Meeting Abstract

47.6  Monday, Jan. 5  Is Testosterone a Mediator for Aggressive Behavior in Female Dark-eyed Juncos? CAIN, K.E.*; AINSWOTH, K.L.; KETTERSON, E.D.; Indiana University; Indiana University; Spelman College caink@indiana.edu

Recent interest has focused on suites of correlated behaviors, termed animal personalities or behavioral syndromes, as a framework for studying behavioral variation and its effects on fitness. Because steroid hormones regulate a wide array of traits including behavior, they are a potential proximate mechanism underlying such relationships. Testosterone (T) in particular is a well-studied mediator of aggressive and reproductive behavior in male animals. In dark-eyed juncos (Junco hyemalis), a socially monogamous temperate songbird, individual variation in the degree to which males respond to stimulation of the hypothalamic-pituitary -gondal axis has been shown to co-vary with mating and parenting efforts such that high levels of response lead to more aggressive intrasexual interactions but lower provisioning of offspring. In females much less is known about natural variation in T and its role in mediating aggressive and reproductive behaviors, but experimentally elevated T has been shown to increase intrasexual aggression and decrease some parenting behaviors. However, understanding how natural variation in T in females relates to behavior is essential to predicting how selection may act. To elucidate this relationship we measured aggressive displays in free-living female juncos in two contexts, first towards a same-sex conspecific and second towards a simulated nest predator, to determine whether these behaviors are correlated with each other and with natural T profiles. If findings indicate a positive relationship between T and aggressive behaviors then this would suggest that T is an important mediator for behavioral phenotype in females as well as males and have important implications for the role of testosterone in mediating suites of correlated behaviors.