Heat perfect for 'plague' of wasps

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IN THE mild winter and hot summer the common wasp, Vespula vulgaris, has flourished. Its numbers are well above the norm, and you could be forgiven for thinking that a plague of biblical proportions is imminent, writes Martin Walker.

Wasps, says Carl Clee, honorary curator of aculeate hymenoptera (stinging insects) at the Liverpool Museum, "are extremely efficient predators". Vespula vulgaris is omnivorous, eating grubs, caterpillars and insects as well as leaves, fruit, nectar and sugar. It lives in well-ordered communities in which each individual plays a clearly defined role.

As with other insects of the order hymenoptera (insects with four transparent wings) this society is presided over by a queen, who rules supreme, even dictating the sex of the wasps produced in her nest. She does this by keeping sperm separate from the unfertilised eggs.

Some eggs develop into male wasps (drones), whose only purpose is to mate; others into female workers who leave the nest to forage for food and defend the nest against attack. At the end of each summer, new queens are produced by selective feeding - only these survive the winter.

The sting is carried by female workers alone. "Wasps do not sting indiscriminately, but respond only to what they see as being threatening," said Mr Clee.