Before pestering us at picnics and being a bother at barbecues in late summer, wasps act as skilled and ferocious hunters of insects with which to feed growing grubs in their nests.

Three incidents I have witnessed graphically illustrate this. A few years ago,there was a huge influx of hoverflies from the Continent. Many flew into my conservatory and became trapped. A wasp discovered the rich food source and after catching them, bit off heads, wings and legs before carrying the bodies back to its nest.

The wasp returned every ten minutes or so every day and I estimate that hundreds of hoverflies met their fate during the wasp's three weeks of activity.

Three years ago I was watching a large dragonfly emerging from my pond. Climbing up a flag iris stem it began to inflate its wings but within minutes, a wasp homed in and tried to bite off the head of the dragonfly. Failing to do so, it turned round and rapidly bit off the abdomen which fell into the water, followed shortly afterwards by the helpless dragonfly.

The first wasp was joined by another and between them, they carried away chunks of abdomen and softer parts of the thorax. An hour later little remained of the dragonfly apart from head and wings.

Then incredibly, late one June evening this summer, a wasp pounced on a pair of mating stag beetles, prised them apart and tore pieces from the vulnerable undersides (see picture). Stag beetles are heavily armoured but it was amazing to see how the wasp, small by comparison, managed to kill both beetles.

The following morning only wing cases, legs, heads and jaws were left on the lawn.