The Glow-worm is a medium-sized, narrow beetle. The males look like typical beetles, but the females have no wings and look similar to the larvae. Glow-worms are most often found as larvae, which live under rocks on chalky grassland and feed on slugs and snails. Females are famous for emitting a greeny-orange light from their bottoms at night. They climb up plant stems and glow in order to attract males, who have large, photosensitive eyes - perfect for scanning vegetation at night. The larvae can also emit light, and so can the eggs. Adults are only around for a short period in June and July.
How to identify
The nightly glow of a female Glow-worm is unmistakeable. The male is a light brown, typical beetle. The larva is greyish-brown with yellowy-orange triangular markings at the side of each segment. The female is similar in appearance to the larva.
Where to find it
Since the 1950s, there has been anecdotal evidence suggesting a decline in glow-worm populations, not just in Britain, but in the whole of Europe. Gardens, hedgerows, railway embankments, woodland rides, heathlands and cliffs are all possible habitats for glow-worms, with them particularly favouring limestone or chalky areas. Currently, the species can still be found in parts of England (especially the south), lowland Scotland and Wales.
When to find it
How can people help
Light pollution from street lights, houses and outdoor lights is a serious problem for Glow-worms, disrupting mating behaviour: the males are attracted to the lights instead of the females. Areas with less light pollution have larger Glow-worm populations, but glow-worms are still declining, partly due to the loss of chalk grassland habitat - we've lost about 80% of our chalk grassland over the last 60 years. The Wildlife Trusts manage many grassland and downland nature reserves for the benefit of the rare wildlife they hold. You can help too: volunteer for your local Wildlife Trust and you could be involved in everything from scrub-cutting to stockwatching. You can also help glow-worm conservation at home by creating a desirable habitat for glow-worms in your garden by building a log pile. When temperatures get too hot, this will give the larvae somewhere to hide and gain protection from drying out. The log pile is also great for attracting snails – the perfect meal for glow-worm larvae.