Diet ofDinocras cephalotesandperla bipunctata(Plecoptera, Perlidae) in a South‐West Irish stream

Abstract

This study provides the first, although limited, examination of the diets of the only two Irish perlids, Dinocras cephalotes (Curtis) and Perla bipunctata (Pictet). D. cephalotes was found to include a wide range of prey items in its diet (including plant matter) but the major components (Baetis rhodani and chironomids) varied little despite considerable variation in benthic invertebrate taxa at different sites. Marked positive selection of certain prey taxa was also apparent. The diet of P. bipunctata appeared narrower but relatively low numbers of individuals were available. Although there were some differences in the composition of the diet (prey types and size) amongst three age classes of D. cephalotes there was still considerable overlap between them. An expansion in the size range of mayfly prey was also evident with increase in predator age.