Bumblebee numbers could tumble as Britain’s heatwaves intensify

Bumblebee numbers may fall as they struggle to cope with the increasing intensity of recent heatwaves in Britain.

One study suggested that fuzzy bugs become pale in hot weather and are better suited to Britain’s historically cooler, more temperate climate.

The UK has faced three consecutive heatwaves this year; Temperatures are regularly rising above 30C and new warm weather is on the way.

Data from the Bumblebee Conservation Trust showed a significant decline in the population of Britain’s most common bees in years when heatwaves were more intense.

Bumblebee Conservation Trust’s chief scientific officer, Dr. Richard Comont said bumblebees are increasingly at risk every year due to the country’s changing climate.

He said: “They’ve got a big furry coat on them, they’ve got huge flight muscles that generate a lot of heat when they’re flying. You can imagine them beating their flight muscles two and a half thousand times a minute when they’re flying – that produces a lot of heat.”

“They’re actually very good at keeping heat in, but they’re not very good at keeping heat out. So when the air temperature gets too hot, they have a hard time getting that heat out fast enough.”

As a result of a series of heat waves in 2022, species such as the red-tailed and buff-tailed bumblebee, as well as the common comb bumblebee, declined by 20 percent, 25 percent and 35 percent.

Dr Comont explained that bees in the UK have an upper temperature limit of around 30C and when temperatures rise above this they can struggle to find food because they cannot shed their body heat quickly enough.

He added: “In more severe heatwaves, you get that kind of heat at 10am rather than noon, and there’s a bigger window where they can’t forage for food.”

Heatwaves can worsen existing threats to bumblebees, such as habitat and food loss due to drought.

Talking about 2026 so far, Dr. Comont remains optimistic and says there are a few species that are doing “pretty well” after a good start to the year, but the rest of the year’s results remain uncertain after this summer’s heatwave.

“I hope it picks up a little more this year because the spring has been pretty good. But we’re already in such a hot and dry period that I suspect those numbers are already starting to drop. That comes with the caveat that we’re not really getting extremely hot days, at least not too many, it’s a long kind of chronic heat wave, and that means drought is probably going to be an issue.”

“We only had the numbers up to the end of June, but we’re seeing that the bees are actually doing quite well at the moment because we’ve had a pretty good spring, because we’ve had a warm winter and so a lot of the bees have been able to get an early start.

“March in particular has been exceptionally good. The buff-tailed bumblebee in particular broke the record for the best March this year, which dates back to 2008, and a few other bees are doing really well because we had good conditions. I was a little worried about what this month would look like, but we don’t have that data yet. Generally speaking, this year has been really good for the bees so far.”