Meeting Abstract

S2.1-4  Saturday, Jan. 4 09:30  Developmental Stress, Condition, and Sexually Selected Traits in Song Sparrows MACDOUGALL-SHACKLETON, SA*; MACDOUGALL-SHACKLETON, EA; SCHMIDT, KL; KUBLI, SP; Univ Western Ontario, London, Canada smacdou2@uwo.ca

Sexual selection theory posits that ornaments and displays reflect signaler condition, which in turn is affected by both recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits are susceptible to developmental stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. Here we review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of birds from a long-term study population of song sparrows (Melospiza melodia). Field studies of free-living birds indicate that song complexity reflects the size of the song-control brain region HVC, and is correlated with body size and several immune parameters, specifically investment in protective proteins. However, song performance is not correlated to immune investment. Song complexity is correlated with the glucocorticoid stress response, and in some years this stress response predicts overwinter survival. Experimental manipulations have revealed that early life stressors impair development of HVC, but that HVC recovers in size by adulthood. These manipulations result in impaired song complexity and song learning, but not song performance. Experimental developmental stressors also affect growth, endocrine physiology, and metabolism, often in a sex-specific manner. Combined, these studies suggest that song complexity provides reliable information about early developmental experience, and about other traits that have critical developmental periods. Birdsong thus provides a multi-faceted sexually-selected trait that may be an indicator of both developmental and recent conditions.