The Waitomo Caves are not only spectacular geologically, they also boast some striking inhabitants: glowworms (Arachnocampa luminosa). The larva of the fungus gnat is a luminous insect that hangs on silk from the roof of the caves and glows bright blue/green. The glow, which is the result of phosphorescent chemicals from the bug’s intestine, is used to attract mayflies that enter the cave to mate.
The worms spin a network of silk threads across the rocky ceiling so they can move around with ease. Then, at different intervals, they create individual threads that dangle down and are covered in sticky mucus. Mayflies, attracted by the glow from the worms, fly up to the ceiling where they become entangled in the sticky traps. When a victim has been ensnared the worm switches off its light (to conserve energy) and hurries along the silk pathways to feast on the prey. The more danglers the glowworms make the more chance they have of capturing lunch.
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