Water temperature influences the shoaling decisions of guppies, Poecilia reticulata, under predation threat

摘要: In previous experiments, we found antipredator behaviours in female Trinidadian guppies to be influenced by water temperature. To distinguish between hypotheses suggested explain these observations, examined the effect of an increase temperature on choice shoal size individual guppies, absence and presence predation threat from a confined cichlid. At 22°C, showed no significant preference for either two sizes although other responses indicated reaction threat. 26°C, females chose with smaller group when predator was absent, but, once threatened, switched strong larger group. Variation individuals quite high all treatments, somewhat lower under warmer water, not significantly so. Our evidence indicates that behave as if they are at greater risk predation, but only Temperature-dependent increases ectothermic piscivores could result less efficient escape vulnerability because increased foraging activity. We suggest selection favouring displaying optimal balance should act more strongly higher