Effects of canopy coverage on the immature stages of the Clouded Apollo butterfly [Parnassius mnemosyne (L.)] with observations on larval behaviour

Abstract

The immature stages of the Clouded Apollo (Parnassius mnemosyne) are assumed to be thermophilic due to the possible time limitations and variable weather conditions during their development. Thus, the degree of canopy coverage may affect habitat use by the species. We explored the spatial distribution of larvae and the development time of pupae under variable canopy coverage conditions. Larvae were most abundant in the areas exposed to direct sunlight, although the last instar larvae are mobile. Larvae also basked under litter between their foraging periods, probably to enhance digestion and the food intake rate. Moreover, pupal development was retarded by increasing canopy coverage. Prolonged pupal development and larval avoidance of Corydalis growths under tree canopies indicate that the species suffers from overgrowing and consequently increasing canopy coverage. © Entomologica Fennica. 17 June 2005.