Britain may be facing an increase in fly populations this summer due to an unusually low number of wasps, according to scientists.
Seirian Sumner, a professor of Behavioural Ecology at University College London, has observed a significant decrease in wasp activity across the UK this summer. She attributes this decline primarily to the unseasonably hot and dry spring, which created challenging conditions for wasp queens attempting to establish new colonies after hibernation. The initial phase of establishing a nest and raising the first generation of workers is critical, and extreme weather events during this period can be detrimental to the queen and the potential colony.
Historically, spring in the UK has presented varied weather patterns. However, this year's spring was characterized by extreme heat interspersed with cold, damp days and unseasonably chilly nights. Such climatic instability may have led to queens abandoning their nests or succumbing to the harsh conditions, thereby preventing colonies from forming.
"Their absence greatly worries me," Professor Sumner stated, emphasizing the ecological importance of wasps. "Love them or hate them, wasps are important in ecosystems as pest-controllers, pollinators and decomposers."
Wasps play a vital role in controlling populations of other insects, including flies, aphids, and caterpillars. A healthy wasp colony can consist of thousands of workers by late summer, all actively hunting insects to feed the growing brood. A reduction in wasp numbers means less predation, potentially allowing pest insect populations to surge later in the season. While wasps are not as efficient as bees, they also contribute to pollination when adult wasps feed on nectar from flowers.
Professor Sumner noted that pest control services have reported a quiet year with fewer calls to remove wasp nests, contrasting sharply with the previous year which saw numerous reports of wasp "plagues."
While it is still too early to definitively predict the long-term impact or whether wasp populations might recover later in the season, Professor Sumner advises caution and empathy towards any wasps encountered. She suggests that individuals encountering wasps might offer them a small portion of food, such as a piece of ham for protein to feed their young, or a sugary substance for their own nutrition, especially in the absence of natural food sources like flowers.
It is important to note that out of the approximately 9,000 wasp species in the UK, only a few species, such as the common wasp and German wasp, are typically responsible for stinging people or becoming a nuisance around food during late summer.