A predator's costs of overcoming the confusion-effect of swarming prey
1984; Elsevier BV; Volume: 32; Issue: 4 Linguagem: Inglês
10.1016/s0003-3472(84)80232-8
ISSN1095-8282
Autores Tópico(s)Evolution and Genetic Dynamics
ResumoSwarms of prey are known to have a confusion effect on predators that increases with swarm density. Hungry sticklebacks (Gasterosteus aculeatus) overcome the confusion (Heller & Milinski 1979) except when frightened by a predator of their own (Milinski & Heller 1978). This study investigates whether the costs of overcoming the confusion consist of decreased attention for predators. Hungry sticklebacks detected a predator of their own less often when they fed upon a prey swarm of high density than when they attacked a low density swarm. They also overlooked the predator more frequently when they fed with a high rate than with a low one in the same high density. Thus, there is a cost of attacking high density swarms. These results confirm two necessary conditions of a model for balancing feeding rate and predation risk (Milinski & Heller 1978). The decreased attention is assumed to be due to the limited channel capacity of the nervous system in processing sensory information.
Referência(s)