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Abstract

Inducible migratory behavior can be favored over fixed behavioral patterns under the changing predation regime in a lake when the risk of a contact with a predator is highly unpredictable. Since the strength of behavioral response can be adjusted to predation intensity, and behavioral defensive traits can be reversible along the predator recession, behavioral plasticity is less costly than constant maintenance of fixed defensive traits. An inducible migratory behavior can be favored if the time necessary to complete a phenotypic change is brief enough as related to the time scale of environmental change, fitness costs of producing plastic responses and of displaying such a response do not exceed the gained benefits, and reliable cues which announce the approaching danger are available to individual prey. The sensitivity to different environmental cues depends on lag time between the cue and anticipated danger in relation to the time required to display a defensive response. Whereas complicated and time consuming defenses which require deep morphological and physiological changes should be rather triggered by environmental predictors of predation onsets, unpredictable onset of predation, usually not announced by any of environmental cues, should be recognized directly, via the stimulus coming from a predator itself.