A single origin of Batesian mimicry among hybridizing populations of admiral butterflies (Limenitis arthemis) rejects an evolutionary reversion to the ancestral phenotype

Abstract

Batesian mimicry is a fundamental example of adaptive phenotypic evolution driven by strong natural selection. Given the potentially dramatic impacts of selection on individual fitness, it is important to understand the conditions under which mimicry is maintained versus lost. Although much empirical and theoretical work has been devoted to the maintenance of Batesian mimicry, there are no conclusive examples of its loss in natural populations. Recently, it has been proposed that non-mimetic populations of the polytypic Limenitis arthemis species complex represent an evolutionary loss of Batesian mimicry, and a reversion to the ancestral phenotype. Here, we evaluate this conclusion using segregating amplified fragment length polymorphism markers to investigate the history and fate of mimicry among forms of the L. arthemis complex and closely related Nearctic Limenitis species. In contrast to the previous finding, our results support a single origin of mimicry within the L. arthemis complex and the retention of the ancestral white-banded form in non-mimetic populations. Our finding is based on a genome-wide sampling approach to phylogeny reconstruction that highlights the challenges associated with inferring the evolutionary relationships among recently diverged species or populations (i.e. incomplete lineage sorting, introgressive hybridization and/or selection).

Are mimics monophyletic? The necessity of phylogenetic hypothesis tests in character evolution

“…There are a variety of reasons why the results of this and prior studies [4,18] conflict with the AFLP estimate in [17], including the high potential for homoplasy among AFLP markers [23]. Additionally, the lack of applicable evolutionary models to AFLP markers and dependence on distance-based estimates of phylogeny may result in inconsistent estimates of phylogeny, especially when terminal branches are connected by relatively short internodes [23-25].…”

Sex Chromosome Mosaicism and Hybrid Speciation among Tiger Swallowtail Butterflies

“…The distance-based neighbor-joining method was used because there is no model of evolution for AFLP data [69]–[73]. AFLPs are reliable for phylogenetic reconstruction and, in fact, provide answers consistent with other sources of data in addition to being able to resolve relationships that DNA sequence data cannot [74]–[76]. Zakharov et al .…”

Mimics without models: causes and consequences of allopatry in Batesian mimicry complexes

“…In butterflies, selection acts against the introgression of mimetic alleles into a previously non-mimetic population (Limenitis a. arthemis) that has secondarily come into contact with a mimetic subspecies (L. a. astyanax; Mullen et al 2008;Savage & Mullen 2009). In snakes, range expansion by the coral snake mimic L. elapsoides has lead to selection against mimicry in allopatry and erosion of the mimetic phenotype despite ongoing gene flow from sympatry (Harper & Pfennig 2008).…”