Mata, Tawny M. (2004)
Malarial Transmission to the Western Fence Lizard (Sceloporus occidentalis): The Effects of Ground Squirrel Burrow Density.
Bachelor of Arts, Pomona College, Biology.
Advisor: Stephen Adolph.
The sandfly vector (Lutzomyia spp.) for the malarial strain Plasmodium mexicanum uses ground squirrel (Spermophilus beecheyi) burrows for shelter and oviposition. A 0% infection rate in the western fence lizard (Sceloporus occidentalis) with the malarial parasite P. mexicanum was found in two adjacent lizard populations in Southern California differing in the ground squirrel burrow density within their habitats. My prediction that malarial infection would be higher in the area with greater burrow density due to increased habitat for the vector can therefore neither be supported nor denied. The negative result also prevented me from testing the effects of age, sex, and ectoparasitic load on malarial infection in S. occidentalis. Possible reasons for the negative result include a complete lack of P. mexicanum within this S. occidentalis population, false negative scoring of blood samples, and unrepresentative sampling of an infected population. The merit of each hypothesis is discussed. Future studies warrant a larger sample size and sampling for presence of the vector.