Thesis Abstract – Spagna (1995)

Spagna, Joseph C. (1995)
Adaptivity of Banding Patterns in the California Mountain Kingsnake, Lampropeltis zonata.
Bachelor of Arts, Pitzer College, Biology.
Advisor: Dan Guthrie.

The brightly colored banding patterns shared by venomous coral snakes and nonvenomous kingsnakes of the New World have long been considered an example of a vertebrate mimicry system. The conspicuous patterns have been shown to confer the advantage of predator aversion upon Costa Rican snakes, where the venomous and nonvenomous types are sympatric. The California Mountain Kingsnake (L. zonata) is a local relative of the Costa Rican mimics, with a similar coloration pattern. There are no poisonous coral snakes in California to provide the model for a traditional mimicry system. Due to this lack of a model, I proposed that a combination of effects, including warning coloration and cryptic effects, accounts for the survival of the conspicuous Californian kingsnakes. Two studies were carried out, one in the laboratory and one in the field, using clay models to determine the effects of coloration on visibility and overall rate of interference, respectively. The experiments showed a significant difference in visibility on one background, but did not provide evidence for a fitness difference between banded and single-color patterns. The studies provide a basis for further inquiry into untested aspects of the California Mountain Kingsnake’s survival, including extensions and refinements of those carried out here, as well as test of possible ecological factors, such as partial refuges, not examined here.