Meeting Abstract

P3.26  Wednesday, Jan. 6  The role of running in predation and antipredation by the leopard lizard, Gambelia wislizenii ANDERSON, R.A.; HOUSMAN, M.L.*; GRANT, L.J.; Western Washington University; Western Washington University; Western Washington University Roger.Anderson@wwu.edu

The long-nosed leopard lizard, Gambelia wislizenii, as a mesocarnivore, is a predator on highly mobile insects and lizards and is potential prey for raptors and snakes. We sought to determine how leopard lizards use running to evade predators and pursue prey. We expected that anti-predatory responses of Gambelia wislizenii would depend on the type of predator, the type and speed of approach, and in which microhabitat. We measured velocities and distances run by G. wislizenii when they were chased in unrestricted field conditions and in raceways by “predators.” We compared these speeds to those of G. wislizenii attempting to capture grasshoppers and model prey in unrestricted field conditions, and to the evasion speeds of the western whiptail lizards, Aspidoscelis tigris. Lizards were relatively unwary when approached by walking humans, and usually did not “evade” until approached within 1 m. Lizards chased by running humans entered larger and more foliage-laden shrubs and commonly ran along the perimeter of a shrub and out of sight before entering the shrub cover. Lizards usually sought refuge under the nearest shrub when approached by an ersatz aerial “predator.” Pursuits after grasshoppers were quadrupedal, at less than 3m/sec, and often included leaping pursuits. Evasions in raceways sometimes were bipedal, at over 4m/sec, at the speeds required to capture Aspidoscelis tigris. Western whiptails tended to be faster than G. wislizenii, but whiptails simply may have been more motivated to sprint. The only obvious predators of G. wislizenii appear to be snakes, which are relatively slow pursuers. Hence, we infer that the sprinting ability in G. wislizenii is needed for prey capture and not antipredation.