Female glow worms do not actually fly. Glow worms are a type of beetle, and the females lack wings entirely. The larvae and adult males may have small wings, but the wingless females stay grounded their whole lives.
What are glow worms?
Glow worms are a family of beetles that can emit light from their abdomens. There are around 30 different glow worm species, most of which live in tropical environments. The most well-known glow worm species is the common European glow worm, Lampyris noctiluca.
The glow worm’s light comes from a chemical reaction inside special light organs in the abdomen. The light is used to attract flying males for mating. Only the larvae and adult males have wings – the adult females are wingless.
Do the females ever fly?
No, female glow worms do not fly at any stage of their life cycle. The larvae hatch from eggs laid on the ground and crawl around hunting for snails and slugs. When they are ready to become adults, they attach themselves to plants, rocks or fences and pupate.
The adult female emerges wingless, and stays in the area near where she pupated. She continues glowing after dark to attract flying males. After mating, she lays eggs and dies within a few days.
The adult male glow worms have wings and are the only ones capable of flight. They fly around at night to find the glowing females. After mating, the males also die within a few days.
Why don’t the females have wings?
There are a few theories as to why female glow worms lost their wings over evolutionary time:
- Flying requires a lot of energy. Staying grounded allows more energy to be put into reproduction.
- Not having wings reduces predation. Birds find it harder to spot wingless insects on the ground.
- Wingless females can put more resources into producing eggs and glowing lights.
- Short adult life spans mean they don’t need wings to search for food or mates.
Having wingless females is common in many insect species where the adult stage is focused on reproduction. Other examples include mayflies, dragonflies and stoneflies.
Can glow worms move on the ground?
While flightless, female glow worms are still capable of crawling around. Their short legs allow them to walk and climb over vegetation, rocks and fences. However they move quite slowly compared to winged insects.
The larvae can move around more actively hunting for prey. They have six legs for crawling about in search of snails and slugs to feed on.
When glow worms need to disperse to new areas they rely on passive methods like wind, animals or water currents to transport them. Their limited mobility makes glow worms vulnerable to habitat loss and fragmentation.
Conclusion
Female glow worms cannot fly at any point in their lifecycle. The wingless adult females stay grounded after emerging from pupation, using bioluminescent lights to attract flying males for mating. While they can crawl short distances, their lack of wings limits the female glow worms’ independent mobility and dispersion. This flightlessness sets them apart from the larvae and males, which have small wings for getting around. Overall, not having wings allows female glow worms to conserve energy for reproduction in their short adult stage.