Researchers examined the composition of the stick threads dropped by cave glowworms to catch prey. Photo by Madeleine Deaton/ Flickr

Images captured by a scanning electron microscope revealed mineralized crystals inside the beads lining the glowworms' sticky threads. Photo by Janek von Byern et al./PLOS ONE

CHRISTCHURCH, New Zealand, Dec. 14 (UPI) -- Walk through a cave in New Zealand and there's a chance you might find yourself face to face with sticky strands of urea beads. As new research revealed, a unique species of cave glowworms on the island nation uses adhesive "fishing lines" to catch dinner.

Insects are drawn to the light of the New Zealand glowworms, Arachnocampa luminosa, and become trapped in the sticky threads. Unlike spider web threads, the glowworm's beaded threads are absorbent and moist. In addition to catching prey, the absorbent threads may help the glowworms collect water and avoid dehydration.


Researchers used scanning electron microscopy and X-ray spectroscopy to analyze the molecular composition of the fishing lines. The imaging revealed mineralized crystals within the beady droplets, including urea crystals -- a main ingredient in urine.

Scientists suspect the thread is created in the midgut, where components of the worm's primary urine is incorporated before it is expelled through the worm's mouth.

Researchers described their analysis of the unique adhesive threads in the journal PLOS ONE.

"Characterization of the adhesive threads of the world-renowned glowworm from New Zealand display a complete different prey capture system to those found in spiders or other glue-producing animals," lead study authro Janek von Byern, a researcher at the Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, said in a news release. "These bioadhesives display a unique composition contain mainly water, hygroscopic salts, and to a very low extent also biomolecules as proteins and lipids."