Caddisfly (Trichoptera) larvae of the Opa River basin, south-western Nigeria

Abstract

Caddisflies in the streams of the Opa River catchment basin in Ile-Ife, south-western Nigeria, were surveyed, documenting nine genera in six families. Hydropsychidae is the most speciose family, with three genera, and has the highest number of individuals in the total fauna. Streams in the area with appreciable disturbance were devoid of caddisflies. This was attributed to the impact of human activities although other factors such as substrate availability and stream size could also apply. The large number of hydropsychid caddisflies at one sampling station was attributed to the presence of submerged beds of Fontinalis (Bryophyta) in that area, which is usually associated with the occurrence of that taxon. Efforts should be made to create favourable conditions in the streams and rivers of this catchment to avoid possible extermination of caddisflies and to foster an increase in species richness.