This year has seen record numbers of wasps. Common wasps (Vespula vulgaris) or ‘jaspers’ as they are known to country folk, have appeared in plague proportions. Last year, if I remember rightly, there were very few but the same certainly can’t be said this summer!
Apparently there are 9,000 species of wasps in the UK alone and 100,000 identified world-wide. The vast majority are tiny, parasitic and solitary and, in England, the common wasp is the only one that really bothers us. If one is annoying you the best thing to do is stay calm. An angry wasp stings to defend itself and also releases a pheromone attracting other wasps to come to its aid.
Unlike bees, wasps do not store food so cannot survive the winter and they all die, with the exception of a few young fertilised queens. These individually seek out somewhere to hibernate then emerge in spring and set about building walnut sized nests in which each lays around twenty eggs. These hatch out into larvae which she feeds. By May they are mature and become workers. The queen then focuses her attention on laying more and more eggs which in due course also become workers. They expand the nest and feed the ever increasing number of larvae. Surprisingly, wasps do serve a useful purpose at this stage of their life cycle. The larvae need meat and while the workers don’t eat meat themselves they catch insects, aphids, ants and caterpillars to feed them on.
This process continues until August when the queen ceases to lay eggs, apart from a special few to produce males and future queens. She no longer releases the pheromone which stimulates her workers to work. With no larvae to provide meat for they switch to searching for sweet, sugary substances to feed themselves and can also be seen drinking at bird baths and fish ponds. Come the cold weather they, the original queen and the males all die. Only the hibernating, mated queens survive.
Nests may be built in sheds, garages, bird boxes, wall cavities or a hole in the ground. Their location can often be discovered by studying the route wasps take. They are made out of seasoned or dead wood which has been chewed up and mixed with saliva to form a grey, paper-like substance. Beware, nests may be up to 40cms in diameter and contain 10,000 wasps but they really are works of art and well worth taking a close look at once they’ve been abandoned.
Professional pest controllers and local councils charge to dispose of active nests. Alternatively proprietary brands of powder or foam aerosols are available over the counter which, if used as instructed, can be effective. However, great care must be taken. Protective clothing should be worn and the nest only treated in the cool of late evening or early morning when the wasps are least active. If powder is used it should be put in place using a spoon tied to a long stick.