Meeting Abstract

1.8  Sunday, Jan. 4  Effects of Body Temperature and Distance to Refuge on Risk-Taking in a Lizard ANDERSON, R.A.; Western Washington University Roger.Anderson@wwu.edu

Avoidance and evasion of predators are two complementary strategies contributing to an individuals survival. Terrestrial ectothermic animals such as the heliothermic lizards are hypothesized to vary in their vulnerability to predation as a consequence of body temperature and distance to refugium. Thus, after a lizard has been chased from a basking site back to its refugium, it is expected that both body temperature and distance between refugium and basking location should interact to influence when the lizard will re-emerge and resume basking. The effects of body temperature and distance of refugium from basking site on lizard anti-predator behavior were tested in male western fence lizards, Sceloporus occidentalis. Each individual was tested in paired combinations of distance and body temperature: a) warm-near, b) cool-near, c) warm-far, and d) cool-far. Order of tests was random. A test began when a lizard was just beginning to bask or in midst of its first bout of basking for the day, whereupon it was chased to its refugium by an ersatz predator. Time until re-emergence was recorded. The re-emergence times were ranked and non-parametric comparisons for the four treatments were made within and among lizards. There were strong influences of temperature and distance between refugium and basking site. It is inferred from these results that lizards act as though they perceive vulnerability to predation inversely with body temperature and directly with distance, thus altering their behavioral strategies accordingly.