Common commercially available parasiticides do not cause fatal changes in the microbiome of the dung beetle Onthophagus binodis-a pilot study

Dung beetles perform vital ecosystem functions, but their survival is threatened by parasiticide use in veterinary practices. Currently, it's unclear if parasiticides directly harm dung beetles or cause damage via secondary effects on crucial microbiome components. We investigated the impact of three commercial parasiticides (P1-levamisole and oxfendazole; P2-abamectin, levamisole and oxfendazole; P3-moxidectin) on Onthophagus binodis dung beetle gut and exoskeleton microbiomes. Dung beetles were subjected to parasiticides mixed with fresh dung for 14 days, and we used 16S rRNA genes to detect bacterial diversity changes. The tested parasiticides didn't alter dung beetle gut communities, but slightly affected the exoskeleton microbiota composition. No mortality difference was observed. Onthophagus binodis microbiomes are mainly diet-influenced, and their exoskeleton is more adaptable than their gut. Our study suggests that adjustable dung beetle microbiomes aren't susceptible to parasiticides due to their innate resilience.