Origin and dispersal of Potamophylax cingulatus (Trichoptera: Limnephilidae) in Iceland

Abstract

Summary The earliest record of Potamophylax cingulatus in Iceland is from east Iceland in 1959. In the 1970s, the distribution of the species in Iceland was restricted to the east and north‐east. In a survey conducted from 2004 to 2008, P. cingulatus was found all over Iceland, except in the central highlands. The speed of dispersal has thus been around 7.3 km per year. To study the origin of the population in Iceland, we assessed variation of the COI gene of the mtDNA of P. cingulatus in Iceland and from the neighbouring countries. Almost no variation was detected in the Icelandic population, and the flies were closely related to flies from the Faroe Islands, reflecting its most likely route of colonisation. A wider survey of the variation within Europe showed a clear structure of three major lineages: an Atlantic or western lineage from Spain to Norway, a central or eastern lineage (Czech Republic and Austria) and a southern group from south‐east France. The phylogeographical patterns within Europe point to at least three refugia during the glacial periods of the Pleistocene.