Beyond Aggression: Androgen-Receptor Blockade Modulates Social Interaction in Wild Meerkats

Document Type

Article

Publication Title

Hormones and Behavior

Publication Date

2-2016

Keywords

antiandrogen, flutamide, testosterone, aggression, communication, prosocial behavior, behavioral neuroendocrinology, subordinate male, field experiment, cooperative breeder

Abstract

In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role within a status class, particularly among subordinates, is underappreciated. Recent evidence, especially for monogamous and cooperatively breeding species, suggests broader androgenic mediation of adult social interaction. We explored the actions of androgens in subordinate, male members of a cooperatively breeding species, the meerkat (Suricata suricatta). Although male meerkats show no rank-related testosterone differences, subordinate helpers rarely reproduce. We blocked androgen receptors, in the field, by treating subordinate males with the antiandrogen, flutamide. We monitored androgen concentrations (via baseline serum and time-sequential fecal sampling) and recorded behavior within their groups (via focal observation). Relative to controls, flutamide-treated animals initiated less and received more high-intensity aggression (biting, threatening, feeding competition), engaged in more prosocial behavior (social sniffing, grooming, huddling), and less frequently initiated play or assumed a ‘dominant’ role during play, revealing significant androgenic effects across a broad range of social behavior. By contrast, guarding or vigilance and measures of olfactory and vocal communication in subordinate males appeared unaffected by flutamide treatment. Thus, androgens in male meerkat helpers are aligned with the traditional trade-off between promoting reproductive and aggressive behavior at a cost to affiliation. Our findings, based on rare endocrine manipulation in wild mammals, show a more pervasive role for androgens in adult social behavior than is often recognized, with possible relevance for understanding tradeoffs in cooperative systems.

Funding Source

This research was supported by the National Science Foundation (IOS-1021633 to CMD), with contributions from the Swiss National Science Foundation (31003A_13676 to MBM). TCB was supported by a Natural Environment Research Council grant (RG 57058). Cambridge, Duke, and Zurich Universities supported the KMP during the span of this study.

Comments

This article was originally published as delBarco-Trillo, Javier, Greene, Lydia k., Goncalves, Ines Bragga, Fenkes, Miriam, Wisse, Jillian H., Drewe, Jillian H., Manser, Marta B., Clutton-Brock, Tim, Drea. Christine M. (2016) Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats. Hormones and Behavior, (79): 95-106. https://doi.org/10.1016/j.yhbeh.2015.11.001.

DOI

https://doi.org/10.1016/j.yhbeh.2015.11.001

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