Abstract:
Inmale 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.Weexplored 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.Weblocked androgen receptors, in the field, by treating subordinate
males with the antiandrogen, flutamide. We monitored androgen concentrations (via baseline serum and timesequential
fecal sampling) and recorded behaviorwithin 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.
