Meeting Abstract
The reproductive benefits and health costs of androgens are well studied in males, but underappreciated in females, despite substantial variation in female androgen production. In the cooperatively breeding meerkat (Suricata suricatta), raised androgens may improve the competitive abilities of dominant females, ensuring their near-exclusive control over reproduction. If, as in the males of some species, female meerkats suffer from androgen-mediated immunosuppression, rank-related differences in androgens could produce rank-related effects on immunocompetence. Previously, we showed that (a) dominant females were the most heavily parasitized group members (Smyth & Drea, 2015), (b) within females, parasitism correlated with fecal androgen concentrations (Smyth et al. in prep), and (c) dominant females routinely have higher concentrations of sex steroids (androstenedione, testosterone, and estradiol) than do subordinates (Davies et al. 2016). Here, in 95 wild meerkats, we evaluated associations between constitutive immunity (bacteria killing ability and hemolytic-complement activity) and sex-steroid concentrations. Males, that show no rank-related differences in sex-steroid concentrations, also showed no rank-related differences in immunocompetence. Compared to subordinate females, however, dominant females were immunocompromised. Because both androstenedione and testosterone, but not estradiol, were strong predictors of constitutive immunity in females, androgens may mediate the health disparity in this female-dominant species. Supported by NSF IOS-1021633.
