Lenz, P. H. Pacific Biomedical Research Center, Univ. Hawaii at Manoa, email@example.com
Hartline, D. K. Pacific Biomedical Research Center, Univ. Hawaii at Manoa, firstname.lastname@example.org
KINEMATICS OF CALANOID ESCAPE BEHAVIOR: COMPARISON BETWEEN TWO SPECIES, UNDINULA VULGARIS AND PLEUROMAMMA XIPHIAS
Undinula vulgaris (Megacalanoidea: Calanidae) and Pleuromamma xiphias (Augaptiloidea: Metridinidae) are two widespread calanoid copepods that occupy different niches. The sub-tropical U. vulgaris occurs in nearshore surface waters. P. xiphias, a mesopelagic species, is a strong vertical migrator, spending the days below 500 m, and swimming up to the chlorophyll maximum at night. Both calanoids respond with a rapid swim to hydrodynamic disturbances. However, the kinematics of the escape differed: reaction times for U. vulgaris were 3 to 5 times shorter than for P. xiphias. Maximum forces developed during the powerstrokes ("kicks") were typically larger for U. vulgaris than P. xiphias. Both species responded to strong stimuli with multiple kicks in quick succession. U. vulgaris usually responded with 2 to 4, maximum 9 kicks, whereas P. xiphias generated long series of 20 or more kicks. These differences suggest that to escape from a potential predator, U. vulgaris, with a reaction characterized by a fast response and rapid acceleration, optimizes speed over distance, whereas P. xiphias, with a slower, more prolonged response, optimizes distance travelled. These two strategies may reflect differences in the primary predators from which these two calanoids are escaping. Supported by NSF OCE 95-21375.
Day: Thursday, Feb. 4
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