Dung Beetles – the Farmers’ Friends
By Sally-Ann Spence – Entomologist and farmer
I wonder how many of you go out and look through piles of your cattle dung? If you did however, you would discover a myriad of small life from flies to beetles, spiders to earthworms and tiny springtails. If you look closely at the beetles you would notice most of them are moving quite fast. This is because they are predators, hunters looking for live prey. They could be rove beetles (Staphylinids), long and slim ideal for running along tunnels or clown beetles (Histerids) built like armoured tanks with powerful jaws. There are even several species of water beetles (Hydrophilids) who specialise in living in wet dung rather than ponds. If you find a slower moving beetle, that might even play dead when you pick it up, then chances are you have found a dung beetle. Dung beetles eat the dung and as a result they are responsible for a variety of ecosystem services that ultimately help us.
Dwellers, Tunnellers and Rollers
We have approximately 60 species of dung beetles in the UK. These can be split into two groups: dwellers, those that live in the dung and tunnellers who live under it. There is a third group, which we do not have in the UK, rollers, who make balls of dung and roll them away. The reason we do not have them in this country is the climate and the lack of competition for dung. In hot climates dung beetles make dung balls and roll them away from the competition, they then bury them to consume in peace or to lay their egg on. One egg per ball of dung hopefully guarantees a large enough store of food for the hatched larvae to be able to grow and pupate into another adult dung beetle. In tropical rainforests, where there is even more competition for dung, dung beetles can be found clinging onto the fur around monkey anus’s until they defecate. The dung beetles then grab the faeces as it falls and use the dung as food or to use for their own eggs before anything else gets the chance to steal it away.
Dung beetles are considered key ecosystem service providers where there is dung present. They deliver many benefits to farmers including increased soil nutrients and general nutrient recycling. They improve the soil structure by increasing aeration and drainage which in turn increases rainwater filtration through the soil leading to a reduced run-off of rainfall. Dung beetles also indirectly reduce pest flies and gastrointestinal parasites by carrying mites between dung pats; these mites eat fly egg and larval eating mites. Finally, dung beetles are incredibly important in keeping pastures green and healthy for livestock by reducing pasture fouling and increasing soil nutrition, especially in the absence of non-organic artificial fertilisers.
Dung beetles are a vital part of the pastureland biodiversity as both the beetles, their pupae and their larvae are an important part of food webs supporting many insectivorous birds and omnivorous mammals.
Different dung beetle species live in or under different dung in different stages of decomposition on different soils at different altitudes at different times of the year. You can find different species where the dung has fallen on grass to where it has fallen on bare soil, such as around gateways and water troughs. Some species prefer the dung in shaded areas, such as under trees and hedges, compared to that in the full sun out in the centre of an open field. As there are dung beetle species active all year round, they require a continual supply of dung, and to have a mixture of species they need a diversity of habitats where that dung falls.
Dung quality is important too. Native breed livestock on unimproved permanent pasture with a large diversity of herbage is ideal. To be a great micro habitat the dung needs to have depth and form. A splatter is too shallow to escape predators, it is liable to dry quickly making it an unsuitable food source and the beetles can even drown in it. With the right conditions, and with several dung beetle species present, a cow pat can be broken down in just a couple of days.
They Need Your Help
It is not all good news in our pastures though, as research is already showing an alarming trend in dung beetle species rarity and even recording species extinction. The three main reasons behind this are considered to be the use of anthelmintics (especially in wormers), soil disturbance and the disappearance of livestock from historic pastures due to a change in farming practices.
There are several things farmers can do to help these incredible beetles, so in turn helping their livestock.
Anthelmintics have a major impact on the breeding cycle of dung beetles so the ‘smarter’ you can be in their use the more the dung beetles’ benefit, along with your pocket. Be selective on your parasite treatments and consider the natural parasite burden of your breeding stock. Get to know ‘your’ worm burden by getting faecal worm egg counts done before treating. If possible, treat individually animals and weigh before dosing to not use too much chemical. If you house your livestock then try to treat them a few weeks before letting them out onto pasture, to keep the toxin away from the beetles. In short:
Livestock welfare comes first, so if you need to treat for parasites then treat, if you are unsure have a discussion with your vet and remember to mention our friends the dung beetles.
Keeping livestock out all year is important, even if only a couple of animals, as there are less winter active species, but it is vital that the dung is there for any early emergences of adults in the warm spring weather spikes.
These are just some of the steps that are available to you to try and support dung beetles, who will in turn do their best to support your livestock and you, a true friend of the farmer.
For more information on dung beetles, and what you can do to help visit www.dungbeetlesforfarmers.co.uk
Dung Bettles for Farmers is an information website set up by entomologists, farmers and a vet. The team gives up their time and expertise to promote dung beetles as well inform farmers and vets to the huge benefits they perform to the grazing ecosystem.