All you need is dung

Ali J. Birkett – Lancaster University; @thatali_ecol

When I tell people I work with British dung beetles, I usually get two responses: The first is: “I didn’t know there were dung beetles in Britain”, and the second: “Why?”

The 3 types of dung beetle

Well, there are about 65 species of dung beetles in Britain. But they’re not the sort of dung beetle that you usually see in wildlife documentaries, which are often filmed in places like Africa, where there are big mammals and lots of large piles of dung. There you get what are known as “roller” dung beetles. They take a small section of the dung, roll it away, and bury it and as a food supply for their young. We don’t have that type in the UK, but we do have “tunnelers” and “dwellers”: the tunnelers take the dung just a small distance from where it’s dropped and bury it in the ground. The dwellers complete their whole life cycle within the dung-pile itself.

Dinnertime for a dung beetle

I study dung beetles because they’re really important to the ecosystems in which they live. As their name suggests they’re beetles, and they feed on dung: The adults feed on the liquid parts of the dung and the larvae feed on the more fibrous material. So when a cow or a sheep drops a dropping, the beetles fly in and land on it. The adults feed, breed, and then they lay their eggs. The tunnelers usually lay their eggs within a small ball of dung that’s buried in the ground, whereas the dwellers do everything within the dung deposit itself. So the dung beetles are essentially moving and breaking down the dung.

Imagine taking a nice Sunday stroll through a sheep field, if it weren’t for dung beetles and earthworms, you’d be knee-deep in poop!

Ali clearly isn’t up to her knees in poop

Tunneler beetles, in particular, play a major role in maintaining soil health. The tunnels they dig help to aerate the soil, breaking it up and reducing some of the compaction created by livestock and farm machinery. Both tunnelers and dwellers also actively move nutrients from the dung into the soil. And any farmer or gardener knows how important nutrients are for plant growth!

Dung beetle activity is also important for the health of the livestock because lots of parasitic flies also breed inside dung piles. The longer the dung deposit is left lying around, the more likely those flies will infect the sheep or the cattle but if the dung is broken down, they can’t breed or survive.

British dung beetles can be any colour from red or gold to black with iridescent green or purple undersides.

Dung beetles are also important as nutritious food for other animals. Some species of bird (e.g. crows) are clever and strong enough to flip over a dung deposit and pick out the beetles. Some dung beetle species are nocturnal and are a key source of food for greater horseshoe bats, which is a species of high conservation interest in Britain.

I’ve been looking at dung beetles in the British hills to see how they might be affected by changes in climate and agricultural practices. This is important because not all dung beetles are sensitive to the same types of changes, and different species have different ways of processing dung and interacting with the soil. So the presence or absence of an individual species could really matter to the system as a whole.

So in summary: without dung beetles, we’d be in deep doo-doo.

 

Find out more:

Watch a video clip: Meeting dung beetles for the first time (via twitter) 

 

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