Threat Factors Affecting Antipredatory Behavior in the Broad-Headed Skink (Eumeces laticeps): Repeated Approach, Change in Predator Path, and Predator's Field of View

Abstract

Antipredatory behavior can be studied from many perspectives, resulting in several distinct traditional foci in the saurological literature. Ethogrammatic efforts have produced extensive catalogs of defensive movement patterns (reviewed by Carpenter and Ferguson, 1977; Greene, 1988). A second very productive avenue has been experimental and observational study of costs, benefits, and correlates of defenses such as caudal autotomy and escape and avoidance behaviors (e.g., Shine, 1980; Hertz et al., 1982; Arnold, 1988). In some cases, predictions about effects of specific risk factors have been tested (e.g., Bulova, 1994; Burger and Gochfeld, 1990; Brafia, 1993). Antipredatory behavior has received the belated attention of optimality theorists only in recent years. Ydenberg and Dill (1986) developed a simple optimality model in which a prey's assessment of the degree of risk and the costs of fleeing determine how closely a prey allows a predator to approach before fleeing. Lima and Dill (1990) extended the optimality approach to several other components of predation risk. Clark (1994) emphasized that antipredatory decisions should be made based on consequences for long-term expected fitness, but predation risk typically has been and is here considered only in the context of probability of mortality in the immediate future.