Speciation in Pararge (Satyrinae: Nymphalidae) butterflies – North Africa is the source of ancestral populations of all Pararge species

Abstract

Abstract The genus Pararge comprises three species: P. aegeria, distributed in Europe and North Africa; P. xiphia, endemic to Madeira; and P. xiphioides, endemic to the Canary Islands. Two subspecies are recognized in P. aegeria, P. a. tircis and P. a. aegeria, distributed in northern and southern Europe, respectively. In the 1970s, P. aegeria appeared on Madeira. However, despite the status of P. aegeria as a model species in ecological studies, the evolutionary history of Pararge remains unknown. We studied the phylogenetic relationships of the three Pararge species, using the mitochondrial gene cytochrome oxidase subunit I and the nuclear gene wingless to infer modes and times of speciation. On the basis of our analyses, Pararge forms a strongly supported monophyletic group, with the DNA haplotypes of the three species also forming well‐supported monophyletic groups. We found that P. xiphia diverged first from the common ancestor a maximum of five million years ago, with P. xiphioides and P. aegeria being sister species that diverged a maximum of three million years ago. The two subspecies, P. a. tircis and P. a. aegeria, were not distinguishable on the basis of DNA haplotypes; instead, our data clearly distinguished between European specimens and those from North Africa. Madeiran P. aegeria has North African haplotypes and thus originated from there rather than from Europe. We hypothesize that the Mediterranean Sea forms a strong barrier to dispersal for Pararge butterflies, and has done so for approximately the past one million years.