The biology of Brachycentrus subnubilus Curtis (Trichoptera) in the River Frome, Dorset

The period between oviposition and the start of hatching varied from about 17 weeks at 3°C to about 1 week at 22°C, and the length of the hatching period varied from about 34 days at 3°C to about 3 days at 22°C. Regression equations are provided to estimate the lengths of both periods at all temperatures between 3°C and 22°C.

Data are given on the biology of several species of Trichoptera in the Metolius River, Oregon, based on drift and benthos samples. Twenty-seven species were collected. Species of Limnephilidae, Brachycentridae, Hydroptilidae, and Lepidostomatidae were important drift components. The Metolius River is extremely productive, with a mean density of larval Trichoptera of 7400 per square meter in benthos samples and a maximum of 5000 per 24 hours in drift-trap samples. Different species varied in their tendency to drift, in the age class distribution in the drift, and in diel periodicity. Drift-trap collecting is shown to be a useful method of studying aspects of behavior such as the dispersal of larvae and the emergence of pupae.