A taste for dung: food preferences of dung beetles uncovered

Abstract

Insects represent the most megadiverse animal group, having evolved a wide range of feeding strategies. Among them, dung beetles stand out for their specialization in exploiting decomposing organic matter, particularly excrements. In the Iberian Peninsula, dung beetles typically feed on various types of dung produced by large herbivorous mammals. However, when different types of dung are available, they tend to show a predilection for the most valuable one. In addition, studies using non-native dungs are lacking. Therefore, the aim of this study was to assess whether an Iberian dung beetle community may be attracted to specific dung types, including those from exotic fauna. Fieldwork was carried out in Mataelpino, a town located in Central Spain (Madrid, Spain). A total of six different dungs were used, from animal species with different feeding strategies and geographic origins: African forest buffalo, Asian elephant, brown bear, goat, fallow deer and wild boar. To determine whether dung beetles exhibit attraction for particular dung types, different statistical analyses were carried out on the data collected from field sampling. The results show that dung beetle species behave mostly as generalists, utilizing all the excrements tested. However, it was observed that there were clear preferences for certain types of excrement, notably elephant dung, which is exotic to the region. Buffalo and wild boar dungs were also highly attractive, whereas goat dung exhibited the lowest attractiveness. In conclusion, Iberian dung beetles display a generalist diet although they may exhibit attraction towards specific excrements, including those of exotic origin.