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,