FEEDING ECOLOGY OF THE LIZARD, UTA-STANSBURIANA, IN SOUTHEASTERN NEW-MEXICO

The 1st food habit assessment for the side-blotched lizard (U. stansburiana) in the shinnery oak-mesquite habitat (Quercus havardii-Prosopis glandulosa) of southeastern New Mexico is presented. Ants, beetles, true bugs, grasshoppers and spiders formed the major portion of the diet during the 4 yr study. Discriminant analyses showed the existence of annual, seasonal (monthly) and sexual variation. Variables separating years were incidental in occurrence: the major food categories occurred consistently between years. Seasonal variation was attributed to temporary changes in abundance of arthropods through the growing season. Sexual variation was pronounced in most samples and may be related to sexual size dimorphism or to behavioral differences related to defense of territories and attraction of mates. The sexual differences in diet may act to reduce intraspecific competition for food resources.