Museum collections indicate bees increasingly stressed by changes in climate over the past 100 years: Scientists from Imperial College London and the Natural History Museum today published two concurrent papers analyzing UK bumblebee populations.
The first investigated the morphology (body shapes) of bee specimens dating back to 1900. Using digital images, the group first investigated the asymmetry in bumblebee wings as an indicator of stress. High asymmetry (very differently shaped right and left wings) indicates the bees experienced stress during development—an external factor that affected their normal growth.
Studying four UK bumblebee species, the group found evidence for stress getting higher as the century progressed from its lowest point around 1925. Further analysis showed that each bee species displayed a consistently higher proxy of stress in the latter half of the century. By taking the climate conditions during the year of collection—namely annual mean temperature and annual rainfall—the team found that in hotter and wetter years bees showed higher wing asymmetry. The study is published in the Journal of Animal Ecology.
In a second parallel study the team successfully sequenced the genomes of over a hundred bumblebee museum specimens dating back more than 130 years.
In a pioneering advance, ancient DNA methods typically used for studying wooly mammoths and ancient humans, were for the first time used on an insect population. Scientists from the Natural History Museum and the Earlham Institute quantified DNA preservation using just a single bee leg from each of the bees studied.
From these developments, published in Methods in Ecology & Evolution, the researchers can now look to determine how the reported stress may lead to genetic diversity loss. In conjunction with providing a new reference genome, the team will now use this data to study how bee genomes have changed over time, gaining an understanding of how whole populations have adapted—or not—to changing environments.