National Geographic : 1971 Jul
Glowing with a purpose, Waitomo's worms use their lights to lure the cave's flying insects into their snares, which are as ingenious as a spider's. Secreting a sticky substance, the larvae extrude it in threadlike fishing lines (left); one worm may dangle 70 such threads. Attracting prey with their lights, the glowworms trap the victims with the strands, then reel them in and devour them. A worm in its tube home (below left) poises above a catch-a winged adult of its own species. Threads radiat ing from the tube suspend the fisherman's home from the grotto ceiling. Snarled in another line, a hapless fly (below) dangles on a strand, at the mercy of its hungry captor. Though best known as resi dents of Waitomo's renowned caves, the glowworms abound throughout New Zealand in caverns, under bridges, and even amid ferns in damp ravines.