This summer, the United Kingdom has experienced an unusually low number of wasps, a development experts attribute to extreme heat and variable weather conditions affecting their populations. The decline in wasp numbers has raised concerns about potential ecological consequences, particularly regarding the control of other insect pests.

Seirian Sumner, a professor of behavioural ecology at University College London, explained that this year’s combination of record-high temperatures and inconsistent weather during spring—characterized by both severe heat and periods of cold, damp, and chilly nights—may have created challenging conditions for queen wasps. Each spring, a single queen emerges from hibernation to start a nest and raise the first generation of workers. However, if a queen dies or abandons her nest during this critical phase, the colony cannot establish, preventing the development of the several thousand workers that typically inhabit a healthy colony by August.

The record-breaking heat this summer, which saw temperatures reach 35°C in May, June, and July for the first time on record, is believed to have been more severe than in the previous warm year of 2025, when wasp populations were abundant. "This time last year, the media was filled with reports of 'plagues of wasps,'" Professor Sumner noted. "Now, even professional pest controllers report fewer requests for nest removal."

Wasps play a significant ecological role as pest controllers, feeding on flies, aphids, caterpillars, and other insects. Their scarcity may lead to an increase in these pest populations later in the season. Professor Sumner emphasized this concern, highlighting that wasps are also important pollinators and decomposers, contributing to ecosystem health beyond pest control.

The UK hosts about 9,000 species of wasps, with the common wasp and German wasp being the most frequently observed late in the summer. Despite the current low numbers, it remains uncertain whether wasp populations will recover within this year’s remaining months.

In light of their diminished presence, Professor Sumner advised those encountering wasps to consider providing assistance. Wasps may struggle to find adequate protein to feed their larvae, and the scarcity of flowers offering nectar could leave adult wasps in need of sugary sustenance.

The situation underscores the complex impacts that shifting weather patterns and climate conditions can have on insect populations and the ecosystems they support. Monitoring will continue to determine how wasp numbers evolve going forward and what wider effects may emerge as a result.