Threatened bumblebee populations in England and Wales are experiencing significant genetic declines, according to a new study based on museum specimens. The moss carder bumblebee, once common in the UK's flower-rich meadows, marshes, and heathlands, has become more confined to coastal and island areas due to habitat loss. As these populations shrink and become isolated, they lose genetic diversity, increasing the risk of inbreeding and reducing their ability to adapt to environmental changes. Researchers analyzed the DNA of over 100 moss carder bumblebee specimens stored in museums across the UK. They discovered that genetic diversity has dropped by about 25% over the past century. In England and Wales, the portion of the genome affected by inbreeding has nearly tripled, suggesting that populations are smaller and more isolated than before. The study highlights an "unexpectedly high" rate of genetic loss, driven by factors like wetland drainage, the disappearance of meadows, and the use of pesticides. In contrast, populations in the Scottish Highlands show less genetic decline, possibly because their habitats are better connected, allowing for more genetic exchange. Scientists suggest that introducing Scottish bumblebees into English and Welsh populations could help restore genetic diversity through targeted conservation efforts. However, such actions would need to be paired with addressing the root causes of the bee's decline, such as habitat destruction and pesticide use. Dr. Victoria Mullin, co-author of the study and assistant professor at Trinity College Dublin, explains that the research confirms the moss carder bumblebee's shrinking numbers are reducing its genetic diversity. This decline weakens the species' ability to cope with challenges like climate change, pollution, and habitat degradation. The study was made possible by projects like Darwin Tree of Life, which aims to sequence the genomes of over 70,000 UK species. This initiative helped identify 29 museum specimens previously thought to be moss carder bumblebees but were actually close relatives, improving the accuracy of the research. Professor Ian Barnes, a co-author and merit researcher at the Natural History Museum, emphasizes the role of museum collections in understanding biodiversity changes. The museum holds around 30 million insect specimens, with many more in other UK institutions. These collections provide the necessary scale to address important questions about species decline and conservation strategies. The study underscores the value of preserving such collections for future scientific research and environmental planning.