We donned our striped thermals, rubber boots, and helmets and tramped down a muddy hillside to the entrance to Mangarongapu Cave. If we wanted to see glowworms in their natural environment, we were going to have to work for it. Most bioluminescent organisms live in the sea, particularly in the deep. On land, bioluminescent species include glowworms, a catch-all term that refers to luminescent insects like fireflies (winged beetles) and the fungus gnat of New Zealand, among others.