Biology subjects

Haigh, A.

Publications and source records attributed to Haigh, A..

5 recordsLinked to original sources

bioRxiv2024

Random subsamples of animal populations can reveal intrinsic differences in sociality with key implications in ecology, conservation and disease transmission

Animal populations are under mounting stress from the dual threats of climate change and rapid global human population growth, raising significant concerns about declining wildlife and the rising risk of zoonotic diseases. In many species, social interactions can be a highly plastic suite of behaviours that are responsive to these disturbances and are consequential to other processes like disease transmission and population dynamics. Studying social interactions can be challenging in that researchers often rely on wildlife population subsamples due to practical constraints and costs, which can introduce biases in the reliability of social network metrics. We investigated the extent to which subsamples can depict intrinsic characteristics of wildlife populations using data from three distinct species: peri-urban fallow deer, Alpine ibex and Angolan giraffe. We showed that random subsamples of these populations could still reveal differences in their social behaviour, indicating that, as long as researchers have a reliable estimate of population size, subsampling animal populations can be an effective and precise method to infer their sociality and offer valuable empirical data for management, conservation and zoonotic disease ecology. Furthermore, we demonstrate that non-random sampling, influenced for instance by animal personality and related trappability, can introduce significant biases in social network estimates. These findings underscore the importance of accounting for sampling biases in social network analysis and offer a robust framework for using partial networks in ecological studies and conservation management.

ecology↗

bioRxiv2024

Fallow deer approaching humans are also more likely to be seropositive for Toxoplasma gondii.

Toxoplasma gondii (T. gondii) is a trophically-transmitted protozoan parasite that has been suggested to facilitate its transmission by altering intermediate hosts anti-predator behaviour, thus increasing the likelihood of completing the cycle inside its definitive host i.e. domestic and wild felines. T. gondii has been linked to reduced risk-aversion, slower reaction times, and more exploratory behaviours in intermediate hosts, including most famously weakened aversion to the scent of feline predators in mice. Studies examining this phenomenon, however, have almost exclusively been carried out in laboratory conditions with small mammals, whereas little is known about the role of T. gondii within more complex ecological contexts involving large mammals in the wild. Under such scenario, the goals of our study were three-fold. Firstly, to determine the prevalence of T. gondii infection in a population of free-living fallow deer (Dama dama) living in a park at the edge of a metropolis. Secondly, to find a link between deer seropositivity and space use in the park, namely proximity to buildings with domestic cats, where deer may have been more likely to contract the disease. Finally, to determine whether infection with T. gondii was linked to risk taking behaviour in these free ranging large mammals, namely likelihood to approach park visitors. To achieve our goals, we estimated seropositivity and combined it with spatial distribution and behavioural data of individually-recognizable deer ranging from those that avoid humans (risk-avoiders) to those who beg for food (risk-takers). We found T. gondii to be quite widespread in this population with a seropositive of 20% (24 out of 120 individuals). Contrary to our expectations, we found no correlation between T. gondii seropositivity and space use in the park, therefore not allowing us to engage with the dynamics of disease contraction. We did however find that fallow deer taking the risk of approaching humans were also more likely to be seropositive. Are risk taking individuals more likely to contract the disease? Or, alternatively, do they take more risk because they have contracted the disease? The causal mechanism behind our result has yet to be disentangled, opening new scenarios in research aimed at tackling host manipulation in this parasite. It is a fact, however, that those animals that were more likely to be in contact with the public were also those more likely to be seropositive, adding key empirical evidence to the study of zoonotic diseases. Our study is a significant contribution on the transmission and maintenance dynamics of T. gondii, offering new insights on the need to conduct longitudinal studies able to disentangle the causal mechanism and T. gondiis ability to manipulate its intermediate host.

animal behavior and cognition↗

bioRxiv2023

Does fear of humans predict anti-predator strategies in an ungulate hider species during fawning?

Humans are a major evolutionary force on wildlife via artificial selection. While often explored through the lens of extractive interactions (e.g., hunting) able to favour certain behavioural traits over others, the implications of non-extractive ones, such as wildlife feeding, remain under-studied. Research has recently shown that people tend to feed (and sometimes favour) a limited subset of bolder individuals within natural populations, although its dynamics and consequences are not fully clear. Using fallow deer living in a peri-urban setting as a model population, we studied whether mother deer that display reduced fear of humans and consistently approach them for food adopt weaker anti-predator strategies by selecting for fawning bedsites that are less concealed and closer to human hotspots, allowing them to take advantage of additional artificial feeding opportunities in comparison to shier mothers in this population. Our dataset encompassed 171 fawns from 109 mothers across 4 years. Contrary to our expectations, we found that mothers that regularly accepted food from humans selected for more concealed bedsites farther away from them, giving their offspring better protection while also taking advantage of additional artificial food during lactating. Our results show marked behavioural adaptation by a subset of females, making this the first time that the link between tendency to approach humans and strategies to protect offspring is explored. Given previous findings that these begging females also deliver heavier fawns at birth, our research adds a piece to the complex puzzle describing human manipulation of behaviour in natural populations and its fitness consequences.

animal behavior and cognition↗

bioRxiv2023

Fawn bedsite selection by a large ungulate living in a peri-urban area

Human-wildlife conflict in expanding peri-urban and urban areas is of increasing concern, as a result of growing human populations along with the associated anthropogenic footprint on wildlife habitats. Empirical data from wildlife research carried out within human dominated landscapes are key to understanding the effects of human pressures on wildlife ecology and behaviour, exploring wildlife behavioural flexibility (or phenotypic plasticity), and informing wildlife management decisions. Here, we explored how female fallow deer (Dama dama) responded to human and dog presence during the birthing period in the largest walled urban park in Europe. We collected data on 477 bedsites utilised by 283 neonate fawns across three consecutive fawning seasons, gathered fine-scale data on humans and dogs space use, and built Resource Selection Functions at multiple spatial scales. We found that, when choosing bedsites to give birth and leave fawns unattended, fallow deer mothers significantly avoided hotspots of park visitors on foot (and their dogs) along the hiking trail routes. Bedsites were also unlikely to be in close proximity of paved roads used by vehicle traffic. Additionally, fallow deer mothers were found to select for dense understory vegetation for bedsites, providing low visibility to conceal their offspring. Our results provide detailed insights into bedsite spatial and habitat selection by a large herbivore in response to human activities, and we provide clear indications to wildlife managers to preserve established fawning sites and alleviate human-wildlife conflict during a critical period of the deer annual biological cycle.

animal behavior and cognition↗

bioRxiv2022

Neonate personality affects early-life resource acquisition in a large social mammal

Current debate in the field of animal personality revolves around whether personality is reflecting individual differences in resource allocation or acquisition. Despite the large body of literature, the proximate relationships between personality, resource allocation, and acquisition are still unclear, especially during early stages of development. Here we studied how among-individual differences in behaviour develop over the first 6 months of life, and their potential association with resource acquisition in a free-ranging population of fallow deer (Dama dama). We related proxies of neonate personality - i.e. neonate physiological (heart rate) and behavioural (latency to leave at release) anti-predator responses to human handling - to the proportion of time fawns allocated to scanning during their first summer and autumn of life. We then investigated whether there was a trade-off between scanning time and foraging time in these juveniles, and how it developed over their first 6 months of life. We found that neonates with longer latencies at capture (i.e. risk-takers) allocated less time scanning their environment, but that this relationship was only present when fawns were 3-6 months old during autumn, but not when fawns were only 1-2 months old during summer. We also found that time spent scanning was negatively related to time spent foraging - a relationship rarely tested in juveniles of large mammals - and that this relationship becomes stronger over time, as fawns gradually switch from a nutrition rich (milk) to a nutrition poor (grass) diet. Our results highlight a potential mechanistic pathway in which neonate personality may drive differences in early-life resource acquisition, through allocation, of a large social mammal.

ecology↗