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...