Testing biennialism in the butterfly Erebia palarica (Nymphalidae: Satyrinae) by mtDNA sequencing

Abstract The montane butterfly Erebia palarica has an unconfirmed life-cycle length. The genus Erebia shows variability in length of diapause depending on latitude and altitude, which may lead to allochronic differentiation. To test for biennialism and possible asynchronous differentiation, we sequenced the most variable fragments of the mitochondrial control region and the cytochrome oxidase I in forty individuals from the same population, from two consecutive years. No differentiation between cohorts could be detected and therefore the idea of a current annual cycle is supported. We conclude that a biennial cycle may never have been important in this population and we further discuss adaptive strategies this species may have used to confront colder climates.