Dietary Analysis of Lizard Species in the Dry Forest in Chamela, Mexico

This study was conducted during the dry season at the Chamela-Cuixmala Biosphere, a tropical dry forest reserve in coastal Jalisco, Mexico. Many lizard species are active during the dry season, yet little is known about their diet during this period of drought. Local lizard populations play a large role in the seasonal dry forest ecosystem. Three species of lizards were examined in this study: Sceloperus utiformis, Aspidoscelis communis, and Ameiva undulata. We expected that larger lizards would show greater diversity of stomach content when compared to smaller lizards. Pitfall arrays were used to trap the lizards, once captured stomachs were measured, then flushed with water to extract their stomach contents. We measured volume of stomach contents of approximately 20 lizards and determined the diversity and overall volume of insect and plant matter in those samples. The majority of the lizards captured during this study were juveniles, with little to no food items in their stomachs. Only one adult was captured (a Sceloporus utiformis) and it had the greatest volume and diversity of food items in its stomach. Our results suggest that few lizards are eating during the period we sampled in the dry season indicating that food resources, in addition to water, is restricted during this time of year. Our methods and study design could serve as a starting point for further studies focused on dietary analysis of lizards.