Glow Worm

The glow worm is a medium to large sized invertebrate that is famous for having a green and yellow coloured light on the end of its tail.

Glow worms are found inhabiting dense woodland and caves around the world with the exception of the Americas and glow worms are one of the few insects that are found inside the colder Arctic Circle. Glow worms are nocturnal animals which means that they are active during the dark night which is when their glowing rears can be seen.

Glow worm is the common name for various different groups of insect larva and adult larviform females which glow through bioluminescence. Glow worms may sometimes resemble actual worms, but all are insects as one species of glow worm is a type of fly but most glow worms species are actually beetles.

It is only the female glow worms that actually glow as they spend around 2 hours every night in the mating season with their bottoms in the air, trying to attract a mate. The male glow worms are attracted to the glowing object in the foliage but have also been known to be attracted to man-made lighting such as street lights.

Glow worms are most commonly seen in the UK between June and October and their green-lit tails tend to show up most clearly when the sun goes down at dusk. Legend says that early humans used to use glow worms to mark paths and provide light in huts. Glow worms were thought to have some kind of magical power and so people would also use the glow worm in medicines.

Glow worms are omnivorous animals but they tend to have a very meat-based diet. Glow worms predominantly prey on snails and slugs which make up the majority of the glow worm's diet. Glow worms also prey on other insects and small invertebrates.

Due to their small size and the fact that they glow in the darkness, glow worms have numerous natural predators within their environment including spiders, large insects, birds, reptiles and centipedes.

Typically, the female glow worm lays between 50 and 100 eggs in moist areas, over a period of a few days. The tiny glow worm eggs are yellow in colour and can take between 3 and 6 weeks to hatch depending on the climate (the warmer it is, the faster the glow worm eggs will hatch).

Glow worms are considered to be an animal species that are threatened with extinction as the glow worm population numbers are drastically decreasing. The main reason for the lower number of glow worms is thought to be the expansion of human civilisations. Glow worms are known to be particularly vulnerable to changes in their environment including habitat loss, noise and pollution.

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Sources:
1. David Burnie, Dorling Kindersley (2011) Animal, The Definitive Visual Guide To The World's Wildlife
2. Tom Jackson, Lorenz Books (2007) The World Encyclopedia Of Animals
3. David Burnie, Kingfisher (2011) The Kingfisher Animal Encyclopedia
4. Richard Mackay, University of California Press (2009) The Atlas Of Endangered Species
5. David Burnie, Dorling Kindersley (2008) Illustrated Encyclopedia Of Animals
6. Dorling Kindersley (2006) Dorling Kindersley Encyclopedia Of Animals