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Water flows produced by Daphnia and Diaptomus : Implications for prey selection by mechanosensory predators
Author(s) -
Kirk Kevin L.
Publication year - 1985
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.1985.30.3.0679
Subject(s) - daphnia pulex , predation , biology , daphnia , ecology , crustacean
Calibrated hot‐wire anemometer probes with 100‐ µ m‐long sensitive elements were used to quantify the water flows produced by the swimming motions of Daphnia pulex and Diaptomus hesperus. A free‐swimming Daphnia produces aperiodic, rapidly accelerating flow pulses. As Diaptomus swims past stationary hot wires, feeding appendage movements produce slowly accelerating flows that contain a 50‐Hz oscillatory component. Data concerning the attenuation of flow speed and acceleration with distance from tethered Daphnia, together with attack distances of Chaoborus trivittatus larvae on Daphnia, were used to estimate the threshold signal amplitude necessary to release the attack behavior of the predator. Comparison of the threshold signal for attack allows active prey selection to be distinguished from passive prey selection.