P2.200 Thursday, Jan. 5 The Effect of Surface Water and Wetting on Gecko Adhesion STARK, A.Y.*; SULLIVAN, T.W.; NIEWIAROWSKI, P.H.; The University of Akron, Integrated Bioscience; The University of Akron, Integrated Bioscience; The University of Akron, Integrated Bioscience firstname.lastname@example.org
Despite growing interest in the field, few investigations of the gecko adhesive system focus on ecologically relevant conditions in which the system is expected to function. Many adhesive pad-bearing geckos are native to tropical habitats which can be subject to sudden and extreme rainfall events. A previous report using small patches of the adhesive toe pad found that shear force generated by samples fully immersed in water did not differ from those tested in dry atmosphere. Recognizing the complexity of the adhesive system and native environmental conditions, we used shear force adhesion measurements to examine the effect of surface water and toe pad wetting in a tropical-dwelling gecko (Gekko gecko) at the whole animal scale. Using a force sensing apparatus, we tested the shear adhesive force of geckos on three substrate treatments: dry, misted with water droplets and fully immersed in water. We also investigated the effect of wetting on the adhesive toe pad by soaking the toe pads prior to testing. Wetted toe pads significantly decreased adhesion in all treatments, as did full immersion in water. Treatments with droplets of water distributed across the surface did not differ from treatments where the surface was dry, except after the gecko took multiple steps. Results indicate that the gecko adhesive system can be significantly compromised by water conditions characteristic of tropical environments. Adhesion can be maintained, however, if the toe pads remain dry and the surface is covered only with small water droplets. These findings suggest that surface water and the wetting of a gecko’s adhesive toe pads may have significant consequences on the ecology and behavior of geckos living in tropical environments.