Meeting Abstract
Clinging and climbing ability can confer fitness advantages through ability to traverse obstacles, access food resources, and shelter from ground-dwelling predators or unfavorable climatic conditions. Many species of plethodontid salamanders have demonstrated obligate or facultative arboreality and scansoriality; in the absence of claws or specialized adhesive toe pads, attachment to smooth surfaces is attributable to either suction in web-footed species or the adhesive properties of mucus on ventral body surfaces. Plethodontid salamanders show significant variation between species in maximum clinging performance. The ratio of body mass to functional adhesive surface area is predicted to play a large role in determining clinging performance. If surface area scales isometrically with body mass, low performance in large-bodied species may result. Significantly higher clinging performance in large species despite low surface area to body mass ratio would suggest species-specific attachment specialization. We measured the functional adhesive surface area of attachment used during clinging on a smooth acrylic surface in semi-aquatic, terrestrial, troglodytic, and scansorial species of plethodontid salamanders. We also measured scaling of functional adhesive surface area within two species, Plethodon metcalfi and Desmognathus quadramaculatus, across a range of body sizes. Maintenance of high performance at high attachment angles in some large species is attributable to high surface area to body mass ratio achieved either behaviorally or morphologically. Within species, performance decreases with increasing body mass. Significant differences in scaling of clinging performance between Desmognathus and Plethodon suggest variation in the adhesive properties of the mucus coatings on the two species.
