The evolutionary significance of regional integumentary loss in island geckos: a complement to caudal autotomy

Regional integumentary loss is a predator escape strategy employed by representatives of at least 10 genera of gekkonid lizards in several evolutionary lineages. It involves the loss of patches of the skin and is dependent on the bilayering of the dermis and the inherent weakness of the outer layers of the skin. Such loss engenders problems of radiation exposure, osmoregulation and immunological integrity. The vast majority of geckos exhibiting the trait live on islands. The subjugation mode employed by island predators, such as primates and snakes, may be a significant factor in driving selection for integumentary loss. Skin weakness may be expected to evolve when the chief predators use grasping or pinning in the early stages of subjugation, rather than an initial killing bite or strike. Skin-loss is a phenomenon similar to caudal autotomy, but differs primarily in that it is effective only with respect to some types of predators and only as a last line of defense, after predator contact with the prey body has been made.