Glowing insects have returned to the Nosterfield nature reserve in North Yorkshire for the first time in more than 100 years. Over several weeks this summer, volunteers counted up to 12 glowing female glowworms at the reserve. The sightings show that a small project to bring the rare invertebrates back to the area is starting to succeed.
Glowworms disappeared from the reserve due to past quarrying, while across Britain their numbers have dropped because of modern farming, development, and outdoor lighting. To help them return, ecologist Pete Cooper spent six years learning how to breed the beetles. He collected a small number of glowworms, bred them, and raised hundreds of young larvae in a garden shed before releasing them at Nosterfield in 2024.
Glowworms take two years to grow into adults. Female glowworms cannot fly, so they produce a bright light to attract flying males in the dark. Because the larvae released in 2024 have now reached adulthood, they can mate and lay eggs in the reserve's restored grassland. Cooper and local volunteers have raised another 1,900 larvae to release later this year, supported by funds raised at local community events.
Conservationists say the recent sightings are an encouraging sign of progress. However, experts will continue monitoring the site until 2030, when the offspring of this summer's wild adults mature, to confirm if the reserve has a self-sustaining glowworm population.