Nature's muck spreaders
This week I explore the fascinating world of dung beetles and return to the topic of slugs
Last week, I listened to a fascinating episode of the podcast Accidental Gods in which Faith Tilleray interviewed Claire Whittle aka the Regen Vet. As well as being a vet, Claire is an expert in dung beetles. I have long been intrigued by these insects, so her podcast spurred me on to delve in a bit deeper to these amazing creatures.
I’m sure many of you may have see amazing footage of African dung beetles racing over to a fresh pat of dung and then rolling the valuable material into their tunnels to feed their larvae. I was lucky to have a chance to look for dung beetles in Botswana – the guide was somewhat surprised when I said I wanted to look for elephant dung rather than search for leopards and lions, so I spent a fascinating few hours rooting around dung and I came home with photos of all sorts of fungi living on the dung, which I used in one of my children’s books on recycling.
Rollers, tunnellers and dwellers
There are thousands of species of dung beetle and they are found in most habitats and on all the continents, apart from Antarctica. But to make matters confusing, they are not neatly classified into the same family. So for simplification, biologists tend to group them according to lifestyle: rollers, tunnellers and dwellers.
Most people will probably be surprised to learn that there are around 60 species of dung beetle in the UK, living inside or under dung as dwellers or tunnellers. Some are ultra-fussy and only like dung from a particular animal, while others take any dung they can find. You are likley to have seen the dor beetle Geotrupes stercorarius, a black beetle with a vibrant violet blue tinge to its underside and legs. It reaches around a couple of centimetres in length and is found on pasture where it creates a nesting tunnel under the dung which it then lines with dung to feed its larvae.
Another is the minotaur beetle, Typhaeus typhoeus. The males have impressive projecting horns on either side of their head – miniature versions of a stag beetle. They are found on sandy grassland where they feed mostly on rabbit droppings.
Muck spreaders
Dung beetles provide essential ecosystem services, their key role being to recycle nutrients and remove dung so there is less fouling of the pasture. The larger beetles tunnel deep into the soil under the pat and this helps drainage, especially on clay soils. The minotaur beetle for example, can create burrows more than one metre deep.
They are part of an essential food chain based on the nutrients locked up in dung. Flies lay their eggs in fresh dung and this attracts predators – spiders, swallows and bats that feast on the flies and then crows come down to forage for larger insects in the pat.
Another role of our dung beetles is the transport of phoretic mites that feed on fly eggs. The mites can’t fly, so they hitch a lift and it’s not unusual for a dung beetle to be home to a colony of mites, hence the name the lousy watchman.
Not all pats are the same
So much affects the quality of the pat. Dung beetles evolved alongside livestock that were fed grass. Claire has studied how the diet of the cow affects the quality of the dung, for example, whether the cows are fed hay from a rye grass monoculture or a species-rich meadow. Cows that are corn fed often produce a runny poo which is not so desirable.
Several years ago, I was horrified to learn that giving wormers to animals results in traces of the chemical ending up their poo, especially the toxic ivermectin group. They persist in the dung for weeks and not surprisingly this has negative consequences on animals like dung beetles. The presence of the chemical effectively kills the pat, so it sits on the surface, devoid of life, breaking down slowly and fouling the pasture. I think of the many horse owners who religiously worm their horses and then they spend hours every week clearing up the pasture. Perhaps they would be better to faecal test their horses to see whether a wormer is actually needed before using it? Then they may find that the job of clearing the pasture is done for free by the dung beetles. They would also end up with a healthier pasture.
I will also mention the fact that dogs are at risk too if they eat any dung that has wormer in it, especially those breeds that are sensitive to ivermectins, the collies and Old English sheepdogs for example. These are horrible chemicals and we use them too freely on our animals – livestock and pets alike.
Claire recounted many tales but one stood out. Australia. Before the settlers arrived, the largest mammals were marsupials and the dung beetles were adapted to marsupial droppings. Then the settlers introduced cows and soon there were vast herds of cows on the grasslands and lots of cow pats. But without suitable dung beetles, the pats hung around and attracted loads of flies, which thrived on this new food source! So back in the 1960s the Australian Dung Beetle Project was set up to introduce dung beetles to solve the fly problem, which was successful. Now here’s a statistic for you: There are 28 million cows in Australia and each cow produces on average 12 cow pats a day. So that’s millions of tonnes of dung a year – no wonder they needed dung beetles!
Dung beetles and climate change
We know now that these insects are helping to reduce greenhouse gas emissions from grasslands by around 12% - something that few people talk about when they bash livestock farming. But Claire is worried that scientists are tinkering with the diet and genetics of cattle to reduce methane emissions. Will that backfire? There is a chance that changing the diet of cow to reduce flatulence may affect the quality of the dung and then we lose the dung beetles… its such a finely balanced ecosystem.
Learning more
I am keen to go on a dung beetle course – I don’t have many animals on the farm anymore – a couple of ancient kune kunes, some poultry, but there are lots of rabbits, deer and badgers, so hopefully there are a fair few dung beetles around.
Do find time to listen to the podcast. It’s very farming focussed at the start, but they start discussing dung beetles in the last 30 minutes
Do we get dung beetles in gardens?
I had to look this up. Well, there are more than 4,000 beetles species in the UK, and surprisingly over half of these can be found in London!
We get chafer beetles in the garden, which are in the same family and they are dung feeders. Many gardeners don’t welcome the chafer grub because of the damage to lawns, but only a few chafer species cause the damage. The majority of the chafer beetles seen in gardens are found in compost heaps.
But what about the dung beetles that feed on the dung of rabbits and deer. Gardens with these animals, especially those with woodand glades may see them.
But I couldn’t find much info so would love to know if anybody can shed more light. It was more worrying to find so such information about getting rid of beetles.
Publication day
Its publication day for my latest book tomorrow 21 March. Its competitively priced at £14.71 on that well known outlet, and just £13.97 for Kindle. If you do buy a copy can I ask that you leave a review. They are important to author sales - apparently, the algorithm doesn’t care what the review says or the stars - just that there is a review - madness! But that’s the game we authors have to play.
And finally slugs
I wrote a lot on slugs last week and two days later I was horrified to find that my kalette plants were covered in slugs - more than 40 a plant. They weren’t consuming it fortunately, but sheltered amongst its leaves. Not a pleasant find and something new to me.
Talks and Workshops
Workshop 24 March An Introduction to growing fruit and vegetables with Sally at her garden at Empire Farm in Somerset - couple of places available
Workshop 5 April Growing polytunnel and undercover edibles over winter with Kim from her garden in West Wales
Talk 15 April Sally is speaking at Fagus at Nailsea, Somerset
Workshop 19 April Get climate change savvy GYO course with Kim from her garden in West Wales
Talk 11 May Sally is speaking at the FarmED Literary Festival - the venue is brilliant and the speakers awesome
I did not know we had dung beetles in the UK, it feels silly to say that out loud now but of course we must do. I love how they are split into groups related to their lifestyle, dwellers sound great. Thank you for a very interesting piece!