Meeting Abstract

46.1  Tuesday, Jan. 5  Testosterone and melanin face mask coloration in female northern cardinals (Cardinalis cardinalis) JAWOR, Jodie M.*; WINTERS, Caitlin P.; University of Southern Mississippi, Hattiesburg; University of Southern Mississippi, Hattiesburg jodie.jawor@usm.edu

Melanin-based feather coloration (e.g., black, reddish-brown, or dark brown colors) has been a focus of research interest in sexual selection in terms of the use of melanin ornaments in male dominance relationships. In a variety of species, individuals with either larger or darker melanin-based face-masks, breast stripes, head stripes, etc. are socially dominant. Findings from manipulative studies suggest that testosterone (T) during fall molt may impact male melanin-based coloration, thus providing a potential link between dominance, aggression, and melanin ornament expression. However, not as much focus has been placed on the use of melanin ornaments in females and whether this ornament type may be influenced by T in females. In this research we maintained 20 northern cardinals, Cardinalis cardinalis (15 females, 5 males), in captivity through molt and collected plasma samples for T levels every second day until molt was completed. Female face mask expression prior to and after molt was compared to average, minimum, and maximum T levels. We found that average T over the period of molt co-varied with the darkness of the melanin-based face mask; females with darker masks had higher average T during molt. Face mask size and color have been previously shown to co-vary with aggression during conspecific interactions in cardinals and T has recently been shown to increase during aggressive intrasexual interactions between females. Potentially, females with higher T during molt may produce an ornament that reliably displays information on future behavior that is also influenced by T.