Food web of lizard species in a land-bridge island from Western Mexico

Island ecosystems provide valuable opportunities to explore some aspects associated with resource partitioning. While some ecological studies have suggested that island populations could keep a narrow dietary niche due to limited food sources, recent studies challenge this long-held belief for insular lizards. Herein, we evaluated the trophic web of the lizard community from María Cleofas Island in the Gulf of California, Western Mexico. We quantified the inter-individual diet variation for each lizard species, compared prey diversity between species, and analyzed any potential variations across different years. Our research revealed a wide variety of arthropods within the stomach contents of the lizards, regardless of their foraging strategy and habitat use. Our results also showed the inclusion of prey items that have not been previously reported in studies focusing on mainland-island populations. For example, we observed Anolis nebulosus predating cockroaches, hemipterans, and isopods. We observed differences in prey groups among lizard species, highlighting the broader niche of Anolis nebulosus, Phyllodactylus cleofasensis, and Aspidoscelis communis, as well as the narrowest trophic niche of Ctenosaura pectinata. Our research on the lizard community of María Cleofas Island has not only demonstrated the wide dietary diversity among species but has also expanded our understanding of trophic relationships in island ecosystems, with important implications for ecological studies.