The UK's bumblebees are facing a dire situation as heatwaves take their toll. These furry insects, adapted to our cooler climate, are struggling to cope with the extreme temperatures and the resulting lack of food. As temperatures soar, their muscles overheat, and their thick coats and round bodies make cooling down a challenge. Dr. Richard Comont, the Trust's science manager, warns that once air temperatures reach around 28C to 32C, bumblebees can start to fly without overheating. If they cannot fly, they cannot forage, and they literally start dying from the inside out. The BeeWalk data from 2022, a year with three official summer heatwaves and temperatures reaching 40.3C, shows a significant drop in population numbers. The red-tailed, buff-tailed, and common carder bumblebees, three of the country's most common species, saw a 20%, 25%, and 35% decline, respectively, before continuing to struggle into autumn. The effects of the heatwave persisted, with queen numbers below average in March, April, and May 2023. However, scientists emphasize that warm, sunny weather isn't inherently bad for bumblebees. Some species, particularly those with more southerly ranges, have benefited from previous warm years. The issue lies in extreme heat and drought. Bumblebees face two challenges: overheating bodies and dwindling food supplies. Colonies rely on workers bringing nectar and pollen, but if flowering plants dry up, they produce less. Dr. Paul Williams, a bumblebee expert, explains that foraging is an energy calculation for bumblebees. They need to make a profit by collecting nectar, and they cannot afford to waste energy on dried-up flowers. The consequences of food scarcity are dire, as larvae develop more slowly, colonies grow weaker, and fewer new queens are produced for the following year. The UK's climate change-driven trend of more frequent and intense heatwaves poses a significant threat to bumblebees. Conservationists recommend creating flower-rich habitats to help bumblebees find food even in extreme weather. Dr. Sarah Beynon, an insect expert, has transformed her west Wales farm into a nature reserve by planting meadows, willows, hedgerows, tussocky grasses, and late-flowering crops. She emphasizes that people don't need vast land; a pot of native wildflowers on a doorstep or windowsill can act as a small refuelling stop for insects. Dr. Comont adds that adding a pond and shade can also help, as flowers near water produce wetter nectar, which can make colonies more resilient in hot weather. Planting dense shrubs provides bumblebees with shade and cooler patches of air to move through. This multifaceted approach to conservation is crucial in ensuring the survival of these vital pollinators in a rapidly changing climate.
