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 larvae can only live in a place out of the wind, to stop their lines being tangled, hence caves, overhangs or deep rainforest. In some species, the droplets of mucus on the silk threads are poisonous enhancing the trap's ability to subdue prey quickly.
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. A hungry larva glows brighter than one which has just eaten.