Abstract
Behavioural variation at the individual level has been shown to play an important role in animal ecology and evolution. Whereas most studies have focused on subadult or adult subjects, neonates have been relatively neglected, despite studies showing that neonates can exhibit consistent inter-individual differences during early developmental stages. Steroid hormones, including glucocorticoids (e.g. cortisol) and androgens (e.g. testosterone), play a crucial role in foetal development and maturation and could therefore drive neonate behaviour, although this relationship is poorly understood in wild animal populations. Our study addresses these knowledge gaps by investigating the association between neonate fallow deer Dama dama fawn inter-individual variability in behavioural response to human handling and hair cortisol and testosterone levels. We found strong evidence that individual neonates display repeatable differences in the way they cope with a risky situation during their first days of life, and showed how these differences are linked to cortisol and testosterone levels accumulated in utero. We showed that, when both steroids are included in the same model, neonates with high cortisol and low testosterone levels coped in a more proactive way with human handling (higher heart rate during handling and shorter latency to leave when released) compared to those with low cortisol and high testosterone levels (lower heart rate and longer latency to leave). These results provide novel insights into the proximate mechanism leading to neonate inter-individual variation in a wild population of large mammals. A free Plain Language Summary can be found within the Supporting Information of this article.
| Original language | English |
|---|---|
| Pages (from-to) | 1255-1267 |
| Number of pages | 13 |
| Journal | Functional Ecology |
| Volume | 35 |
| Issue number | 6 |
| Early online date | 24 Mar 2021 |
| DOIs | |
| State | Published - Jun 2021 |
Bibliographical note
Publisher Copyright:© 2021 The Authors. Functional Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society
Funding
The authors thank the anonymous reviewers who contributed significantly to this manuscript with their constructive feedback. They thank the Office of Public Works (OPW), Ireland, for funding (grant no. R18625) and support. They extend a special thanks to Margaret Gormley (Chief Parks Superintendent), Paul McDonnell (Parks Superintendent), Maurice Cleary (chief of staff), Terry Moore (deer keeper), each of the OPW rangers and the extended OPW staff in the Phoenix Park—without whom the study would not have been possible. They thank the School of Biology and Environmental Sciences (SBES) in University College Dublin (UCD) for co‐funding this project. They are indebted to Billy Clarke and several UCD students for their invaluable help during fawn tagging. Finally, they thank Crispin Rodwell for the photographs taken, which are used in the plain language summary. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors declare that they have no conflict of interest. Open access funding provided by IReL. WOA Institution: University College Dublin; Blended DEAL: IReL. The authors thank the anonymous reviewers who contributed significantly to this manuscript with their constructive feedback. They thank the Office of Public Works (OPW), Ireland, for funding (grant no. R18625) and support. They extend a special thanks to Margaret Gormley (Chief Parks Superintendent), Paul McDonnell (Parks Superintendent), Maurice Cleary (chief of staff), Terry Moore (deer keeper), each of the OPW rangers and the extended OPW staff in the Phoenix Park?without whom the study would not have been possible. They thank the School of Biology and Environmental Sciences (SBES) in University College Dublin (UCD) for co-funding this project. They are indebted to Billy Clarke and several UCD students for their invaluable help during fawn tagging. Finally, they thank Crispin Rodwell for the photographs taken, which are used in the plain language summary. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors declare that they have no conflict of interest. Open access funding provided by IReL. WOA Institution: University College Dublin; Blended DEAL: IReL.
| Funders | Funder number |
|---|---|
| Margaret Gormley | |
| Office of Public Works | R18625 |
| University College Dublin |
Keywords
- animal personality
- coping
- cortisol
- fallow deer
- hair-testing
- pace-of-life
- temperament
- testosterone