The distribution and life history of rakiura vernale (trichoptera: Helicopsychidae)

Abstract

The distribution of Rakiura vernale (Trichoptera: Helicopsychidae) in New Zealand suggests that it may be a glacial relict. It is known from several localities in the Stewart Island region and has also been found in the cold Waikoropupu Springs Takaka (11.7°C all year round). The morphology of the larva and its spiral case are described. The life history of the species in Waikoropupu Springs is reported and discussed. Emergence of adults takes place unusually early in spring; the flight period lasts less than four weeks. Egg laying and hatching follow closely but it is uncertain whether larval growth extends over one or two years. The final instar is present in autumn and the pupal stage lasts through winter. © 1973 Taylor & Francis Group, LLC.