A comparison of the algal community structure on cases of three caddisfly genera.

Abstract

This study compared the algal diversities upon the cases of three caddisfly genera, Pycnopsyche, Brachycentrus and Glossosoma. Between eight and ten larvae from each genus were removed from submerged logs, in the Maple River (a sand-bottomed, low-nutrient river) in Emmet County, Northern Lower Michigan. Algal densities, relative algal abumdance, species diversity indices, and species richness values were calculated based on information on presence and relative abundance of each algal species identified. Glossosoma had the highest density of algae (cells/cm2), followed by Brachycentrus and then Pycnopsyche. Algal samples taken from the substrates where the caddisflies were found, were used as a control. Diatoms dominated the periphyton community on the cases; diatoms are most abundant in the Maple River's benthic algal community. Trends in relative abundance of algal genera appear to be influenced by the behavior and morphology of the caddisfly, as well as algal ecology.