Comparative performance of scarab dung beetles to coprophagous beetles in dung removal and soil water runoff in a drought-prone habitat

Abstract

Beetles improving soil nutrients by burying dung is a crucial ecological process for maintaining soil health, and the tunnels created by this process improves soil infiltration and reduce soil water runoff, a vital process during droughts. This study compares the effectiveness of two native dung beetles (Scarabaeidae) with two other coprophagous beetles, a member of the Histeridae (Saprinus cupreus) and Hybosoridae (Liparochrus sp.) family. Mesocosms with a 100-gram dung pat were used in the field to produce all five treatments: a closed control mesocosm with no beetles, an open mesocosm, a closed mesocosm with coprophagous beetles, a closed mesocosm with dung beetles, and a closed mesocosm with both coprophagous and dung beetles (beetle species depended on location). After 48 hours, the dung was removed, dried, weighed, and then placed a rainfall simulator over the mesocosms to record soil water runoff. The five treatments from both locations were analysed separately. The findings show that the Saprinus cupreus and Liparochrus sp. contributed significantly to dung removal. There were significant differences in soil water runoff across the treatments, with O. consentaneus (was the best at reducing soil water runoff, with a mean reduction of 53.3%, while S. cupreus was the least effective contributing only a 28.8% mean reduction. The species O. squalidus reduced soil water runoff by 46.9%, while Liparochrus sp. reduced the mean soil water runoff by 43.9%. This investigation highlighted the need to reassess and improve our ecological management approaches including various coprophagous insect species, while understanding their collective significance in maintaining soil health.