Swimming of Planktonic Cyclops Species (Copepoda, Crustacea): Pattern, Movements and Their Control

Abstract

The zooplankton of lakes and seas consists for the most part of copepods, some species grazing phytoplankton and some living as carnivores, hunting other copepods. Animals of the order Cyclopoida are between 0.05 and 0.3 ern long and show a very distinct jerky (hop and sink) swimming pattern, using an average of one powerstroke per second. This gives them a mean speed of O. 1 to 0.5 ern/sec so that their Reynolds number ranges from 1 to 50. Storch (1929) filmed the sequence of movements of the four ventrally situated pairs of legs during a power stroke and found a 4-3 -2 -1 metachronica1 pattern. One stroke of all the legs together brings them back to the original position (ventral, front), supposedly leaving the animal with a forward velocity component.