Glowworms' Secret Finally Revealed: What Is In Their Snares?

The animal world is full of amazing things -- spiders that have webs stronger than steel, octopi that are masters of disguises and tigers that can climb trees as well as swim great distances.

Then, there are glowworms: bioluminescent creatures that lure insects into their hammock of sticky threads in caves and other dark, dingy places near water. These Australia and New Zealand natives are known to catch their dinners via their blue "butts." But it was not until recently that biologists figured out what they used to make their sticky "fishing lines."

The main ingredient: urine.

PBS.org reported that Austrian zoologist Janek Von Byern and his team made the discovery when they collected fishing lines from glowworms (Arachnocampa luminosa) living in two caves on the northern island in New Zealand. The study, which was published in the journal PLOS One, noted that all nine species of these glowworms light up thanks to the bioluminescent organs that they have near their rear end. Unlike spider silk, however, these glowworms spew sticky threads from their mouths -- not from their butts.

Byern and his team analyzed the components of the threads with the help of the electron microscopes and X-ray spectroscopy. They found that these threads are coated with a type of glue and mucus-like droplets that are considered as main components of insect waste and urine. "We think that the glue is part of the excretion of the waste from the insect and they just spit it out... and attach it to the silk thread," Byern said.

This is the first time that scientists found urine in a bioadhesive from animals, Popular Science noted. Though the glue from glowworms is not as strong as those from spiders, it could still inspire adhesive for several things, including furniture, paper or cardboard. "It was no matter if it was just dry clothes or if it was something wet, it sticks to anything so long as the humidity is above 80 percent."

Glowworm glues could have their own uses, especially considering that theirs is a more versatile version than those of other animals that also produce these sticky substances.