Trichoptera of a Victorian forest stream: Species composition and life histories

Abstract

The species composition and life histories of the Trichoptera of a Victorian forest stream were investigated for 21 months. Monthly samples were collected from zones of fast current in midstream over the whole study period, and also from side riffles and leaf-pack accumulations for periods of 7 and 8 months, respectively. In all, 40 species were recorded as larvae, and it is suggested that species richness is similar to comparable streams in the Northern Hemisphere. The communities of all three biotopes were dominated by Tamasia acuta (Calocidae). Information is presented on life histories of the nine most abundant species. Ethochorema turbidum (Hydrobiosidae) exhibited a non-seasonal life history, while the remaining eight species were seasonal and displayed varying degrees of synchrony. Tamasia acuta required 2-3 years to complete the life cycle, Alloerella grisea (Helicophidae) required 1-2 years, and the other six species were univoltine. Agapetus monticolus and A. kimminsi (Glossosomatidae) were temporally segregated, with the former emerging in spring and early summer and the latter in summer and autumn.