Meeting Abstract

69.4  Monday, Jan. 6 08:45  The ups and downs of desert life: Movement, habitat structure, and biomechanics of a Namib day gecko COLLINS, CE*; RUSSELL, AP; HIGHAM, TE; University of California, Riverside; University of Calgary; University of California, Riverside clint.collins@email.ucr.edu

Successful predator evasion depends on many attributes of an animal along with the structural attributes of its natural habitat. Understanding the relationships between habitat structure, movement, morphology, and biomechanics permits contextualization of escape behavior as modulated by the physical constraints imposed on the animal. Gecko adhesion is considered an innovation permitting the exploitation of inclined and inverted surfaces. However, the deployment of adhesion can also limit locomotor speed. It is unclear whether geckos living in relatively horizontal habitats exhibit a reduced adhesive apparatus in association with alleviating these negative impacts. For four populations of Rhoptropus afer, a Namibian day gecko, we measured habitat availability, escape behavior, and morphology (macro and micro). We also estimated work and habitat-dependent stride parameters using high-speed video. Along with a relatively reduced adhesive system, R. afer relies on high speeds to escape predation. Habitats varied in substrate angularity (-65° to +76°), slope, and the occurrence of slopes ≥10° (0 – 72%). Populations differed in the percentage of escape on slopes ≥10°, which is important because such slopes may trigger deployment of the adhesive system. Although selection appears to favor a reduced adhesive system in this fast species, populations may experience varying degrees of selection depending on habitat structure. We discuss differences in toe pad area and setal dimensions between the populations. Overall, although adhesion is important for climbing, it may be unnecessary for, or even counterproductive to, the evasion of predators on relatively level surfaces. Supported by NSF IOS-1147043 and NSERC 9745-2008.