Many fascinating creatures are familiar by name but rarely seen by the majority of people, says Norfolk Wildlife Trust Reserves Officer, Robert Morgan. One such creature is the glow-worm.
The first fact to establish about the glow-worm is that it isn't a worm at all, but a beetle. The male is a classic beetle shape, it is dark brown with a slightly elongated body of about 25mm. The wingless female and its larvae look similar, but unlike the male their six legs are close together near the head. They also have a long segmented body trailing behind.
It is the female that emits a bright bioluminescent light from its tail-end; this strange glow in the dead of night is to attract the flying males.
Adult glow-worms cannot feed, but may live for up to 20 days, so hopefully within that time the female will attract a suitor. Sadly, soon after mating she turns off her light, lays her eggs, then dies. The 'cold' greenish light is produced by a complex molecule called lucifern and illuminates when oxygen is added. The larvae have a small light-emitting organ too and can sometimes twinkle briefly. Once the eggs hatch, the young glow-worms may spend up to three years in the larvae stage, feeding exclusively on slugs and snails.
There are two species of glow-worm in the UK: the lesser glow-worm is exceptionally rare, but its more common larger cousin can be found in most southern counties of England, with Norfolk being blessed with a number of sites. It tends to prefer heathlands or chalky downland, but ancient commons and meadows may hold a population too.
Venturing out on a warm, still evening in June or July, you may be rewarded with the magical sight of several glow-worms signalling in the dark of a mid-summer's night. Some will climb vegetation, others will find a bare patch of ground to display their strange but beautiful natural light.
This glowing creature of folklore and tale would have lit many a night-time traveller's path across the heath, but it is now, like many invertebrate species, in steep decline. The story is a familiar one of habitat loss, overuse of pesticide, artificial light disrupting courtship and development of marginal land, all of which has resulted in a general fall in the UK's insect numbers.
Norfolk Wildlife Trust's reserve at Buxton Heath is still a great place to see glow-worm, with many being found along the tracks that dissect the reserve. An evening visitor may also be rewarded with displaying nightjar too. Buxton Heath, just eight miles north of Norwich, is managed by NWT in partnership with Hevingham Fuel Allotment Charity and has undergone extensive habitat restoration work in recent years, being a site of a successful re-introduction of the silver-studded blue butterfly. It is also a fantastic reserve for the rare woodlark, as well as the world's largest aphid species and a staggering array of heathland mire plants.
You would be a very lucky person indeed to have glow-worm in your garden. If you do come across glow-worm elsewhere don't be tempted to take them home, as they need specialised habitats and are unlikely to prosper.
You can help a huge range of other insects by creating mini-habitats in your garden. Why not plant a plot of nectar rich wildflowers or stack up a pile of logs in a sunny corner? You could even build a 'bug hotel'.
Attracting new and interesting insects to your garden doesn't need a great deal of effort. Creating a bare patch of compacted ground may attract nesting mining bees or ground beetles. Just allowing a patch of lawn to grow tall can encourage grasshoppers and many other wonderful and vital wildlife.
Take a look at our Wildlife Information Service pages for more tips on how to take action for wildlife.
Header image: Glow-worm by Glyn Baker