Several new species of wasp have arrived in Britain with our warming weather, and their larger relative the hornet, once confined to the extreme south, has spread across England.
But how is our common wasp faring? Most queen wasps still do not survive the winter. However, it is not cold that will have killed them, but spiders or other predators.
Soon warmer days will bring the remainder out of hibernation. They will first look for nectar to give them strength to start building their nests. The timing of their emergence is hazardous because if they wake too early they might die of starvation through lack of spring flowers.
Partly because overwintering for each year’s crop of new queens is so tricky, wasp numbers vary enormously from year to year. Researchers in Britain and New Zealand have been trying to find out which factors are most important in their survival. After 39 years of continuous records at Rothamsted in Hertfordshire the conclusion is that warm, dry springs favour successful wasp years.
This trend is more noticeable since the 1990s when a general increase in wasps has been linked to climate change and warmer springs. However, that does not solve all the puzzles. A lot of wasps in one year inevitably mean far fewer the next, although the cause is not clear.
This left the researchers unable to predict wasp numbers three or four years in advance because there was no recognisable pattern over a period of years. The only general conclusion is that as the weather gets warmer it provides more favourable conditions for wasps, and we are likely to see more of them.
