical structure of the data. Unreplicated treatment designs limit the generalizability of the findings. Nevertheless, only small differences were found in how the results of unreplicated and replicated treatment designs were interpreted. This commentary aims to provide guidance in the design, analysis and interpretation of sound exposure studies, which are equally valid for aquatic and terrestrial research.

An animal's behavioural traits can influence the outcomes of ecological interactions within their food web, including what they eat, their vulnerability to predation and who they compete with. Despite this, few studies have directly measured links between among-individual behavioural and trophic variation. Invasive species like the round goby, Neogobius melanostomus, are often found to have consistent among-individual differences in behaviour within and between populations across their invasion front. Therefore, an individualized approach to invasive populations and their ecological interactions may be valuable to understanding their impacts on recipient ecosystems. Using nonlethal methods to measure trophic variation (i.e. stable isotope analysis via fin clips) and passive individual tagging, we analysed behavioural trait/personality variation and trophic variation to explore links between the two. Focusing on an established population of round gobies in the Guldborgsund strait in the southwest Baltic Sea, we found significant among-individual variation in bold–exploratory traits in novel environment and refuge emergence assays. We also found strong intraspecific trophic variation, with particularly high variation in carbon-12 – carbon-13 (δ¹³C), suggesting that individual round gobies differ in what they are feeding on and/or where they forage. Diet reconstruction results support previous studies showing that gastropods and bivalves are major contributors to their diet, but the large differences in isotope values suggest that individual variation influences how they interact with prey communities. There were few links between behavioural and trophic variation; nevertheless, this study shows that measuring behavioural–trophic links is a viable approach for exploring whether and how behavioural traits may influence individual level ecological variation.

While wildlife tourism may impact the animals it targets, it plays a critical role in public education and conservation awareness. Understanding changes in animal behaviour in response to tourism activities can inform the trade-offs between negative impacts and socioeconomic benefits. There are public claims that cage-diving activities may condition white sharks, Carcharodon carcharias, to interact with boats, and may potentially increasing risk of shark bites. We tracked the fine-scale movements of 73 white sharks in relation to cage-diving boats using acoustic telemetry between 2018 and 2022 at Neptune Islands, Australia, to investigate associative behaviour and factors potentially influencing residency and time spent in proximity to the cage-diving boats. White sharks spent gradually less time near cage-diving boats throughout their residency at the tourism site. This behaviour was consistent across individuals, years, sexes and sizes. Sharks, however, resumed their natural behaviours (i.e. initial amount of time near the cage-diving boats) each time they returned to Neptune Islands, suggesting that the observed habituation (i.e. loss of response to the stimulus used to attract sharks) did not last for long periods. These trends support the lack of long-term learnt behaviour of white sharks increasingly interacting with boats. Our results indicate that current management strategies such as regulating the number of days the industry can operate at the site and the amount of food-based attractant used, and reducing the amount of bait consumed can limit associative behaviour between white sharks and boats, while enabling continued opportunities for white shark tourism. Understanding how wildlife associate with humans can help ensure that best practices are in place for both the targeted animals and the people involved, particularly in the case of threatened and potentially dangerous species.

This study analyses behavioural adaptations in a recently discovered European cave fish. Navigation in standardized labyrinth conditions was compared between this cave fish, its epigean ancestor, the European stone loach, Barbatula barbatula, and hybrid specimens. Loach behaviour was tracked and recorded using an infrared camera. In open field tests, in both dark and light conditions, cave loaches showed reduced thigmotaxis compared to the other two groups. Hybrid loaches generally showed strong avoidance of the open field, whereas epigean loaches avoided the open field more in light than in dark conditions. Other tests were performed in darkness only. Cave loaches showed more consistent lateralization in turning behaviour during exploration of the Y-maze than the other two groups, indicating a search strategy optimized for nonvisual navigation. In all groups, complex maze learning was evident in the first half of the 15 trials, with a reduction in latency of departure from the starting chamber, and in both time and track length to reach the food chamber. However, cave loaches were far more successful in finding food than were epigean loaches and hybrid loaches. When the path to the food chamber was altered, epigean loaches generally responded by changing their route, whereas cave loaches tended to continue following a previously learned path and hybrid loaches exhibited intermediate behaviours. In conclusion, the enhanced ability of cave loaches to navigating labyrinths in the dark compared to their epigean ancestor suggests the evolution of behavioural traits that optimize survival in caves.

Wildlife movement in urban environments can differ significantly from that in natural environments due to intrinsic factors (individual phenotype) as well as extrinsic factors (such as changes to the landscape and increased interactions with people). Here, we used tracking collars equipped with 1 Hz GPS to investigate the variation in fine-scale movement (individual step lengths, path tortuosity and residence times) of chacma baboons, Papio ursinus, across natural and urban environments in Cape Town, South Africa. We showed that the baboons exhibited limited interindividual differences in average movement (intrinsic factor: behavioural type), but large differences across environment (extrinsic factor: behavioural plasticity), where all baboons travelled faster and straighter, and spent less time in one location, when in urban space compared to natural space. We showed large intraindividual differences in baboon movement (behavioural predictability), indicating that some individuals exhibit greater consistency in movement than others. Finally, we showed an interaction between individual (ID) and environment (urban) for all metrics, where individuals differed in how much their movement in urban space changed compared to their movement in natural space. The individuals that changed their movement the most tended to be higher-ranking, socially connected baboons, which are the focus of the city's baboon management programme, seeking to keep baboons out of urban areas. We therefore suspect these changes in movement between natural and urban space to be partly a result of human–baboon interactions. Taken together, our results show how individual animal movement can be impacted by changing environments, affecting certain baboon phenotypes more than others.

Analysing social behaviour provides valuable insights into the dynamics of species living in groups. An essential part of social behaviour is represented by lead-and-follow interactions as they influence group stability through individual needs and decision making. In horses, Equus ferus caballus, this behaviour plays a crucial role since individuals depend on the security and knowledge their group offers. Only one study has analysed the lead-and-follow behaviour of Przewalski's horses, Equus ferus przewalskii. However, no such study has been conducted on the wild population, nor on the potential impact of the horses' origin and experience. We filmed 34 wild-born and captive-bred individuals with different experiences (held in a fenced enclosure before release into the wild, long-term reintroduced and wild-born) in the Great Gobi B (Mongolia) over summer 2018, late spring 2019 and autumn 2019 to investigate Przewalski's horses' lead-and-follow behaviour in situ. We documented lead-and-follow interactions within 11 groups and used these data to construct lead-and-follow networks. We also examined the influence of various social factors (origin, sex, age, dominance rank, group size, parity, kinship and time belonging to the group) on different network measures. The analyses revealed that wild-born horses with greater experience in the area tended to exhibit well-defined lead-and-follow connections with few leading individuals, typical of stable groups of horses. In contrast, in inexperienced reintroduced groups, many (or all) members controlled the movement. The results show that newly formed groups of released Przewalski's horses require time to develop typical and stable lead-and-follow patterns.

Predation is a powerful driving force leading to the evolution of antipredator defences in prey. The effectiveness of the antipredator defences can depend on various ecological contexts such as predator density and the development stages of the prey species. Males and females often exhibit remarkably different morphologies, behaviours and life histories, and the sexual differences are expected to generate different ecological contexts for males and females, potentially driving the evolution of sex-specific antipredator defences. In the horned beetle Gnatocerus cornutus, males have enlarged mandibles, but females lack this exaggeration. As potential defences against predators, these beetles either become immobile or run away. In this study, we established populations subjected to sex-specific predation. We found that male locomotion was increased in populations subjected to male-specific predation and that female immobility was increased in populations subjected to female-specific predation. We also found that males appeared on the surface of food resources more frequently than females. Given such differences in microhabitat preferences, the males are more likely to be detected by predators than the females. The sexual differences in morphology and microhabitat preferences may generate different predatory environments for males and females, resulting in males using locomotion to escape from predators and females using immobility to hide from them. In this laboratory selection experiment, we did not observe the evolution of the opposite sex's antipredator traits in response to sex-specific predation. We detected no intersexual genetic correlation of immobility and locomotion. The genetic decoupling and different predatory contexts for the two sexes may promote sexually different antipredator defences in G. cornutus.

Hatching asynchrony is understood as a female tactic that shapes family dynamics, but its adjustment mechanisms and adaptiveness remain unclear. Using 32 years of individual data on a Neotropical seabird, the blue-footed booby, Sula nebouxii, we examined variation in hatching asynchrony in relation to sea surface temperature, a proxy for food abundance, and hatching asynchrony's adaptiveness. Under warm sea surface temperature, signalling low food abundance, females extended laying interval, resulting in increased hatching asynchrony. Longer hatching asynchrony was associated with more probable and earlier brood reduction. When brood reduction occurred, longer hatching asynchrony improved females' prospect of breeding the next year but not their timing of laying or production of fledglings and recruits. By extending laying interval, female boobies increase hatching asynchrony to cope with poor food conditions by prompting early brood reduction, thereby reducing reproductive costs and enhancing the probability of breeding the next year. Understanding the temperature sensitivity of plastic reproductive traits is crucial for predicting organisms' responses and resilience to global warming.