García-Rosales, A., R. Cruz-Elizalde, A. Ramírez-Bautista & V. Mata-Silva

Feeding ecology of two populations of Sceloporus minor (Squamata: Phrynosomatidae) inhabiting contrasting environments in central Mexico. pp. 103-114.

Abstract. Food resources have a significant effect on many characteristics of living organisms, such as growth, reproduction, and tissue repair, among others. These resources, however, can vary among localities and seasons of the year. In this study, we examined the feeding ecology of the lizard Sceloporus minor from two localities (La Manzana and El Enzuelado, Hidalgo) with contrasting environments in central Mexico. The analysis of the stomach contents revealed an omnivorous diet, composed by 14 prey categories. Comparing the two study sites, lizards from La Manzana consumed 13 prey categories, and lizards from El Enzuelado consumed 11 categories of prey. In both localities, adult coleopterans, hymenopterans, orthopterans, and plant matter showed the highest values of food importance. By sex, males and females from La Manzana consumed 11 prey categories each, whereas in El Enzuelado males consumed eight prey categories and females consumed 10 prey categories. By season, lizards consumed a higher number of prey categories in the dry season than in the wet season for both La Manzana and El Enzuelado. Niche breadth values were low by population, sex, and season; however, the overlapping values were high. The volume of stomach contents was not correlated with male and female SVL in either population. However, the volume of stomach content in females varied significantly through the three stages of the reproductive cycle, vitellogenesis, embryonic development, and post-reproductive period. Results showed that the diet of both populations of S. minor is omnivore, consuming mainly insects and plant material. Low diet amplitude and a high overlap between populations, sexes, and seasons of the year, indicated that these populations have a high preference for specific prey items. This study expands the knowledge of the feeding ecology of this species and, consequently, of their populations. Additionally, it provides specific information regarding the effect of food on female reproductive traits throughout the year.

Key words. Food resources, lizards, niche breadth, omnivorous diet, diet overlap, populations.