The Glowing Spider-Worms of New Zealand

For over one hundred years, millions of tourists have flocked to the ancient limestone Waitomo Caves on New Zealand's North Island, where stunning species of fungus gnat called Arachnocampa luminosa live. 

The genus is unique to New Zealand and Australia, and they are found in caves, grottoes, and other sheltered places. Arachnocampa means 'spider-worm,' as the gnat is known for the way their larvae hang strong vertical silk threads from the ceilings of their underground habitats. The threads are from one to fifty centimetres long and are studded with evenly spaced drops of sticky mucus, acting like fishing lines to lure in prey. Since the larvae are luminescent, the thousands of tiny threads light up cave ceilings like a starry sky. Other insects are attracted to the light and fly up—but then become ensnared in the sticky mucus, which contains proteins that researchers think may act as an anaesthetic. The larvae live this way for many months, trapping and devouring their prey, before becoming a shot-lived adult gnat.