The influence of predation risk on within-patch foraging decisions of cryptic animals

摘要: Cryptic animals must trade-off foraging benefits with predation risk costs, because movements reduce their crypsis, thus exposing them to predators. A forager's estimate of the associated various options will vary its probability that a predator is present ("@"). In this thesis, @ varied examine influence on behavior cryptic animals. I show experimentally response tidepool sculpins (Oligocom maculosus) conspecific skin extract (elevated #) depends level crypsis. subjects (on sand substrate), for whom movement risky relative immobility, rate more than non-cryptic ones white relatively safe (i.e., immobility). generate predictions about $dynamics, prey capture distances, and diet selectivity mathematically. Bayesian-updating model specifies how information influences #, predicts following detection, generally decays non-zero asymptote, at rates dependent an animal's vigilance crypticity. dynamic programming (DPM), state variables representing energy (the dynamics which are specified by updating model), determines maximum distances maximize surviving period. The decrease increasing # state, @on increase state. brine shrimp (Artemia sp.) shorter without, supporting prediction #. DPM also relationship between profitability danger changes @. An experiment juvenile coho salmon (Oncorhynchus kisutch) failed demonstrate effect. Finally, coupling output forward simulation model, effects arrival probability, forager crypticity, food availability examined.