Abstract
The evolution of mimicry in similarly defended prey is well described by Müllerian mimicry theory, which predicts the convergence of warning patterns in order to gain the most protection from predators. However, despite this prediction, we can find great diversity of color patterns amongst Müllerian mimics such as Heliconius butterflies in the neotropics. Furthermore, some species have evolved the ability to maintain multiple distinct warning patterns in single populations, a phenomenon known as polymorphic mimicry. The adaptive benefit of these polymorphisms is questionable since variation from the most common warning patterns is expected to be disadvantageous as novel signals are punished by predators naive to them. In this study we use artificial butterfly models throughout Central and South America to characterize the selective pressures maintaining polymorphic mimicry inHeliconius doris. Our results highlight the complexity of positive frequency-dependent selection, the principal selective pressure driving convergence amongst Müllerian mimics, and its impacts on interspecific variation of mimetic warning coloration. We further show how this selection regime can both limit and facilitate the diversification of mimetic traits.
Keywords: Polymorphic mimicry, Müllerian mimicry, Heliconius , diversification, polymorphism.
August 5th, 2021
Dear Editor,
I am pleased to submit our manuscript entitled “Balanced polymorphisms and their divergence in a Heliconius butterfly”for consideration as an Ecology and Evolution research article.
In our manuscript, we study the selection pressures on polymorphic and divergent mimetic wing colorations of the aposematic butterfly,Heliconius doris . Using artificial model experiments, we show how wing color polymorphisms are maintained by balancing selection within populations. Further, we show that selective pressures on wing colorations are highly localized and that across large geographical scales, divergence in wing color patterns corresponds to differences in predation pressures. These results are particularly interesting asH. doris is one of few Heliconius species that display polymorphic mimicry and have not experienced a radiation of wing color patterns similar to several other Heliconius species. We discuss how the seeming paradox of polymorphic mimicry in H. doris may be maintained and impact the diversification of co-mimics. Collectively, the study establishes H. doris wing colorations as an example of polymorphic mimicry and offers insights into the selective pressures that drive the diversification of mimetic warning colorations.
We believe the ecological approach of this study and the contribution of its findings to evolutionary biology make Ecology and Evolution an ideal venue for this manuscript. We expect your readers to find its contents pertinent and useful in understanding the selective pressures behind adaptive radiations and the evolution of polymorphic mimicry.
Sincerely,