Bumblebees struggling in hot weather - what can you do to help?
The BBC's climate expert, Justin Rowlatt, explains some of the difficulties the UK's bumblebees are facing
- Published
We could see a sharp drop in the numbers of UK bumblebees as heatwaves become more frequent and intense.
That's according to data from the Bumblebee Conservation Trust, whose BeeWalk monitoring scheme has shown a decline in populations.
A reduction in numbers was seen after record-breaking heat in 2022, when the UK had three official summer heatwaves and temperatures reached 40.3C.
Three of the country's most common species, red-tailed, buff-tailed and common carder bumblebees, dropped by 20%, 25% and 35% respectively.
Read on to find out more and discover what you can do to help bumblebees...
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These numbers dropped further into autumn with colonies struggling to recover.
There were also declines in 2024 and 2025, while in 2026 parts of the UK have recently experienced three heatwaves in three months with a number of temperature records being broken.
Rising global temperatures, as a result of climate change, has put the UK on course for more frequent and intense heatwaves.
How does the heat affect bumblebees?
UK species are suited to a cooler climate, with their fat, furry bodies designed to hold heat and powerful flight muscles that warm them as they fly.
But in a heatwave their muscles generate more heat, and its harder to cool down which means they can struggle to fly without overheating.
Dr Richard Comont, the Trust's science manager, says this normally starts to happen once air temperatures reach around 28C to 32C.
If they cannot fly, they also cannot forage for food.
Red-tailed bumble bees are one of the most common UK species
The other issue for bumblebees is dwindling supplies of food due to extreme heat and drought.
Colonies depend on worker bees bringing back a steady supply of nectar and pollen during the summer, but if flowering plants dry up due to less rainfall there is less food to bring back.
If they cannot find enough food, the new bees - in the form of larvae - develop more slowly.
As a result colonies also can become weaker and there may be fewer new queen bees produced for the following year.
Nectar is for energy and pollen provides protein and other nutrients
Dr Paul Williams, a bumblebee expert at the Natural History Museum, says that for the bees it's only worth it if the amount of nectar they can get from the flowers is more than the energy used searching for food.
They cannot afford to waste energy searching dried-up flowers for nectar and pollen that is no longer there.
But scientists say that warm, sunny weather is not automatically bad for bumblebees.
Warm weather has been good for some species, particularly those with more southerly ranges.
What can you do to help bumblebees?
Conservationists say the best way to help is by planting more flowers to make it more likely bumblebees can find food, even as the climate becomes more extreme.
Dr Sarah Beynon, an insect expert in Wales, has planted meadows, willows, hedgerows, grasses and late-flowering crops to give insects food through the summer.
She has said that even a pot of native wildflowers on a doorstep or windowsill can help as "a service station" and "somewhere to rest, refuel and carry on" for bees.
Putting in a pond and some shade can also help, as flowers growing near water tend to produce nectar with more moisture in it.
Do you see many bumblebees in your outdoor spaces? Do you like to help them? Let us know in the comments...
