Wasp Style Pottery on Warm Devonshire Heathland

Nov 24, 2010
John Blatchford

Potter Wasp Nest in America - Pollinator - Creative Commons

The potter wasp makes small clay vases and fills them with paralyzed caterpillars that are eaten by the developing larva.

Only one British species of wasp makes clay pots, and at present it is only found in the south of the country. With global warming it might well move further north.

Hunting for Potter Wasps in Devon

On 7 November 2010 Lionel Kelleway travelled to heathland in Devonshire to record a BBC radio programme about the Potter Wasp. He interviewed an ecologist who has been studying the wasp for several years.

Searching for the small clay pots that the wasp builds is a time-consuming business, best achieved by finding the place where the adult female gets her clay and then following her to her building site!

Following Adult Potter Wasps

When the temperature rises to about 25 degrees the adult female wasp will search for a suitable 'quarry' where she will collect clay. This is rolled into a small ball and carried to the building site.

On arrival at the chosen spot she will deposit the ball on vegetation (usually gorse or heather) and return to the quarry for more clay.

Balls of clay are systematically added until a small (around 1cm) hollow globular structure has been formed. Additional clay draws out a narrow neck which ends in a funnel-shaped opening about 1mm across.

It takes a couple of hours to finish each vase, involving many return trips to the quarry.

The small pots are difficult to see since they are hidden in the vegetation, but the quarry is an exposed patch of sandy clay – easier to spot.

The wasp remains faithful to the quarry site, and always flies in a straight line back to the vase she is building. This means that it is possible (in theory at least) to follow her with binoculars and locate the vase.

Once completed the wasp will switch behaviours and begin hunting for small caterpillars on the gorse and heather flowers. The caterpillars are paralyzed with a sting and then stuffed into the vase through the neck.

Thirty or so caterpillars fill the vase, at which point a single egg is laid and the neck sealed up with a final blob of clay.

Potter Wasp Larvae

The egg hatches within a few days and the larva feasts on the (still living) caterpillars. After a couple of weeks the larva is fully grown and ready to pupate inside a silky cocoon inside the vase.

After passing the winter inside the vase the young chews its way out of the side of the vase and flies away to mate and repeat the cycle.

Global Warming and the Potter Wasp

Summer temperatures currently restrict the distribution of the Potter Wasp in Britain to the heathlands of the south, but as climate changes it will be able to move to suitable habitats further north.