These slimy threads are ‘fishing’ lines in New Zealand’s Waitomo Caves. The lures are the bioluminescent glow of Arachnocampa luminosa, or glow worms. Their carnivorous larvae create a starry night sky a half a mile deep in the caves, attracting unsuspecting moths, midges, mosquitos, mayflies, and more. KQED’s Deep Look series takes us there. Plus, a bit of history from Wikipedia:
The species was first described in 1871 when collected from a gold mine in New Zealand’s Thames region. At first it was thought to be related to the European glowworm beetle, but in 1886 a Christchurch teacher showed it was a larva of a gnat, not a beetle. The species was called Bolitiphila luminosa in 1891, before being renamed Arachnocampa luminosa in 1924.