Correlates of speed of evolution of host preference in a set of twelve populations of the butterfly Euphydryas editha

AbstractWe measured oviposition preferences and offspring performance (survival of young larvae) within several populations of the butterfly Euphydryas editha. There was a significant association between speed of preference evolution and withinpopulation diversity of preference: preference ranks were more diverse within populations where preference was evolving rapidly than within ”stable” populations that were not undergoing rapid preference evolution. Preference rank was invariant within each “stable” population, even if the population used several host species. We suggest that, at least in E. editha, intrapopulation variability of preference rank only becomes apparent during episodes of rapid diet evolution. Preference rank was highly variable among populations, and is capable of rapid evolutionary change. In each “stable” population, the rank order of oviposition preference for different plant species was adaptive, being identical with the rank order of survival of newly hatched larvae experimentally ...