On warm spring evenings I often hear these large beetles whirling above the trees and shrubs at the bottom of my back garden before I actually see them. Also called the ‘May Bug’ or ‘May Beetle’, it is a large beetle which has a black head and pronotum, which are covered in short pale hairs. It has a pointed abdomen which looks like it may contain a sting, but it doesn’t and it is completely harmless. The wing cases are reddish-brown in colour and are ribbed, and are covered in fine grey hairs which make them appear dustied. They have large fan-like antennae which are longer in the males. They can grow up to 30mm long
The C-shaped larvae feed on the roots of a wide range of plants, including cereal crops, living in the ground for up to 5 years. Often called ‘Rook Worms’, they are fat and white grubs which are 40 to 50mm long. The adults feed on the leaves and flowers of many deciduous trees and shrubs, and other plants, but rarely do much harm.
After mating the females lay between 20 to 30 eggs 20cm deep in soft soil. The eggs hatch after around 21 days where the larvae will remain up to 5 years feeding on roots. They pupate in autumn and overwinter in this state until the following May or June when the adults emerge. The adults live up to 8 weeks.
Seen May to June, and found in woodland, farmland, hedgerows and gardens.Cockchafers are often attracted to light at night, and are often heard making a loud buzzing noise, which is the sound their wings make during flight. They are fairly clumsy fliers, and often bump into things, especially lighted windows. They are commonly seen at dusk circling trees, sometimes swarming in large numbers. Common and widespread in southern Britain, rarer further north.
Photograph of Common Cockchafer (Melolontha melolontha) taken May 2014, rear garden , Staffordshire. © Pete Hillman 2014. Camera used Nikon D3200, with Sigma 105mm macro lens.