Dung beetle community response to vegetation type and season in an arid zone of the Mexican Plateau

Faunistical and ecological studies are lacking on dung beetles in the xerophytic scrublands at Villa de Cos, Zacatecas, of the Mexican Plateau Province. This study analyzed the effect of season and vegetation type on community structure. Pitfall traps baited with human dung were sampled at six sites on three dates (early rainy season, dog days, and late rainy season). In total, 4,040 beetles in 17 species were trapped. Vegetation type and sampling season affected average dung beetle abundance, species richness, and Simpson diversity index. Scrublands had more abundance and richness but least diversity than grasslands. Abundance diminished during dog days but richness increased during this season and the rains after it. Diversity had an inverse pattern with more during early rains than during the dog days or late rains. The community structure was determined by microhabitats for nesting provided by the combination of vegetation type and soil compaction. Telecoprids like Canthon humectus (Say) were dominant as predicted for Mexican arid zones; paracoprids were present in deeper soils and endocoprids in shallower soils. Abundance increased during periods of rainfall and diminished during dog days, which increased richness. This change because of vegetation and season could indicate a strategy to reduce interspecific competition by partial partitioning of the ecological niche. This was the first faunistical and ecological work and provided the first dung beetle records for the municipality.