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Citizen Scientists Scramble to Revive Vanishing Glow-worm Populations
7 Nov
Summary
- Glow-worm numbers in the UK have plummeted from 248 in 2017 to barely 50 in 2024
- Threats include habitat loss, light pollution, and climate change impacts on prey
- Volunteers and researchers are attempting glow-worm reintroduction and habitat restoration
In 2025, glow-worm enthusiasts across Europe are sounding the alarm as populations of the bioluminescent beetles continue to plummet. Once a common sight on summer nights, the glow-worms are now struggling to survive.
Volunteers in the UK have been monitoring glow-worm populations for nearly two decades, and their findings are dire. In 2017, they counted 248 glow-worms in the village of Westbury-sub-Mendip, Somerset. But by 2024, that number had dwindled to barely 50. Similar declines have been observed in France, Germany, and Spain.
Experts attribute the glow-worm's decline to a range of threats, including habitat loss, fragmentation, and light pollution. As female glow-worms cannot fly, they are particularly vulnerable to changes in their immediate environment. Even something as minor as a new ditch can devastate a local population.
Climate change also poses a grave threat, as hotter summers disrupt the glow-worms' food sources of slugs and snails. Researchers warn that more than 40% of insect species are in decline globally, and the picture may be even more dire than currently known.
In response, some people are taking matters into their own hands. In Italy, a physics professor has reduced light pollution in his garden, allowing the glow-worms to thrive. In the UK, an ecologist has begun breeding glow-worms in captivity with the goal of reintroducing them to areas where they have not been seen for decades.
These efforts, however, are not without their challenges. Glow-worm enthusiasts are divided on the merits of reintroduction, and experts caution that the success of such programs is far from guaranteed. The key, they say, is to first understand why the glow-worms disappeared in the first place and address those underlying issues.
As the fight to save the glow-worms continues, one thing is clear: these bioluminescent beetles have a unique power to captivate people and serve as a "gateway drug" to connecting with nature. For those who have witnessed the magic of a summer night filled with their tiny flickers, the loss of the glow-worms would be a tragedy indeed.
