Sex-specific causes and consequences of variable testosterone circulation in a tropical songbird

Meeting Abstract

69-7  Sunday, Jan. 5 15:00 – 15:15  Sex-specific causes and consequences of variable testosterone circulation in a tropical songbird BOERSMA, J*; JONES, JA; KARUBIAN, J; SCHWABL, H; Washington State University; Tulane University; Tulane University; Washington State University

There is considerable debate about whether testosterone regulates traits similarly in male and female vertebrates. Meta-analyses of the relationship between male and female circulating testosterone have produced conflicting results, highlighting the need for empirical studies in species that exhibit variation in both male and female testosterone and the traits this hormone is known to mediate. The White-shouldered fairywren (Malurus alboscapulatus) demonstrates considerable subspecies-specific variation in testosterone circulation, behavior, and female ornamentation. Testosterone circulation in females appears to be linked to discreet female phenotypes: females from the subspecies with greater ornamentation and aggression circulated higher baseline testosterone, and unornamented females implanted with testosterone produced a major component of ornamental plumage and became more aggressive once the putative signal was acquired. Interestingly, males exhibited opposite patterns in baseline testosterone, as males from the unornamented female subspecies circulated the highest mean testosterone. Our findings challenge the idea that testosterone circulation is correlated and has similar function between sexes. We also present preliminary results from a long-term dataset quantifying variation in testosterone, social networks, and male sexual displays. We address how the social environment influences a suite of functionally linked traits and explore the causes and consequences of variable testosterone circulation between sexes.

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