The mention of wasps brings negative images to most people’s minds: these are no more than the pests which spoil picnics, but in fact they are invaluable garden helpers . . .
Despite this, the mere sight of them on a sandwich or near a glass of wine seems to bring out the Rambo in normally placid fathers. Instantly they start to comb the garden for their nests. Once found, even the most avowed supporter of the RSPB has no compunction about wiping out thousands of tiny lives with chemicals, fire or boiling water. The excuse, of course, is that these aggressive little creatures threaten children with gruesome strangulation from swollen throats following an accidental swallowing.
Yet this reaction does these industrious creatures a grave disservice. For most of the spring and summer they are unquestionably our friends and allies. Unlike bees which manufacture their own vegetarian food from nectar, the workers from a wasp colony spend April to August on the prowl for protein.
To get a fairer impression of these brightly striped creatures, try venturing into the cabbage patch on a sunny day in high summer. Watch closely among the leaves and you will find these striking yellow and black predators harpooning and dismembering the caterpillars that are turning the leaves into green doilies. During this larvae-raising phase the colony is almost entirely carnivorous and it is only after the young have emerged that the workers begin to crave sweet things.
This is when the picnic menace rears its head, but even now the nuisance is temporary for within a matter of weeks the cooler weather causes the colony’s collapse when the queen leaves the nest to hibernate in a dry, frost-free, crevice (attics are particular favourites). She alone will survive the winter, for without her chemical commands the workers disperse aimlessly and quickly die.
A second reason for regret is that wasps live a very laudable lifestyle. They are incredibly hard working and effectively follow a ‘all for one and one for all’ philosophy. If one wasp stings an attacker or is killed, it releases a pheromone which induces aggression in the rest of the colony. Thus swatting a wasp near its nest can trigger a mass response. To make matters worse for the attack, wasps have barbless stings so can sting and sting again. In contrast bees have barbed ‘harpoons’ which rip out their intestines on first use: nature’s equivalent of a suicide bomber.
Wasps are also great architects, manufacturing their own paper by chewing rotting wood and mixing the pulp with saliva. When doing this they are very particular about materials and a suitable piece of timber – such as an untreated fence post – will be ‘mined’ by a constant stream of workers. The resulting papier mache is then used to create intricate constructions that are every bit as complex as a honeycomb.
The nest starts as a small ball, barely large enough to house the queen. Here she lays her first eggs, but when the early handful of workers start to swell in numbers, so the nest grows. A big nest can finish the summer the size of a football and house 10,000 insects (although a grapefruit and 1,000 would be more usual).
This usually hangs from the eaves of a shed or branch for protection from predators. One might think a colony armed with thousands of poisoned darts would be immune from attack, but both badgers and honey buzzards are particularly fond of the grubs, fluffing up their fur or feathers to harmlessly absorb most stings.