Author: Ceri Watkins, Co-Founder of Dung beetle UK Mapping Project
Species: Dung beetles
Why is farmland important for these species?
There are approximately 60 species of dung beetle in the UK. They are not the ‘ball rollers’ seen in warmer countries and on TV, instead they live inside the dung pile (dwellers) or in the soil beneath it (tunnellers). Livestock grazing provides much of the dung required for the survival of these beetles, although other animals such deer and badgers also contribute. Some species are rather specialised and require exacting conditions. For example, Volinus sticticus prefers horse or sheep dung in the shade and Onthophagus joannae is a sun loving beetle that favours sheep dung on light soils. Others are less fussy and have few specific requirements.
It is possible to find dung beetles at work all year round. Several species are winter active, although the vast majority are found in the spring, summer and autumn. Given the right conditions, dung beetles can decimate a pile of horse poo or a cow pat in just a couple of days.
Volinus sticticus (c) Katherine Child
Onthophagus joannae (c) Katherine Child
How do dung beetles benefit farms?
Dung beetles provide a wide range of ecosystem services that help to maintain healthy pastures and soils. These include the most obvious, the consumption of dung thereby removing it from the fields thus reducing pasture fouling, but also some that you may not have considered. As the beetles tunnel down through the soil, burying the dung for breeding purposes, essential nutrients are recycled within the soil profile. This improves grass growth and provides a direct benefit to grazing animals. The larger species such as the Minotaur beetle (Typhaeus typhoeus) can tunnel a metre or more, this action breaks up the ground and improves drainage, especially useful on clay soils.
In addition, dung beetles also reduce nuisance fly populations by transporting phoretic mites that eat fly eggs and help control intestinal parasites by reducing dung suitability for worm larvae. The beetles are also an important food source for many other farmland favourites such as bats and birds.
Onthophagus similis with phoretic mites (c) Ceri Watkins
Continuity of the dung supply and diversity of habitat are key factors in supporting a diverse range of dung beetle species on the farm. If possible, maintain some outdoor grazing year-round, even if only a few animals. Planting a group of trees and grazing within them will provide variety of forage and shelter for livestock and support the shade loving dung beetles too.
Broad spectrum livestock wormers such as avermectin are detrimental to beneficial dung invertebrates. These chemicals are excreted in the dung for many weeks after treatment and a range of lethal and sub-lethal effects occur depending on the concentration. Such effects include slowing beetle larvae development, reducing the size attained at adulthood and reduced breeding capacity.
Cutting down the use of chemicals on the farm with a sustainable worm control policy that includes monitoring with faecal egg counts will help. Treating animals only when necessary will save money and also slow the rate of anthelmintic resistance. As a natural alternative in a rotational system, consider using herbal leys. Sainfoin, birdsfoot trefoil and chicory all have anthelmintic properties. The latter has been shown to reduce worm burden in sheep by as much as 40%. In permanent grasslands, mixing up cattle and sheep grazing works by reducing the stocking density of the parasite host - cattle and sheep worms are different species.
Supporting dung beetles on your farm not only helps keep pasture and livestock healthy, it also represents good economic sense. It has been estimated that dung beetles save the UK cattle industry £367 million per annum through the provision of ecosystem services (Beynon et al., 2015). So, it really does pay to look after these useful little creatures.