Factors affecting feeding selectivity of visual predators on the copepod Acartia tonsa: locomotion, visibility and escape responses
Buskey, E.J. (1994). Factors affecting feeding selectivity of visual predators on the copepod Acartia tonsa: locomotion, visibility and escape responses. Hydrobiologia 292-293: 447-453
In: Hydrobiologia. Springer: The Hague. ISSN 0018-8158; e-ISSN 1573-5117, more
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Keywords |
Aquatic organisms > Heterotrophic organisms > Plankton feeders Behavior > Feeding behavior Behaviour > Avoidance reactions Escapement Fauna > Aquatic organisms > Aquatic animals > Shellfish > Marine organisms > Marine crustaceans Interspecific relationships > Predation Sense functions > Vision Acartia tonsa Dana, 1849 [WoRMS]; Copepoda [WoRMS] Marine/Coastal |
Abstract |
Visual predation by fish on copepods involves prey encounter, attack and capture; during any of these processes prey selection can occur. Developmental changes in copepods, including increases in swimming speed, size and image contrast increase the encounter rate and distance at which they can be detected by predators. Copepods compensate for this increase vulnerability with age through diel vertical migration and improved escape capabilities. This study quantifies the changes in swimming speed and movement pattern with developmental stage of the copepod Acartia tonsa, using a video-computer system for motion analysis. Changes in visible size and image contrast with developmental stage were quantified under simulated natural illumination conditions using a video based image analysis system. The escape responses of the naupliar stages of the copepod Acartia tonsa were quantified in response to a stationary pipette sucking in water at a constant speed. Accurate quantification of the parameters that affect feeding selectivity of planktivorous fish will provide the basis for evaluation of their relative importance in future studies. |
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