Evidence that sex-specific signals may support mate finding and limit aggregation in the dung beetle Aphodius fossor

1. In temperate climates, dung is often colonised by several species of endocoprid (dwelling) dung beetles which use pats for feeding, shelter, and reproduction. 2. Endocoprid beetles aggregate even when offered patches (dung pats) of consistent age, size, and origin, suggesting that beetles themselves might influence the attractiveness of patches to members of their own species. Both pheromones, and physical changes to the structure of dung pats caused by colonising beetles have been suggested as mechanisms facilitating intraspecific aggregation, but neither of these hypotheses have been empirically tested. 3. Using a common European dung beetle (Aphodius fossor L.), we conducted a simple choice experiment designed to test whether (i) earlier colonisation by conspecifics could alter dung attractiveness and (ii) whether attraction was influenced by sex-specific signals. 4. We found that female beetles are repelled by dung colonised by conspecific females and are attracted to dung colonised by conspecific males. Male beetles show no evidence of attraction or repellence for dung colonised by either sex. Neither in females nor males was uncolonised dung found to be significantly more or less attractive than predicted by non-preference. 5. Our results suggest that for A. fossor male-produced signals may support mate finding in patchy environments, and that female-produced signals may serve to discourage subsequent colonisation by additional females