Cling performance and contact area in European Hydromantes (Speleomantes) salamanders


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


10-3  Sat Jan 2  Cling performance and contact area in European Hydromantes (Speleomantes) salamanders O’Donnell, MK*; Lunghi, E; Deban, SM; Brown University; Chinese Academy of Sciences; University of South Florida mary_kate_odonnell@brown.edu

Hydromantes are lungless salamanders which depend on cool temperatures and high levels of moisture to maintain the diffusion of oxygen across the skin surface. In the Mediterranean, these salamanders spend a large proportion of their life in caves, climbing on the walls and occasionally the ceiling. Clinging and climbing enable them to access deep, vertical, or elevated portions of the cave interior where suitable temperature, humidity, and nesting sites are found. Daily and seasonal variation in habitat conditions may require movement within the caves, as well as movement to more abundant food sources outside. Within the eight European Hydromantes species, three species (H. flavus, H. sarrabusensis, and H. supramontis) have been shown to exhibit positive-allometric growth in foot surface area with ontogeny, suggesting that foot area may play an important role in adult survival. However, the relationship between cling performance and foot contact area has not been explored. Here we measure maximum cling angle and contact area in five species of Hydromantes, including three with positive allometry of foot webbing. We examine how species which do or do not exhibit allometric scaling of foot surface through ontogeny differ in maximum cling performance on a smooth surface. We found that allometrically scaling foot surface area did not significantly improve cling performance. Foot surface area in some species contributes only a small fraction of the total contact area during clinging, which includes much of the ventral body surface. The use of the ventral body surface by salamanders may allow flexibility in the use of feet for adhesion during clinging, which may impact how selection acts on foot morphology.

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