The twinkling fairylike lights of glowworms enchant both adults and children. These little larvae shine as bright as they can to attract other insects for food. If you live in an area where glowworms are found, see if you and your kids can discover some during the summer months. Meanwhile, share fun facts about these "supernatural" insects.
A Glowworm Is Not a Worm
While the larvae or young of these insects might look like small, slithering worms, glowworms are not actually worms. "Glowworm" is a common name for various different types of insect larvae and adult insects that have the ability to to give off a green or yellow glow. These insects are actually types of beetles and flies. Adult glowworms are invertebrates, meaning the skeleton is on the outside of its body. Also referred to as European glow-worms and fireflies; the most common glowworms are bioluminescent beetles.
How Glow Worms Glow
All types of glowworms emit their light by a similar method called bioluminescence. This occurs due to natural chemicals that are found inside their bodies. As the chemicals react they produce a fluorescent light that shows through the outer skin or skeleton of this little critter. Some types of glowworms have larger organs for producing bioluminescent chemicals for a brighter and longer-lasting glow. A glowworms glows for two reasons: to attract a mate or prey, and to scare away predators.
The Females Glow the Brightest
Like mosquitoes, in which only the females suck blood, it is primarily the female glowworms that have the ability to glow. During the mating season, the female spends about two hours every night giving off a bright bioluminescent light from the abdomen and rear to attract a mate. The male glowworms are attracted to the light, but can sometimes be misdirected by street lights and other lighting. The females survive through only a short period of a few weeks to mate and lay eggs, before they die. The adult males and larval young can only produce a faint glow to help attract the prey they need for food. The glowworms' light is also a warning for predators such as birds, spiders and centipedes to stay away. The bioluminescent chemicals inside them are toxic to other insects and animals.
Glowworms are found in dense, undisturbed woodland areas and caves around the world, though they are not as common in North America and South America. They are among the few insects that are also found in the cooler climates of the Arctic Circle. In most areas, you can find glowworms between the months of June and October, particularly at dusk when the sun goes down.
Adults Rarely Eat
Young glowworms called larvae are predatory and hunt for snails, slugs and other insects to eat. They have a predominately meat-based diet but also eat leaves and other plants sometimes; this makes glowworms omnivores. However, once they have morphed to the adult stage, glowworms rarely feed. The adults are busy protecting their young and laying new eggs.
Glowworms Are Endangered
According to legends, glowworms were so common that their brightly lit tails were used to light paths and provide light inside huts. However, today glowworms are considered an endangered species that are threatened with extinction, as their population rapidly decreases. This may be because many of their natural wooded habitats are being cut down to make way for towns and roads. Glowworms are also particularly sensitive to changes in their environment such as pollution, noise and lights. As they only have an average life span of five months, they must mate and lay eggs quickly. Protecting conservation areas where they are found will help to save glowworms and other endangered animals and insects.