Bombus dahlbomii has been evaluated as Endangered on the IUCN Red List of Threatened SpeciesTM. It is is the world’s largest bumblebee (queens can grow up to 4cm in length!) and occupies the southernwest most portion of continental South America. Locals and researchers affectionately call it the “flying mouse” and “flying teddy bear”.
This species used to be the only bumblebee in Patagonia and was widely distributed throughout the region. Unfortunately, populations began to rapidly decline following the introduction of Large Garden Bumblebees (B. ruderatus) and Buff-tailed Bumblebees (B. terrestris) from Europe. Buff-tailed Bumblebees were introduced to Chile in 1997 for agricultural pollination purposes and reached Patagonia in 2006 which triggered the collapse of the native B. dahlbomii population. The commercially reared European species were found to be infested with the parasite Apicystis bombi, which likely played a large role in the decline of B. dahlbomii.
Improved knowledge of the mechanism (e.g., pathogen transmission, competition) leading to the replacement of B. dahlbomii with introduced species is required to prevent this species’ further decline. Import of non-native bumblebee species needs to be prevented, and any populations which have become established should be controlled and eradicated.