DIET OF SYMPATRIC PATTERN CLASSES C AND E OF THE PARTHENOGENETIC WHIPTAIL LIZARD ASPIDOSCELIS TESSELATA AT SUMNER LAKE, DE BACA COUNTY, NEW MEXICO

The diploid checkered whiptail lizard, Aspidoscelis tesselata, is a parthenogenetic species that occupies semiarid habitats in the southwestern USA. It comprises several morphologically distinct pattern classes that occasionally coexist within the same geographical area. Two pattern classes, C and E, coexist on both sides of Sumner Lake and the Pecos River in Sumner Lake State Park, De Baca County, New Mexico. Individuals of pattern class C are larger than individuals of pattern class E (they also produce larger clutches and take longer to reach reproductive maturity). Herein we present analyses of the stomach contents of specimens collected at Sumner Lake to determine if these 2 pattern classes show differences in their diets. Termites made up over 70% of the prey items found in the stomachs of both pattern classes, but when analyzed by volume, the most important prey were cicadas, planthoppers, and short-horned grasshoppers for pattern class C, and short-horned grasshoppers, cicadas, long-horned grasshoppers, termites, and scarab beetles for pattern class E. Considering prey other than termites, pattern class C lizards tended to consume larger prey items than did pattern class E lizards. Aside from this size-related difference, the diet of the 2 pattern classes at Sumner Lake was similar. This lends support to the hypothesis that body size and reproductive differences between the 2 pattern classes are genetically based.