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Nonconcordance of drift and benthic activity in Baetis
Author(s) -
Wilzbach Margaret A.
Publication year - 1990
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1990.35.4.0945
Subject(s) - baetidae , benthic zone , biology , ecology , invertebrate
Simultaneous collection of stream drift and observations of epibenthic activity of Baetis nymphs (Baetidae: Ephemeroptera) from within a field enclosure were made over 24‐h periods. A fiber‐optic observation system that enabled night viewing of animals in unexposed locations supplemented observations. Drift was out of phase with epibenthic density and total number of movements of Baetis , which were greater during the day. Numbers of individuals on tops of stones were often insufficient to account for numbers in the drift. Individuals from exposed and unexposed locations fed continuously, and little difference existed in gut fullness between drifting and benthic animals. Observations do not support a hypothesis that Baetis drifts at night because it is hungry and in search of food.