Le partage des ressources alimentaires entre les espèces de lézards du désert de Mapimi, Mexique

Abstract

The diet of several sympatric species of lizards has been studied in the Mapimi desert, Durango, Mexico, in order to elucidate the ways in which resource partitioning is achieved. Despite the optional specialization of the three Cnemidophorus species (termite eaters) and of Phrynosoma modestum (an ant eater), all these lizards are mostly opportunistic feeders ; their diets are highly diversified and largely overlapping. The larger lizards, which feed upon both large and small prey species, should exert a strong competitive pressure upon smaller lizards which are limited to smaller prey. However, small lizards avoid such a competition either by having a specialized diet (e.g. Phrynosoma modestum) or by living in certain microhabitats (e.g. Cnemidophorus inornatus which is confined to Hilaria mutica communities) . In such an ecosystem, resource partitioning among sympatric lizard species is therefore mostly achieved through microhabitat preferences, and also through different feeding strategies (e.g. the «sit-and-wait» technique versus the «widely foraging» technique).