Ivermectin and Neem residues in cattle dung: Effects on dung beetle attraction and ecological functions in Brazilian pastures

Abstract

Identification of veterinary medical products carrying reduced risks to dung beetles remains a critical objective for the sustainable management of livestock parasites. Despite the essential role dung beetles play in tropical pasturelands, our understanding of the impact of alternative parasiticides, such as Neem plant extract, on dung beetle attraction and dung use is still limited. This study assessed the effects of dung from cattle exposed to Ivermectin (known to be harmful to dung beetles), Neem, and non-exposed animals (control) on dung beetle assemblage and their ecological functions (dung removal and soil bioturbation), in introduced and native pastures in the Brazilian Cerrado. Our findings revealed similar patterns of dung beetle attraction to Ivermectin, Neem, and control dung in introduced pastures. However, in native pastures, dung beetles exhibited greater attraction to dung from Ivermectin and Neem-treated cattle compared with the control. Telecoprid beetles displayed an increased attraction to Neem-treated dung in native pastures, with two species demonstrating a preference for this dung type. Ecological function performance was higher in Neem-treated dung compared with control, yet no significant difference was noted between Neem and Ivermectin in both pasture types. These results underscore the compelling attractiveness of cattle dung from Neem-treated animals to dung beetles, concurrently ensuring the preservation of dung beetle ecological functions in both pasture settings. This highlights the need for a rigorous evaluation of novel protocols incorporating natural parasiticides, which emerge as important tools in the conservation of dung beetle biodiversity and their ecological functions in tropical pasturelands.