Bionomics of three species of glossosomatid caddis flies (Trichoptera: Glossosomatidae) in Oregon

Abstract

The life cycles of three species of caddis flies of the family Glossosomatidae, Anagapetus bernea Ross, Agapetus bifidus Denning, and Glossosoma penitum Banks, are compared based on monthly collections from Oak Creek and Berry Creek, Benton County, Oregon. Glossosoma penitum, the most abundant species, is bivoltine with overlapping summer and winter generations. Anagapetus bernea and A. bifidus are univoltine with the former being a winter-growing species, and the latter a summer species.Differences in habitat preference occurred, though all three species were collected within a single square meter. Agapetus bifidus is more common in the slower water of glides, whereas G. penitum and A. bernea occur chiefly on the riffles. Anagapetus bernea is more restricted to the headwater regions and small side branches than is G. penitum.A key is provided to distinguish larvae of the three species and the cases are illustrated.