What a beautiful trap! These glow worms make a sparkling net on the cave ceiling, perfect for catching flying insects, in this Sir David Attenborough-narrated clip from the BBC’s Planet Earth: Caves and/or Life in the Undergrowth. From Wikipedia:
Arachnocampa is a genus of four fungus gnat species which are, in their larval stage, glow worms. They are found mostly in New Zealand and Australia in caves and grottos, or sheltered places in forests.
The larva spins a nest out of silk on the ceiling of the cave and then hangs down as many as 70 threads of silk (called snares) from around the nest, each up to 30 or 40 cm long and holding droplets of mucus…
The larva glows to attract prey into its threads, perhaps luring them into believing they are outdoors, for the roof of a cave covered with larva can look remarkably like a starry sky at night.
In the archives: more bioluminescence.