UCLA

Ithomiine butterflies form large multispecies aggregations, the formation of which is mediated by pheromones. In ithomiiine butterflies, males require secondary plant metabolites to produce pheromones but those same compounds reduce longevity. Males transfer pyrrolizidine alkaloids (PAs), exogenous plant compounds, to females during copulation. Male Greta morgane butterflies that feed longer on alkaloid-containing plants are preferred by females. Both male Mechanitis polymnia and Greta morgane butterflies fed a diet containing PAs had a shorter lifespan than males fed a diet without PAs indicating a trade-off between survival and reproduction. Despite the importance of chemical cues to mate choice, within multispecies aggregations, ithomines use visual cues initially in conspecific discrimination. However, ithomiines do rely more heavily on chemical cues in discriminating between conspecifics and heterospecific co-mimics. Although chemical cues are important in discriminating between highly visually similar mimics, not all ithomiines are equally faithful mimics. Large, aposematic species of ithomiines are less mimetically faithful while small, cryptic species are highly mimetically faithful.