By means of a silhouette videotaping system we studied the frequency of movements of Chaoborus americanus and Chaoborus punctipennis when exposed to water conditioned in different ways. Four treatments were investigated: unconditioned water was used as a control; predator-conditioned water was water in which fish had been held; prey-conditioned water was water in which cladocerans had been grown; and mixed water was a mixture of predator- and prey-conditioned waters. The movement frequency of C. punctipennis significantly increased in prey water and decreased in predator water as compared to unconditioned water. The movement frequency of C. americanus significantly increased in prey-conditioned water; however, when exposed to predator-conditioned water the movement frequency was not significantly different from unconditioned water.
Berendonk, TU; OBrien, WJ. Movement response of Chaoborus to chemicals from a predator and prey. LIMNOLOGY AND OCEANOGRAPHY. Dec. 1996, 41(8): 1829-1832.