Dung beetle aka dumbledor aka dor beetle aka lousy watchman

 Some more pictures of the dung beetle described in today's Guardian Country Diary

' Deerness Valley, County Durham

Waiting for the clip-clop of hooves to fade away, using a polythene bag as a glove, I picked up a tennis ball-sized, steaming lump of horse manure. Checking that no one else was around – this kind of old-school natural history might seem a tad eccentric to a casual passer-by – I hurried home: I had dung beetles to feed.

 

I’d found them on the edge of a pasture and, coincidentally, had recently been reading The Sacred Beetle, Jean-Henri Fabre’s century-old account of the breeding biology of scarabs, including our native species. Could I witness what the great French naturalist first described in such fascinating detail? Fabre, meticulous observer, curious experimentalist, cautious interpreter of facts, spent years studying these ‘dealers in ordure’ whose coprophilous habits make them an agricultural asset. One study has estimated their value to the UK cattle industry, as soil improvers and recyclers of dung, at £367m per annum.

 

My captive Geotrupes stercorarius, also commonly known as dor beetles, dumbledores or lousy watchmen (they often host parasitic mites), fell out of the collecting tube onto their backs, revealing beautifully iridescent amethyst-violet undersides.

 

They have endearing parenting skills; Fabre discovered that both sexes share in tunnelling and nest preparation. They clambered over the ball of dung in the vivarium, pausing to saviour it before dropping into the grass, then digging with flattened fore-legs, forcing themselves into the soil with powerful thrusts of spiny hind limbs. Clumsy on the surface, they’re superbly equipped for subterranean life. Within a minute they had disappeared.

 

Fabre’s account describes how they dig downwards, excavate side-tunnels provisioned with what he called ‘sausages’ of ordure dragged down from the surface, then the female lays an egg in each. The next generation should emerge in autumn.

 

‘The mind, wrote Fabre, ‘is an activity, not a repository’. In some respects, naturalists live in a golden age, with so many resources available for identifying and naming what we find – AI, web sites, apps, on-line keys, social media study groups – but there’s more to natural history than compiling an inventory of biodiversity. Nothing comes close to that pleasure, first experienced in childhood, of first-hand observation, marvelling at lives of other creatures that share our planet. '

 

Here is a short YouTube video of the beetle digging its tunnel 

A dirty job, but someone has to do it....

We've found three of these dor beetles Geotrupes stercorarius blundering through the leaf litter in Backstone Bank wood in Weardale in the last week.

Dor beetles tunnel through animal dung and lay their eggs underneath, where their developing larvae live on a rich diet of faeces that's conveniently located just above their heads. It is said that adult and larva can both eat their own weight in dung everyday, which we should be thankful for: without them it might be piled high in the fields.

It seemed odd to find these in this patch of ancient woodland because there is no cow dung, which they often eat. The largest animal poo in Backstone Bank belongs to roe deer, although dog walkers' pets also make a contribution to the beetle's nutrition and child-rearing.

Dor beetles are ungainly insects and this one lost its footing, tumbled down the bank and landed, upside-down and helpless, at my feet. The iridescent blue-black colours areparticularly attractive, provided you don't dwell for too long on what it has just emerged from.

I turned it over with a twig and sent it on its way.

Dor beetles are also known as 'lousy watchmen' because they are usually infested ith mites. To see an afflicted individual that we found a couple of years ago, click here

A "lousy watchman"

We found this magnificent Dor beetle Geotrupes stercorarius when we were helping to clear an overgrown garden at Winlaton Mill near Blaydon yesterday. 

The armour on these lumbering insects is incredible - just look at that thick plate on the forehead and between the eyes, and those serrated edges to the legs; they're built like a battleship. Those clubbed antennae are unusual too. 

When we picked it up we noticed that there seemed to be something unusual going on at its rear end and tipping it on its back revealed the cause....

..... a dense cluster of parasitic mites under its tail. Most dor beetles seem to be infested with these, giving them an alternative colloquial name of the 'lousy watchman' - presumably because that are often found after dark near lights - like night watchmen.

Blue iridescence is a feature of the underside of these beetles.

Turning it on its back also induced it to open its wings ...

..... as well as exposing its tormentors. Despite its armour it has no real defence against the mites, which attach to the softer articulating tissue between the plates of its exoskeleton. Here it's trying, unsuccessfully, to dislodge them with weak movements of its hind leg. 

Dor beetles breed in chambers under cow or horse dung, dragging the dung into their burrows to feed their grubs.

It quickly righted itself and them rampaged across a gardening glove, looking mighty annoyed. The aerofoil profile of its extended elytra, that are held rigid in flight while the wings beat under them, is nicely displayed in this photo (double click for a larger image).

It looked like it might fly but never quite managed take-off, folding its wings under its elytra instead.


There's a fine picture of a dor beetle in flight on the ARKive web site - click here

For more pictures of animals infested with mites, click here , here and here .