Case construction composition of (Limnephilidae) Pycnopsyche under varying water current conditions.

Abstract

This study investigated the behavior of Trichoptera larvae in constructing cases, in which several hypotheses were tested: whether case construction is independent in current speed, whether distribution of materials in the cases is independent of the materials available in the environment, and whether materials used in the construction of cases is independent of current speed. In order to test these hypotheses, the Trichoptera (Limnephilidae) Pycnopsyche were chosen. The larvae of this genus build temporary cases, rebuilding cases on a constant basis. An artificial stream system was built in order to create various current speed. The larvae were placed into these streams and given a constant amount of excess material. Over 20% of the larvae built cases throughout the duration of the study. Analysis of the amount of materials in the cases and the number of cases served to reject the hypothesis that case construction is independent of current speed. Also, we concluded that the distribution of materials in the larval cases is independent of materials available in the environment and that materials used in the cases is independent of current speed.