The Association of the Stream CaddisflyLasiocephala basalis (Kol.) (Trichoptera: Lepidostomatidae) with Wood

Abstract

A population of the lepidostomatid caddisfly, Lasiocephala basalis, was studied in a third order stream, the Ohe, in Hesse, Germany. L. basalis showed an intimate association with wood debris in all of its aquatic life stages. Larvae exhibited a significant preference for organic substrates such as woody debris, leaves, and submerged alder roots. Gut content analysis revealed leaf material and wood fragments as the dominant larval food items classifying larvae as facultative xylophagous. Larval dominance on wood during spring corresponded to minimal leaf litter abundance. In winter, during periods of high discharge, the most important larval habitat was the submerged alder roots at the stream margin, thus acting as flow refugia. Most pupal cases were attached to submerged logs and roots. In addition, most of the egg masses were found on these two substrates. The role of L. basalis larvae in wood degradation is discussed.