The species of Arachnocampa are endemic to Australia and New Zealand, dwelling in caves and grottos, or sheltered places in forests.

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 roof of a cave covered with larva can look remarkably like a blue starry sky at night.

A hungry larva glows brighter than one that has just eaten..[citation needed] Prey include midges, mayflies, caddisflies, mosquitos, moths, and even small snails or millipedes.

Adult insects are poor fliers and so will often remain in the same area, building a colony of glowworms.

The larvae are sensitive to light and disturbance and will retreat into their nests and stop glowing if they or their snares are touched.