MATTINGLY, W.B.*; JAYNE, B.C.; University of Cincinnati; University of Cincinnati: A field and laboratory study of the effects of perch attributes on path choice during the arboreal escape locomotion of four ecomorphs of Anolis lizards
Arboreal locomotion is constrained by the networks of perches that comprise discrete paths. Thus, we examined how the structure of a chosen path, defined by perch diameter, length, incline, and inter-perch angle, affects the ability of an organism to evade a potential threat. We quantified perch choice and escape velocity of four sympatric species of Anolis lizards (A. sagrei, A. carolinensis, A. angusticeps, and A. distichus). To assess the trade-off between maneuverability and speed, we chased lizards past branching points of trees in their natural habitat and on four standardized artificial perches in the laboratory. In the field, perches with the largest possible diameter were chosen in 82-96% of the trials for each species. Similarly, the straightest inter-perch angles were chosen in 75-91% of the trials for each species. The choice of paths based on the incline and length of the perch was more variable. Previous studies have shown that both decreased diameter and increased turning angle can decrease maximal running speeds. Two bifurcated artificial perches imposed either a 45° turn (Y-shaped) or 90° turn (T-shaped), and the two arms within each bifurcation differed in diameter. Each of the two trifurcated artificial perches had two equal-diameter side branches at 45° turn angles. However, one of these trifurcated perches had side branches with a diameter larger than that of the straight path, whereas the other had side branches smaller than that of the straight path. On the artificial perches, path choice and speeds of running were species-dependent. Supported by NSF grant IBN 99-83003.
