Experimental Support for Aposematic Coloration in the Salamander Ensatina eschscholtzii xanthoptica: Implications for Mimicry of Pacific Newts
A field experiment was conducted to test the hypothesis that the plethodontid salamander Ensatina eschscholtzii xanthoptica benefits from aposematic coloration. Under field conditions, clay models painted to resemble E. e. xanthoptica were attacked significantly less often than models lacking the supposed aposematic colors. In addition, the head region of models was attacked significantly more frequently than random, suggesting the models were perceived as prey items. These results are consistent with the hypothesis that E. e. xanthoptica is a mimic of highly toxic Pacific Newts in the genus Taricha. The significance of the E. e. xanthoptica phenotype for the ring species biogeographic scenario and future research directions are briefly discussed.Abstract
Representative attacked plasticine models. (A) Avian peck mark on an orange morph. (B) Heavily damaged orange morph, predator unknown. (C) Rodent incisor marks on the snout of a brown morph. (D) Heavily damaged head region of a brown morph, predator unknown
Comparison of the proportion of attacked body regions (head, torso, tail, and limbs) relative to the volumetric proportions of those regions. * indicates the proportion of attacks differs significantly from the proportion expected if attacks were random relative to volume (P < 0.05)
Contributor Notes
Museum of Vertebrate Zoology, 3101 Valley Life Science Building, Berkeley, California 94720–3160. Present Address: Department of Ecology and Evolutionary Biology, Earth and Marine Sciences Room, Room A316, Santa Cruz, California 95064. skuchta@biology.ucsc.edu