Glowworms Spit Out Urine Ingredient to Make Webs Sticky

By Laura Geggel, Senior Writer | December 15, 2016 02:35pm ET

Baby glowworms could be the interior designers of the cave world, if it weren't for their morbid machinations. These developing worms sit inside a tube of mucus on cave ceilings, sending out a curtain of sticky threads that look like sparkling beaded necklaces.

The purpose of the dazzling threads, rather than to enchant cave homes, is to trap unsuspecting insects. And now, researchers think they may have found the secret ingredient in the worms' traps: urea from their guts. 

The urea allows moisture in the humid cave to form droplets on the glowworms' secreted threads, the researchers found. These sticky, watery droplets trap insects drawn toward the blue-green light produced by the glowworms, the researchers said.

Baby glowworms could be the interior designers of the cave world, if it weren't for their morbid machinations. These developing worms sit inside a tube of mucus on cave ceilings, sending out a curtain of sticky threads that look like sparkling beaded necklaces.

The purpose of the dazzling threads, rather than to enchant cave homes, is to trap unsuspecting insects. And now, researchers think they may have found the secret ingredient in the worms' traps: urea from their guts. 

The urea allows moisture in the humid cave to form droplets on the glowworms' secreted threads, the researchers found. These sticky, watery droplets trap insects drawn toward the blue-green light produced by the glowworms, the researchers said. 

It's about time scientists solved this sticky mystery, said study co-lead researcher Janek von Byern, a postdoctoral fellow at the Institute of Zoology at the University of Vienna and the Ludwig Boltzmann Institute for Experimental and Clinical Traumatology in Austria.

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Spider Webs More Effective at Ensnaring Charged Insects

July 4, 2013 — Flapping insects build up an electrical charge that may make them more easily snared by spider webs, according to a new study by University of California, Berkeley, biologists.

The positive charge on an insect such as a bee or fly attracts the web, which is normally negatively or neutrally charged, increasing the chances that an insect flying by will contact and stick to the web, said UC Berkeley post-doctoral fellow Victor Manuel Ortega-Jimenez.

He also suspects that light flexible spider silk, the kind used for make the spirals on top of the stiffer silk that forms the spokes of a web, may have developed because it more easily deforms in the wind and electrostatic charges to aid prey capture.

"Electrostatic charges are everywhere, and we propose that this may have driven the evolution of specialized webs," he said.

Ortega-Jimenez, who normally studies hummingbird flight, became interested in spider webs while playing with his four-year-old daughter.

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Southend cemetery covered in ghostly moth webs

Trees in an Essex cemetery have been covered by a giant silvery blanket, described as "spooky" and "ghost-like" by locals. But the strange phenomenon is in fact the work of a legion of caterpillars.

Bird cherry ermine moth caterpillars (Yponomeuta evonymella) appeared a few weeks ago and now cover everything from shrubs and hedges to the tombstones in Sutton Road Cemetery in Southend-on-Sea.

Curator of natural history in the borough, Roger Payne told Channel 4 News: "The caterpillars work in boom and bust cycles. Their main predators are parasites and in particular the parasitic wasp which buries its eggs inside them.

"There appears to have been fewer of those this year hence the increase in the number of caterpillars."

There are eight different varieties of ermine moth.

The bird cherry species is just one and is named after the tree it both feeds on and lays its eggs in. The caterpillars don’t harm the host they rely on to survive, but they are known to strip the trees entirely of their leaves when feeding.

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