beetle grub

The larval grub stage of the cockchafter beetle. These grubs live underground, feeding on roots for 3 to 4 years before merging as adult beetles.

Warm weather and a late spring have brought a late influx of Common Cockchafters (Melolontha melolontha) or May Bugs to the farm. These large beetles are now emerging as adult beetles after 3 to 4 years spent under the ground as white grubs that can grow up to 40mm long. They typically pupate during the summer of their third year, not unlike butterflies, before turning into their adult form,
which remains underground until summer (now!), when they finally emerge from the soil as reddish brown beetles with feathery antler-like antennae. You can use these to tell males from females, as males have seven ‘leaves’ on their antennae while females have only six.

The adult beetles feed on the leaves of trees and live for about a month, during which they mate and feed. They spend most of the day hidden among the trees, becoming active as the sun sets. At dusk they emerge noisily, buzzing around trees as they find mates and feed. They are clumsy fliers and you can often spot them crash landing into trees and each other. Once they have mated, the females will each lay between 60 and 80 eggs at the root of the trees and these eggs will hatch into grubs to start the cycle again.

Cockchafers seem particularly abundant this year and their emergence at dusk attracts many predators. Corvids such as crows and magpies wait at dusk for beetles to fall to the ground and snatch up. We’ve also spotted gulls swooping to catch them mid-air from the tops of the trees! You can find out more about these incredible beetles from Buglife and the Natural History Museum.

About Mudchute

Mudchute Park & Farm. One of the largest city farms in London with 32 acres of countryside in the middle of the Isle of Dogs.

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