Notes on invertebrate drift: A pilot study

Needham (1928) first noted the ‘drift’ of aquatic insects when examining the importance of terrestrial insects as trout food. When using a fine copper wire-meshed net to collect benthos in streams near Ithaca, NY he discovered large numbers of aquatic insects present his samples. Drift attracted more attention from researchers in the 1950’s after Muller quantified drift and compared drift with benthos densities (Brittain and Eikeland 1988). Waters’ (1962) discovery of the diel periodicity of drift also helped initiate interest in insect drift. Since then, numerous papers have addressed various aspects of drift including which invertebrates drift and in what numbers, why invertebrates drift and what factors affect the drift of aquatic invertebrates.