Breadth and overlap of diet between syntopic populations of parthenogenetic aspidoscelis tesselata C and gonochoristic aspidoscelis sexlineata (squamata: Teiidae) in southeastern colorado

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Parthenogenetic Aspidoscelis tesselata (pattern class C) reaches the northern limit of its distribution in Ninemile Valley, Otero County, Colorado. Its coexistence with gonochoristic A. sexlineata permitted comparison of diets between species of different sizes, reproductive modes, and evolutionary histories. Based on numbers of prey in stomachs, A. sexlineata had a broader diet than A. tesselata C in June and July; however, breadth of diets calculated from volumes of prey were nearly the same for the two species. Despite the larger size of A. tesselata C, dietary resources were not partitioned by size and foods present exclusively in one species were rare in its diet. Overlap of diets in June could be explained by chance, but this was not true for July. Remarkably high dietary overlap in July resulted from both species taking advantage of an annual surge in abundance of grasshoppers. There was no evidence that either species was affected adversely by presence of the other. Copyright © 2011 BioOne All rights reserved.

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