Predation by Chironomid (Diptera) larvae on oligochaetes

Eight species of chironomid larvae fed on oligochaetes in laboratory cultures. Setae of 5 species of oligochaetes were observed in gut contents from 13 species of chironomid larvae collected from four different habitats. Abundance of oligochaetes occurring with chironomids in polluted waters seemed to be influenced by predation. Aquatic oligochaetes and chironomid larvae are among the most commonly encountered invertebrates in the freshwater benthos. The relationships of aquatic oligochaetes with other organisms, particularly predator-prey interactions, have been little studied (Brinkhurst and Jamieson 1971). That chironomid larvae of the Tanypodinae are predatory is well known; Miall (1895) reported predation by these animals on Tubifex sp. in laboratory cultures. The larvae of the subfamily 1 Part of a thesis submitted for the M.S. degree at Auburn University. Chironominae have generally been considered ito be herbivorous and detritus feeders; however, larvae of species of Cryptochironomus have been reported to feed on oligochaetes (Wirth and Stone 1956; Darby 1962). I have found that larvae of both the above subfamilies of chironomids feed on oligochaetes. Although the incidence of predation by the Chironominae was not as great as that of the Tanypodinae, certain individuals of the former group fed readily on an available oligochaete. I wish to thank J. S. Dendy for his guidance and R. 0. Brinkhurst for his comments and advice concerning this