Response of Copepods To Hydromechanical Stimuli

Diaptomus minutus Lilljeborg, 1889, and Cyclops scutifer Sars, 1863, detected the hydromechanical signals created by small moving spheres of sizes comparable to those of most crustacean zooplankters (~ 1 mm). The number of escapes and escape distance were affected by the size, location, and direction of movement of the spheres. Ability to detected and flee from the moving spheres was not significantly affected by ambient turbulence. The herbivorous D. minutus escaped from all hydromechanical signals. The predaceous Cyclops scutifer showed higher escape probability from large signals and occasionally recognized small signals as prey.