Beetles in the British Garden
There are 3,690 species of British beetle. Their forewings have become hard (usually horny) sheaths, which meet in a straight line down the back and are lifted in flight, though not all beetles are capable of flight. The softer hind wings are folded beneath the sheaths. Their mouth parts are robust for biting and chewing.
The devil’s coach-horse or cock-tail beetle frequents rank vegetation and middens, preying largely on insects. It carries its tail turned up, like a scorpion, and appears to be dangerous but is actually harmless and even beneficial in the garden.
The violet ground beetle, about 1 in. long, is a very common garden beetle. It is black with a purplish sheen. It has a long oval body and long legs, and is a swift-runner, although it spends most of the day hiding under vegetation or in the, and generally runs across the path only when disturbed by gardening operations. It is carnivorous and destroys the harmful larvae of various moths.
The dor beetle, up to 1 in. long, is one of the heavy-weights of the British beetle world. It is black with iridescent purple and blue beneath. It lives on dung which it rolls into a ball and buries at anything up to a foot below the ground. It buries far more than it requires, and so has a beneficial effect in putting the manure where it can do most good. It flies by night, especially in late summer evenings, and if it falls on its back after colliding with something it has the greatest difficulty in righting itself.
The cockchafer beetle, up to about l in. long, is a brownish colour and flies chiefly at dusk. It is distinctly harmful to the farmer and gardener as it feeds on the leaves of trees, especially oak and chestnut. The larvae remain below ground for as long as four years, feeding on roots of grasses and damaging the roots of young trees.
Leaf beetles are a group of small and generally brightly coloured beetles whose larvae may do great harm. Species of particular menace to the gardener are the Colorado beetle, which is ladybird-shaped and yellowish-orange with black longitudinal stripes on the wing cases, and the asparagus beetle, which is longer and narrower and greenish-black with six orange spots on the wing cases.
Ladybirds, of which there are about 50 species, are often named after the number of spots they have on their backs. They are chiefly red with black spots, though the twenty-two-spot is yellow. The two-spot and the seven-spot are among the most common. Their larvae do an immense amount of good, living principally on aphids.
Wireworms, the larvae of click beetles, do a great deal of harm to crops, but birds, particularly starlings and rooks, destroy countless thousands of them. For their full description, see Garden Pests.