Meeting Abstract
P3.60 Saturday, Jan. 5 Sprinting performance in the field by the western whiptail lizard, Aspidoscelis tigris ANDERSON, R. A.*; COLON, E.W.; Western Washington University; Western Washington University Roger.Anderson@wwu.edu
Locomotory behavior is assumed to be an integral component for meeting the ecological challenges of food acquisition, predator evasion, refugium seeking, dispersal and mate seeking in vertebrates. There have been neither comprehensive studies of locomotory capabilities for any taxon of terrestrial vertebrate, nor adequate observation and testing of locomotory capabilities in the field. Terrestrial lizards in desert scrub are useful model systems for studying locomotory adaptedness because they perform well in the lab and they can be observed easily in the field as they forage, seek mates and evade predators. The western whiptail lizard, Aspidoscelis tigris is a wide foraging species that tends to encounter ambush predators. Hence, A. tigris are expected to exhibit rapid acceleration and high sprint speeds to evade predators. Acceleration, maximum sprinting velocities, and stride lengths of adult Aspidoscelis tigris running in a raceway on natural sand and artifical substrata were documented for a single population in the Great Basin desert scrub. Lizards were slower on sand, but field velocities approximated lab velocities. Over the first meter, running lizards accelerated rapidly, with rates highest in intermediate-sized individuals. Larger A. tigris had greater stride lengths and sprint speeds than those of smaller A. tigris, but stride frequencies were similar. Other features of this Olympian lizard being studied are 1) evasion runs in the field, 2) how far the lizards can run fast, 3) how often they can repeat fast runs, 4) agility during fast runs, and 5) cost of locomotion. Integrated studies of locomotory performance will provide perspective on how ecological challenges are met by the complex of morphotype, physiotype, and behavior that comprises locomotory adaptedness.
