Ecological And Evolutionary Aspects Of Mimicry In Melitaeine Butterflies

Mimicry is one of the best examples of adaptive evolution. The phenomenon was first identified by Bates in 1862 to describe butterflies in the Amazon. Since that time numerous additional mimicry systems have been described across a diverse range of taxa. Here we characterize a mimicry system involving variable phenotypes. Using a generalized avian predator, black female Chlosyne palla is shown to be a Female-limited polymorphic mimic (FPM) of black Euphydryas chalcedona, whereas both species are palatable in the red form. We also demonstrate that a related species, C. hoffmanni, is palatable to a generalized avian predator. We use a long-term dataset to test theories pertaining to the flight time and abundance of Batesian and FPM systems with emphasis on checkerspots in California, E. chalcedona and C. palla. We found evidence of negative frequency-dependent selection in Batesian mimics, but not in FPM systems. We also found evidence for the model-first emergence hypothesis in Batesian, but not FPM, systems. In an effort to understand the evolution of mimicry in this system we produced a Bayesian time-calibrated phylogeny of the Nymphalid butterfly tribe Melitaeini. The resulting phylogenetic hypothesis is compared to previously published hypotheses of this tribe. The phylogeny presented here is the most complete hypothesis to date, incorporating more species and more genetic information than any previous version.