Lake Texoma Caddisflies (Insecta: Trichoptera): 1. Species Present and Faunal Changes Since Impoundment

Abstract

In light-trap collections 1974-1977, 26 species of caddisflies were collected at Lake Texoma, Texas and Oklahoma. The lentic Cyrnellus fraternus (Banks), Hydroptila waubesiana Betten, and Oecetis inconspicua (Walker) numerically dominated; however, many typical lotic species were present with their larvae occupying the rocky, wave-swept margins of the lake. Greater numbers of species were collected than in earlier studies of Lake Texoma. Oecetis inconspicua adults were parasitized by the unionicolid water mite Koenikea nr wolcotti. The purpose of this study is to describe the Trichoptera or caddisfly fauna of Lake Texoma, a major impoundment in the southwestern United States. This is the first of a series of papers that will analyze the dynamics of the caddisfly community. Community is in the sense of Pielou (1975) where similar species occurring together form a loosely interrelated aggregate, a definition most similar to the term taxocene as proposed by Kownacki (1971). The caddisfly communities of lakes and reservoirs have received scant attention other than in species descriptions and faunal lists. Neave (1934), Marshall (1939), Milne (1943), and Corbet and Tjonneland (1955) analyzed flight patterns of selected lake species, while Neave (1933), Morgan (1956), and Winterbourn (1971a, 1971b) emphasized life history studies of lentic caddisflies. Considerably more literature exists on caddisflies in running waters, probably due to the relatively few species that occur in lentic waters and the difficulties in examining larval caddisfly habitats that cannot be effectively samples with grabs or cores. However, even in lake and pond environments, caddisflies are important in the diet of fishes. 1 Division of Entomology and Parasitology, University of California, Berkeley, California 94720. 2 Great Lakes Research Division, University of Michigan, Ann Arbor, Michigan 48109.