title: Offspring Hormones Reflect the Maternal Prenatal Social Environment: Potential for Foetal Programming?
abstract: Females of many species adaptively program their offspring to predictable environmental conditions, a process that is often mediated by hormones. Laboratory studies have shown, for instance, that social density affects levels of maternal cortisol and testosterone, leading to fitness-relevant changes in offspring physiology and behaviour. However, the effects of social density remain poorly understood in natural populations due to the difficulty of disentangling confounding influences such as climatic variation and food availability. Colonially breeding marine mammals offer a unique opportunity to study maternal effects in response to variable colony densities under similar ecological conditions. We therefore quantified maternal and offspring hormone levels in 84 Antarctic fur seals (Arctocephalus gazella) from two closely neighbouring colonies of contrasting density. Hair samples were used as they integrate hormone levels over several weeks or months and therefore represent in utero conditions during foetal development. We found significantly higher levels of cortisol and testosterone (both P < 0.001) in mothers from the high density colony, reflecting a more stressful and competitive environment. In addition, offspring testosterone showed a significant positive correlation with maternal cortisol (P < 0.05). Although further work is needed to elucidate the potential consequences for offspring fitness, these findings raise the intriguing possibility that adaptive foetal programming might occur in fur seals in response to the maternal social environment. They also lend support to the idea that hormonally mediated maternal effects may depend more strongly on the maternal regulation of androgen rather than cortisol levels.
authors.affiliation: Department of Animal Behaviour, University of Bielefeld, Morgenbreede 45, 33615, Bielefeld, Germany.
authors.forename: Kristine
authors.initials: K
authors.lastname: Meise
authors.affiliation: Department of Animal Behaviour, University of Bielefeld, Morgenbreede 45, 33615, Bielefeld, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: von Engelhardt
authors.affiliation: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, United Kingdom.
authors.forename: Jaume
authors.initials: J
authors.lastname: Forcada
authors.affiliation: Department of Animal Behaviour, University of Bielefeld, Morgenbreede 45, 33615, Bielefeld, Germany.
authors.forename: Joseph Ivan
authors.initials: JI
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001947:Breeding; D005260:Female; D047109:Fetal Development; D046069:Fur Seals / Q000196:embryology* / Q000378:metabolism*; D005843:Geography; D006728:Hormones / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism*; D008962:Models, Theoretical; D018401:Sample Size; D012931:Social Environment; D013739:Testosterone / Q000378:metabolism*
chemical_list: D006728:Hormones; D013739:Testosterone; D006854:Hydrocortisone