Diversity and Seasonality of Aquatic Beetles (Coleoptera) in Three Localities of the State of Tlaxcala, Central Mexico

Abstract

Aquatic beetle diversity was compared between three study sites in the state of Tlaxcala, central Mexico: Stream 1 (San Ambrosio), stream 2 (San Tadeo), and a lake (Acuitlapilco). Sampling took place bimonthly during an annual cycle. A total of 2968 specimens were obtained, which were grouped into twenty three species, fifteen genera, and six families (Elmidae, Dryopidae, Dytiscidae, Gyrinidae, Haliplidae, and Hydrophilidae). Stream 2 showed the highest values of abundance (1570 individuals), while stream 1 had the highest richness (18 species). Abundance values showed two peaks each in rainy and dry seasons. The proportion of rare and dominant species was similar in all study sites. Based on species accumulation curves, the maximum estimated number of species has not been achieved in either of the three sites. Regarding alpha diversity (effective number of species), stream 1 presented the highest zero-order diversity estimated with 18.5 species. Regarding beta diversity, lotic systems (streams 1 and 2) presented a similarity of 75%. Finally, regarding the trophic structure of the adult aquatic beetle community, herbivores, predators, and decomposers were most representative in this study. Based on our results, Tlaxcala probably holds a significant diversity of aquatic beetles. This appears to indicate that species composition in geographic areas, regardless of their relatively small size, is worth documenting and, of course, preserving.