A fascinating new study highlights how the Franklin bumble bee, a rare species native to North America, was on a downward spiral toward extinction long before humans had their significant impact on the environment. This research suggests that the bee’s persistent genetic weaknesses have rendered it delicate and struggling to survive against both historical and modern environmental pressures.
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The insights from this critical study have been shared in the prestigious Proceedings of the National Academy of Sciences and involve researchers, including specialists from the University of Hawai‘i at Mānoa.
Researchers focused on this elusive Franklin bumble bee, which was once common in specific areas of Oregon and California, but was last spotted alive in 2006. By analyzing DNA from collected museum specimens over the past 40 years, they assembled a genetic timeline to decode the reasons behind the species’ extinction.
What they uncovered was startling: the bees possessed low genetic variation and clear signs of inbreeding that trace back thousands of years. The decline of their populations began during a glacial period and continued to deteriorate in more recent times, possibly due to natural disasters like drought and wildfires. Interestingly, the team found minimal genetic evidence suggesting that diseases or pesticide use led to the disappearance of these bees, challenging previous beliefs.
The limited number of Franklin bumble bees, coupled with their lack of genetic diversity, contributed to their vulnerability long before the onset of modern human effects, leaving them ill-prepared to handle natural crises like drought and wildfires.
Jonathan Berenguer Uhuad Koch, the study’s co-author and associate professor at UH Mānoa’s Pacific Cooperative Studies Unit, emphasized, “Bumble bees play a crucial role as pollinators not just for wildflowers but also for the food crops that are vital to human diets worldwide. In places like Hawai‘i, where local pollinators face challenges from habitat destruction, invasive species, and climate change, this study highlights how genetic elements significantly influence a species’ sturdiness against extinction.”
This study shines light on how museum collections can serve as powerful resources for contemporary conservation efforts. By dabbling in the DNA of preserved specimens, scientists can track fluctuations in population sizes and identify species that might face extinction in the future. The multi-institutional research team underscored the necessity of recognizing long-standing biological and environmental factors contributing to pollinator decline.
Koch expressed gratitude to Robbin W. Thorp, his late mentor, for inspiring his dedication to pollinator conservation. Their path crossed during his graduate studies, where they searched for the Franklin bumble bee together, which fueled his lifelong commitment to protect endangered bee species.
For further reading: Rena M. Schweizer et al, Museum genomics suggests long-term population decline in a putatively extinct bumble bee, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2509749122
Provided by the University of Hawaii at Manoa
This narrative initially appeared on Phys.org.
