Bees have changed shape due to climate change stresses, study shows

Image credit: Foto 33477357 © Nikolay Petkov |

The Natural History Museum in London has found evidence that climate change is causing bees to physically change shape in response to increased environmental stresses.

In the new study, environmental changes have been shown to have a direct impact, such as the overuse of particular pesticides or extreme heat killing individuals, but more subtle effects have also been shown to be affecting the insects.

Four species of bumblebee from the UK that were held in museum collections over the past century were analysed and evidence was found that the insects have been getting increasingly stressed.

This could potentially have a knock-on impact on their health and their ability to adapt to the changing environment.

The research was able to use an approach that looked at the asymmetry of their wings to determine the amount of stress the individual insects were under when they were alive.

Dr Richard Gill at Imperial College London studies how human activities affect insect populations and was involved in the study.

“We’re seeing that bees are declining in populations across the world,” he explained. “What our work is starting to do is explain when, where and potentially how this stress is being placed on these bee species.

“By doing this we get a better predictive framework for understanding and forecasting where and when some of these populations are going to be most at risk when we get further environmental change.

“That’s very important if we’re going to start targeting conservation effort and start actually understanding how we can mitigate and safeguard these populations.”

The asymmetry of bumblebee wings – which is understood to be a signal of their underlying stress – has increased over the past 100 years. By comparing these changes to data on the environmental conditions that were occurring when the bees were alive, the researchers could determine that the bees were more stressed when the weather conditions were hotter and wetter.

The study also suggested that as climate conditions are exacerbated, with an increase in warmer, wetter years, bumblebees will be put under even more stress in the future. 

Further analysis, published in the Journal of Animal Ecology, showed that each species displayed a consistently higher proxy of stress in the latter half of the last century.

Co-author Aoife Cantwell-Jones, from the department of life sciences (Silwood Park) at Imperial College London, said: “By using a proxy of stress visible on the bee’s external anatomy and caused by stress during development just days or weeks before, we can look to more accurately track factors placing populations under pressure through historic space and time.”

Co-author Dr Andres Arce, now at the University of Suffolk, added: “Our goal is to better understand responses to specific environmental factors and learn from the past to predict the future.

“We hope to be able to forecast where and when bumblebees will be most at risk and target effective conservation action.”

Research from last year showed that simple changes to how UK solar parks are managed could boost ground-nesting bumble bee populations in the parks and surrounding areas, providing an additional benefit for nature on top of the renewable energy the parks produce.

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