Intraspecific evolution of Canarian Euchloe (Lepidoptera: Pieridae) butterflies, based on mtDNA sequences

Abstract

The Canary archipielago is formed by seven islands and some islets, roughly linearized and with ages increasing from east to west: Lanzarote, Fuerteventura, Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro. This archipelago has become a model scenario for many studies of species formation and evolution (Juan et al., 2000) due to its ecological variety and its proximity to the African Continent. Evolutionary studies concerning butterflies have made important contributions to the field of evolution and biogeography (Braby et al., 2006). However, many problems arise when only morphological variation is used to infer historical colonization, lineages and origins. The use of molecular markers has proved to be very helpful in resolving these biogeographic questions (Avise, 2004), but few studies have been carried out in the Canary Islands (Brunton and Hurst, 1998; Weingartner et al., 2006). The genus Euchloe Hubner, 1819, comprises a set of about 25 Palaearctic and Nearctic species grouped into two proposed subgenera (Euchloe HBN and Elphinstonia Klots groups; Back et al., 2006). The Euchloe subgenera groups aproximately 17 species widely distributed in North Africa, the Iberian peninsula and the Canary Islands. The species Euchloe belemia in particular comprises at least six subspecies. The subspecies Euchloe belemia belemia and desertorum occur in the Iberian peninsula and North–West Africa, respectively. The subspecies Euchloe belemia palaestinensis and moslemi occur in Arabia, and the subspecies Euchloe belemia hesperidum and eversi occur in the Canary Island, particularly in Fuerteventura (hesperidum), Gran Canaria and Tenerife (eversi), although in Gran Canaria the population is very scarce, possibly due to the forest fires in the last decade. The assignment of the described species to either subgenera, Elphinstonia or Euchloe, has been incomplete and partially incorrect due principally to the lack of phylogenetic studies, so current tax-