The lack of influence of exogenous testosterone on male parental behavior in a neotropical frog ( Eleutherodactylus): A field experiment

Abstract

Males of the Puerto Rican frog Eleutherodactylus coqui exhibit prolonged parental care (nest attendance and defense) of direct-developing eggs in nonaquatic nest sites. Earlier work showed that plasma androgen levels are significantly lower in males caring for eggs than in noncaring, calling males. In this study, we investigated the effects of elevated plasma androgens on parental care behavior by implanting either testosterone (T) or placebo (P) pellets in parental males brooding eggs in the field. Plasma androgen levels, assessed 4 days after pellet implantation, were six times higher in T males than in P males. Despite this increase, T males exhibited no changes in nest fidelity or brooding behavior. The results indicate that lower androgen levels, at least those corresponding to a decline in T during parental care, are not necessary to maintain parental behavior in this tropical frog.