Meeting Abstract

S2.2-2  Saturday, Jan. 4 11:00  Nutritional Stress and the Evolution of Sexual Ornamentation: A Life History Perspective MOREHOUSE, N.I.; University of Pittsburgh nim@pitt.edu

Nutritional stress is one of the most pervasive challenges that organisms face, with strong evolutionary leverage on all aspects of organismal life histories. Recent attention has focused on how sexual ornaments respond to nutritional manipulation. This research has provided a large number of case studies linking nutrition to sexual ornamentation. However, differences in ornament expression can result from individual variation in the capacity to acquire resources across environments and/or the strategies used to allocate those resources to ornaments versus other life history traits. Thus, the extent to which responses to nutritional stress are mediated by acquisition versus allocation is central to understanding how ornamental traits interact with other life history characters, and therefore their information value as sexual signals. Experimental attempts to separately quantify these two key aspects of resource use have been few, particularly in relation to sexual ornamentation. I first argue why attention to the difference between resource acquisition and allocation is critical to understanding the evolution of sexual traits. I then highlight recent work on the butterfly Pieris rapae to illustrate how the genetic architecture of resource use dictates specific relationships between male investment in sexual ornamentation versus other reproductive and somatic traits. In particular, I make the point that individual differences in resource acquisition may often be more important than divergence in allocation, and that the resulting phenotypic relationships have important consequences for the evolution of female choice. I conclude by pointing to experimental needs and promising avenues for further study.