Forest and field abundance of Scarab beetles (Coleoptera: Scarabaeidae) in the São Donato Biological Reserve, Rio Grande do Sul, Brazil

Abstract

The objective of this work was to compare the species richness, abundance and diversity of Scarabaeidae beetles in two types of habitats (field and forest), and to assess whether their seasonal variation is related to climatic variables. This study was conducted in the São Donato Biological Reserve, Rio Grande do Sul state, Brazil (Pampa biome). Beetles were collected using pitfall traps between January 2012 and January 2013. A total of 125 individuals were collected, of which six genera and 11 species from four subfamilies of Scarabaeidae were identified. 54 individuals of five species were collected from the field, and 71 individuals of eight species were collected from the forest. The most abundant species were Ataenius picinus Harold, 1868, Canthon lividus Blanchard, 1845 and Leucothyreus flavipes Eschscholtz, 1822, which together accounted for 86.4% of all individuals captured. The highest total number of individuals was collected in summer (78), and the highest number of species was collected in spring (9). Differences in environmental structure (and associated climate) and food resource availability may be decisive and limiting factors for beetle occurrence in forest versus field areas, as various species were restricted to a specific habitat type or season.