Farmland Biodiversity Blog – Dung Beetles – By: Bruce Thompson

For the Festival of Farmland Biodiversity we have some guest blogs written by people involved in farming and farmland biodiversity. In our first to these blogs Bruce Thomson tells us about the importance of dung beetle

Bruce showing some of the Dung Beetles and other insect that can be found in cow pats!

We owe so much to the 40+ species of dung beetles that live in and under our dung pats in Ireland. We can put each one of these species in to one of 2 categories; “Dwellers” who live and lay their eggs in the dung pat and “Tunnellers” who dig in to the ground under the dung pat laying their eggs down in the soil. So what good can become of something born from animal waste? Well let me tell you that these guys really deserve a “pat on the back”.

When the faeces leaves the animal, it sits on top of the ground, fouling any grazable herbage under and around the pat. This pat also becomes a safe haven for nuisance flies, parasites and diseases. Until the pat has dried up and becomes colloidal with the soil, it is also leaking methane into the atmosphere. Sitting on top of the ground in a semi-liqueous state, these faeces are at a potential risk of leaching nutrients, such nutrients can contribute to an aquatic hazard and are a loss when not at the roots of herbage where they can be utilised by plants to grow.

So how do these beetles help disintegrate these pats? Well dung pats are actually mainly liquid and contrary to popular belief, the beetles don’t eat but rather drink the juices from the pat, these juices are full of nutrients. In this manner, the dwellers accelerate the drying of the pat making it more appealing to the earthworms who will bury it into the soil. Bring a spade with you some day and dig up a half disintegrated pat and check out the earthworm activity for yourself. The dwellers are the ultimate recyclers as they literally get the faeces and bury it into the soil, they can bury up to 250 times their own weight in a day, enough to make any earthworm blush!

Without sufficient base line data in Ireland, it is impossible to see accurate population trends, however we can see from the UK and other temperate climates with pastoral production systems that dung beetles are in big trouble with some species becoming extinct. They literally are “up the creek”. This highlights the importance of recording sightings.

A good diverse population of dung beetles can be a good indicator to a healthy, functioning eco-system. Not only will it indicate good animal and soil health and the assumption that other dung dwelling insects will be plentiful, but these beetles are a fantastic food source for bats, birds, badgers, foxes etc. They really are an indicator species.

On top of this they put money in pocket by saving my farm on purchasing expensive animal remedies for parasite and flies and by putting the nitrogen, phosphorus and potassium at the grass roots where it is needed. With these aspects in mind, the Australian Agricultural Department has invested millions in to capturing, breeding and releasing beetles on to agricultural land. I have taken numerous measures to increase their populations on my farm.

With farmers taking an interest in these beneficial insects and questions being asked around their population trends and how to reverse declines, I have joined up with a small diverse group to produce this website offering pragmatic impartial advice to farmers. We intend to update this website continually.

For a quick check, pick a nice “stiff” pat, 3 days old, drop it in to a bucket of water and see what floats out of it!