Genetic identification of mammalian meal source in dung beetle gut contents

Coprophagous dung beetles are a numerically and functionally important group. Their obligatory use of mammalian dung has broad ecological implications, including providing economically and epidemiologically relevant ecosystem services. Beetle-mammal ecological networks are critically important in determining the resilience of dung beetle communities and the supply of beetle-mediated ecosystem functions. However, our understanding of dung beetle trophic networks remains incomplete. Here we report on a pilot study to evaluate the effectiveness of DNA-based analyses in identifying the source of dung beetle meals. Using beetles collected from dung piles of known provenance, we hypothesized that molecular analysis of gut content would correctly identify the mammal host, and that beetle body size would increase the odds of successful detection of mammalian DNA. We analyzed 90 specimens belonging to six beetle species. Most samples yielded mtDNA sequences from the expected mammalian species, suggesting that these methods can be an efficient tool for the investigation of dung beetle diet.