Seminar Series 2004

Evolutionary consequences of Wolbachia-induced male-killing: a case study in the butterfly Hypolimnas bolina.

Sylvain Charlat (University College London and Gump Station)

Male-killing symbionts represent a potentially important driving force in the evolution of insect’s reproductive systems, due to their widespread occurrence in this group, and persistence at high prevalence. Specifically, the three following predictions can be formulated: (1) selection for resistance to the male-killing phenotype will promote rapid changes in sex determination systems, that would otherwise be costly to the host; (2) sex-ratio bias will reduce effective population size and thereby increase the importance of drift over selection within evolutionary processes; (3) male rareness will affect the intensity and direction of sexual selection, promoting rapid changes in sexually selected traits. We are currently testing these hypotheses in the butterfly Hypolimnas bolina, where variations in male-killer prevalence among populations of South Pacific and South East Asia allow a comparative approach to be used.