A wasp biologist reports Britain's wasps scarce and unusually small this summer

Absence is the hardest thing in field biology to put a number on. An empty net is consistent with fewer wasps and also with a bad fortnight of sampling. Then there is the media evidence, the thinnest in the piece: newspaper attention tracks last year's newspaper attention as much as this year's insects. The author notes that no wasp stories are running this year, where last summer, also warm, filled the airwaves with "plagues of wasps" coverage ^[3].

The Big Wasp Survey had not begun sampling when the article ran ^[5]. There is therefore no 2026 catch to set against previous years, and no percentage to attach to the gap. The author says so directly: "Admittedly, these are anecdotes not data" ^[6].

The proposed mechanism has two stages. The first is the more specific. A colony is most easily lost while its founding queen is on her own, and spring's warm, dry start released a glut of foundress queens from hibernation, each of them building the nest, laying, foraging and rearing brood alone ^[7].

Bees supply the thermal numbers. The honeybee critical thermal maximum is around 49 degrees Celsius, and UK ground surfaces passed 50 degrees this summer ^[11], at least one degree over that threshold ^[1]. Bumblebee cognition and foraging efficiency are impaired at 32 degrees ^[12], seventeen degrees below the honeybee lethal figure ^[2], and that sublethal band is where a colony quietly runs short of food. Beyond a critical thermal maximum, insects succumb to desiccation, muscle spasms and eventual stupor ^[10]. What a ground-surface reading does not tell you is the temperature inside an insulated nest, or the temperature of the air a forager flies through.

Wasps are thought to be quite resilient to extreme weather, and they are among the most successful invasive insects worldwide ^[13]. Colonies fan their wings to cool larvae, and their nests wrap the brood combs in insulating envelopes ^[14]. The waxy cuticular hydrocarbons that limit water loss change structure under heat in social wasps ^[15], and a broad diet should absorb the loss of any one food source ^[16].

The same weather carries opposite forecasts for two other groups. Butterfly Conservation is hoping 2026 could be a "bumper summer of butterflies", on the grounds that warm dry days allow uninterrupted foraging, mating and egg-laying ^[17]. The Bumblebee Conservation Trust has raised concerns that this year will worsen an existing decline as flowers wither and bees fail to forage effectively ^[18].

Of all the observations here, body size is the one to measure. An impression of size is a hypothesis, and testing it takes a measured sample and archived specimens to compare against. The remaining wasps look unusually small, which the author offers as a glimpse of how extreme heat could reshape insect populations ^[20].

Wasps work in British ecosystems as pest-controllers, pollinators and decomposers ^[19], and the country monitors them with one national survey ^[5].