Physiological condition drives ecological functions of two highly abundant and widespread dung beetles of South American pasturelands

Abstract Physiological condition plays a pivotal role on the interaction between individuals and the environment, consequently being related to the ecological functions that organisms provide. Body dry mass, fat and muscle mass have been proved to affect the way in which organisms behave, as the depletion of nutrients in their body affect the strategies that they present. In this study, we used two dung beetle species as a model to test the effects of individual traits and physiological condition on the ecosystem services provided by them (e.g., dung removal and soil excavation). To attain this goal, we used Dichotomius nisus and D. bos , which are widespread species that inhabit South American pasturelands and are considered important for the ecosystem functioning of these regions. The beetles were collected from introduced pastures ( Urochloa spp.) in the Brazilian Cerrado biome, and the functions performed by the individuals were evaluated in the laboratory, with females and males in buckets filled with soil. Our results show that individuals with higher amounts of fat mass performed less ecosystem functions. Furthermore, dung beetles with more muscle removed more dung and soil during their activities. Lastly, these patterns were sex and species dependent. Our study provides evidence that individual physiological condition affects ecological functions provided by dung beetles. Thus, the integration of animal condition may allow a deeper understanding of the physiological basis of the ecosystem services provided by dung beetles, as well as an individual perspective on the contribution of their ecological services.