The effects of sunlight, disturbance, and food availability on the distribution of chironomid larvae.

Abstract

This study investigated the effects of sunlight and disturbance on the distribution of Chironomid larvae in river systems. Artificial streams were created using water pumped from the Maple River and plastic gutters. Tiles were placed in each stream as a surface for Chironomids to colonize. Half of the streams were shaded and disturbance was imposed on some of the tiles in each stream, while the others remained undisturbed. After six weeks, the number of Chironomids present on four of the seven tiles from each stream were counted. There was no significant difference in the number of Chironomids on tiles exposed to direct sunlight and those in shaded streams. However, disturbance had a large effect on the number of Chironomids present; little or no Chironomids were found on disturbed tiles. In undisturbed areas, it appeared that Chironomids had a non-significant tendency colonize on shaded tiles. Therefore, disturbance seemed to effect Chironomid distribution while amount of sunlight had little to no effect.