Country diary: Coprophagous beetles are an agricultural asset

Waiting for the clip-clop of hooves to fade away, using a plastic 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 passerby – 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 on to 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 savour it before dropping into the grass, then digging with flattened forelegs, forcing themselves into the soil with powerful thrusts of spiny hind limbs. Clumsy on the surface, they are superbly equipped for subterranean life. Within a minute they had disappeared.

Fabre’s account describes how they dig downwards and 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, websites, apps, online 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 firsthand observation, marvelling at the lives of other creatures that share our planet.

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