Do street lights interfere with glow-worms?

Entomologist Richard Jones discusses the impact of human lighting on courting glow-worms.

Females glow-worm © Ian Redding/Getty

Yes. Male glow-worms find the
non-flying females by their green
glow. This cold light is produced 
by the chemical metabolism of a complex energy-storing molecule luciferin, by a special enzyme luciferase, and is the opposite of photosynthesis, releasing light photons into the night sky.

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Like moths, male glow-worms are attracted to artificial lights, which appear to confuse their navigation. The worry is that excessive lighting will distract them, preventing them from finding the females in the rough, grassy banks where they breed.

Recent experiments in a small Swiss town found that when road lighting was on, simple LED traps only received males in dark areas far from lamp posts, but when the lights were off, males occurred in all areas. The current thinking is that street lighting cuts ‘cheese holes’ in the beetles’ mating landscape.

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