The Fascinating World of the British Glow worms

Finding out there is a British glow-worm inspired the kids and me to make fabulous lantern versions of our own. But we also wanted to find out more about these fascinating insects. What we found out was so interesting, we had to share.

Read on to discover all about the glow-worm, or head over to our glow-worm lantern instructions to find out how we made them.

A little bit about Lampyris noctiluca – the Common British Glow worm

“‘She isn’t really a worm at all. Glow-worms are never worms. They are simply lady fireflies without wings.'” 

James and the Giant Peach by Roald Dahl

If, like me, the only place in Britain you thought you might see a glow-worm is in the pages of James and the Giant Peach, you’d be even more wrong than Roald Dahl’s centipede. Britain is full of glow-worms, and as it turns out, they are neither worms or flies.

These amazing creatures are actually beetles, just like their equally mis-named cousins, the fireflies. And while the British glow-worm (or more properly, the European common glow-worm) is related to the American fireflies, they are a different species, not simply (sorry Mr Dahl) girls without wings.

Our British glow-worms can put on a subdued light show in their larva stage. But the flying males don’t glow at all – these guys are definitely not fireflies. It is only the larger, wingless adult female that really lights up. In the warm, summer months, these lady glow-worms climb long grass to attract mates by waving their brightly glowing bottoms. I say, missus!

Bright Lights, Little Worm

The bioluminescent light from a glow worm is as bright as an LED, and if you hold it close, even bright enough to read with. We were fascinated to discover that during World War I, soldiers in the trenches would use glow-worms to read maps, letters, and orders. The light was bright enough for them to see with, but not as bright as a lantern, which would have given away their position.

The glow-worm’s contribution to the war is commemorated on the Animals in War memorial in Hyde Park, London. And the BBC have some great resources on animals in wartime generally, including this rather hilarious War Horse trailer spoof, staring our favourite glowing insect: War Warm.

The British glow worm Lampyris noctiluca life cycle

British glow-worm adult females lay about 100 eggs at a time – each only a millimetre in size. When those eggs hatch, the glow-worm larva are only 5mm big. It takes another two or three years for them to reach full size, hunting down slugs and snails for food and moulting too-tight skins along the way.

Then, in the space of a few weeks, they pupate (just like butterflies), and emerge as adult glow worms. They do their mating dance, lay their eggs, then die, and the cycle begins all over again.

Are there fireflies in England?

Adult female glow-worms look very similar to the larva, but the males emerge looking completely different (a trait known as dimorphism). Adult male glow-worms are much more recognisable as beetles, and they can fly. But since they don’t glow, they definitely are not fireflies.

Male glow worms have two sets of wings, like other beetles – picture ladybirds, for example. The front set are actually casings, called elytra, which are to protect their delicate flight wings when not in use. They also have huge eyes – all the better to spot those glowing girls with!

But one thing the males and females have in common is that as adults they have no mouthpiece. So while the British glow-worm larva are accomplished predators, killing and eating slugs and snails several times their size, the adult glow-worm does not eat at all, and only lives a few short weeks after pupating.

British Glow-worm Lampyris noctiluca resources

Want to find out even more about the glow-worm? Here are some of our favourite sources of information.

Glowing beetle – Earth-born stars

The perfect place to start, this short film by Christopher Gent is a beautiful introduction to the UK glow-worm.

Lampyris noctiluca websites and articles

The Natural History Museum has a wonderful page about the glimmering world of glow-worms, which gives a great overview of the British glow-worm. This is the most child-friendly yet information-rich source we found.

Another good overview is this Country Life article: Secrets of the Glow-worm, although this is more suited for adults/older kids. It touches nicely on some of the literary mentions of the glow worm and contains some interesting bits of information we didn’t find elsewhere.

If you want to know how a glow-worm glows, check out this article on the world of bioluminescence from the Telegraph. Alternatively, try this page on what is bioluminescence, from the Natural History Museum.

This excellent article from The Guardian newspaper explores Why the lights are going out for fireflies all around the world, including right here in the UK.

Where to find glow worms uk

Want to see a glow-worm? The best time is in the summer, in June and July, when the lady glow-worms are lighting up. This UK Wildlife Trust page on where to see a glow worm has all the info you need.

The UK glow-worm survey website has lots of information and links. If you are out and about in the UK and see glow-worms, you can fill out a quick form to report your sighting. The website also has an active facebook page that’s worth checking out.

British Glow-worm books

It is surprisingly hard to find a children’s reference book about glow-worms. There are lots of children’s books about beetles, but the British glow-worm seems to be ignored in favour of the arguably more glamorous firefly, even in the gorgeous Brit-authored book, Bonkers About Beetles.

But keep a look out for mentions in general children’s reference books on insects and beetles and you may be lucky, All I’ve been able to find are brief mentions, so if you do find a good source, let me know!

Even for adults, there are only two books we found that are specifically and solely about British glow-worms (or the European common glow-worm). Both are self-published, but don’t let that put you off as they are both really well written and illustrated. So if you want a book about glow-worms, these are your options.

Lampyris noctiluca glow worms adult reference books

The Glow-worm by John Tyler
This was written by British naturalist John Tyler, who also has a fabulous website with a whole page of information about these curious creatures.

Full of fascinating information and some (occasionally pretty gruesome) pictures, this is a great reference book for those who want to delve deep into the life cycle of these curious creatures, but it is more suited to adult readers.

The Secret Life of Glow-Worms by John Horne
This is the other book – and though it’s little in size, it is packed full of information and immensely readable, with lots of great photos and illustrations. While it is also aimed at adults, because it is so clear and well illustrated it makes good reading for older children (my ten-year-old found it fascinating).

Both these books make great sources of information to pass on to kids, but it would be great to have a book or two that are written for them. If you happen to know of any (even if it’s just a page or two), let me know and I can add it to the list!

Finally, if you’re after academic research into the glow-worm, the Lampyrid  Journal Archive has a number of articles freely available online. Fascinating reading, but definitely for serious students only!

British glow worm podcasts and radio

If you’re a radio fan, check out this archived BBC Radio 4 Living World episode, where Chris Sperring and Robin Scagell (of the UK glow-worm survey) goes on a glow-worm safari in my home county of Buckinghamshire.

Or, for some more whimsical audio joy, try this half-hour podcast by Helen Swan on the Truth about glow-worms. It’s full of fact, fantasy, song and poetry about this little glowing nocturnal creature.