Title

Investigating trait evolution in the wild: How multiple selection pressures shape animal behaviour and life history

Abstract

How does trait evolution work in the wild? Conditions are messy and complex in nature. Multiple selection pressures are at work, including food abundance, predation risk, mate competition and availability of breeding sites. These selection pressures are not constant but can vary dramatically over space and time. How do traits evolve under such conditions? I present two lines of research from our group that address this broad question. First, I describe our long-term field studies of a wild lizard, examining the evolution of traits related to attracting mates and deterring competitors. I describe how sexual selection, together with predation, acts differently on males and females. This results in sex differences in sexually selected traits. Second, I examine the unusually variable egg-laying behaviour of female Aedes mosquitoes. We are begining to discover that, rather than arising from a lack of selection, this variation appears to result from a complex strategy through which females balance diverse and variable risks. Studying multiple selective factors in the wild is challenging, but may be necessary if we are to understand the full range of traits that we see in nature.