The ecological role of invertebrate dung decomposers in southern African agricultural systems

Degradation of the dung from livestock grazers is a key ecosystem service and contributes to agricultural productivity and food security. By burying dung, dung beetles and flies integrate nutrients into the soil, making it available to the wider soil invertebrate community. Without this about 80% of the nitrogen in faeces remaining on the pasture surface would be lost. The timely decay of plant and animal material is essential to the carbon and nitrogen cycles and soil fertility. However, many of the insecticidal treatments used extensively to treat livestock against parasites and vector borne disease in Africa are excreted in the faeces largely unmetabolised and the residues continue to exert a powerful and long-lasting insecticidal effect, killing the insects that are responsible for the process of dung decomposition and recycling. The specific aim of this visit will be to extend previous collaborations with BUIST and visit the University of Pretoria to undertake discussions with local southern Africa dung beetle specialists. Strategies which mitigate the impacts of insecticide and anti-parasiticide use on insect decomposers will be considered and more ecologically sensitive management approaches evaluated.