Tachysphex the grasshopper hunting wasp

Field Paintings

I have spent many hours over the last week sat beside a small piece of bare ground on Bovey Heath. This tiny patch of habitat is alive with insect activity on hot days. There are two Heath Potter wasps which use the clay soil to build their nests in the heather and gorse nearby and the mining bee Anthophora bimaculata males often settle on the quarry to warm up before whizzing around the nearby bramble blossom looking for females. The insect which has fascinated me most this week is the grasshopper hunting wasp Tachysphex pompiliformis. I had only seen this wasp with prey once before on the heath so was delighted to find a few females excavating their burrows in the gravelly clay soil and provisioning them with meadow grasshoppers.

First the female wasp runs around the quarry looking for a suitable site to dig her burrow, after several false starts she excavates a tunnel a few centimetres long. During the process she often moves small stones which are much heavier than her.

Then she disappears off in to the undergrowth before suddenly appearing at the edge of the quarry with a meadow grasshopper much larger than herself. The prey looks far too heavy for her to be able to move but she does so with remarkable speed by whirring her wings and dragging it in small jumps across the bare ground. She parks the grasshopper outside the burrow entrance then enters her burrow and pulls the prey down head first.

Underground she will lay an egg on the grasshopper, which she has paralysed with her sting, before backfilling the burrow. On one occasion I watched a wasp open up a burrow which had already been provisioned, probably by another wasp, she disappeared underground for a few minutes before backfilling the burrow. The was probably a female destroying the egg of the wasp who collected the grasshopper and laying her own egg instead.

Watch video of the wasp in action here.

John Walters

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