Trophic preference of southern African dung beetles (Scarabaeoidea: Scarabaeinae and Aphodiinae) and its influence on bioindicator surveys

Abstract

AbstractEnvironmental assessments using bioindicators gain value if the interpretability of the indicator used is high, and it is clear how survey methods affect survey comparisons. Because dung beetles are favoured as bioindicators, we studied the trophic preference of a southern African beetle community and its potential effects on surveys of beetle diversity using manual sampling of droppings and pitfall traps baited with carnivore, ruminant or nonruminant dung. Manual sampling showed no significant differences between dung types in either dung beetles abundance or species richness. Generalised linear mixed models of total and endocoprid abundances, species richness and Real Shannon index of trap samples showed higher dung beetle diversity associated with ruminant than with nonruminant dung, which in turn was significantly preferred over carnivore dung. Hide beetles (248 Troginae specimens) were attracted almost exclusively to carnivore dung. Paracoprid abundance was comparable between ruminant and nonruminant dung. IndVal analysis showed that, of a total of 47 species, six preferred ruminant dung and only one preferred nonruminant dung. These results imply that different dung beetle species may be used as ecological indicators, depending on their natural history, and that the survey method and the dung type used to survey will influence such assessment results.