Beetles - Focus (September)

On a number of evenings recently, I have come across a Lesser Stag Beetle plodding along our patio or climbing the wall of the house. Black and about 2-3 cm long, it’s a big beetle and was easy to spot. It is hard to know where it is heading and why, given that beetles have wings, it wasn’t flying but I was pleased to see them. We have a large rotting ash stump at the top of the garden and, as we see these beetles every year, I assume that it is using that stump in which to breed. Although this species lacks the spectacular mandibles of the Stag Beetle, they can still give you a bit of a nip if you try to pick them up. Another impressive beetle we regularly get in the garden in spring is the Violet Oil Beetle, which clambers around in the sunshine amongst emerging stems of grass and Ox Eye Daisies. Our wildflower bank hosts solitary bees which the Oil Beetle larvae parasitise. Another often seen beetle is the Orange Soldier Beetle, which one can sometime see in good numbers on the heads of umbellifers or strikingly contrasting with the bright yellow of Ragwort flowers.

However, apart from ladybirds I rarely see many other beetles in the garden. This is surprising as there are more than 4000 species found in the UK, with a wide range of habitat and food preferences. Indeed globally, of all the animals known to science, one in four of them is a beetle. Beetles as a group are known as coleoptera which means “sheath winged”. This is because they have stiffened forewings which function as wing cases to protect the rear wings when not flying.

Beetles are an important and beneficial part of any ecosystem. As they move around on flowers, they aid pollination. Most have chewing mouthparts but have differing tastes in food. Ladybirds chomp aphids, Stag Beetles eat rotting wood, the striking orange and black Sexton Beetle prefer decaying flesh, and some species will take on big slugs to eat. Some predatory beetles will feed on other beetles and their larvae. And without dung beetles recycling waste into the soil, we would be inundated with the excreta of all our wildlife and stock. Beetles are found in virtually every habitat, but while some are common throughout the country, others are so specialised that they are only found in a few locations.

This summer seems to have provided particularly favourable conditions for at least one of the more than 100 species of Flea Beetle in the UK, so called because they have big hind legs they use to jump when disturbed. In our garden they have smothered the nasturtiums in such numbers that, when passing, you could hear a rustle as they all leapt off the leaves. They left nothing for the white butterfly caterpillars to feed on this year. Meanwhile on the allotment, it’s been a brassica massacre, the tiny adult Flea Beetles appearing in their thousands, eating holes in plants leaves and stunting growth. Just one more of the unusual natural events prompted by this extraordinary summer.

​Andrew Graham