New super-glue inspired by slug slime

Surgeons close internal incisions with stitches and staples but they, and their patients, would benefit from a glue that stays stuck even to wet tissue and organs. Researchers from McGill University in Montreal are making progress with a powerful new glue inspired by the the sticky slime secreted by scared slugs. Science News surveys the state-of-the-art in adhesives that take inspiration from marine worms, mussels, and geckos:

Using the (slug-inspired) glue to plug a hole in the pig heart worked so well that the heart still held in liquid after being inflated and deflated tens of thousands of times. (McGill University's Jianyu) Li, who did the research while at Harvard University, and colleagues also tested the glue in live rats with liver lacerations. It stopped the rats’ bleeding, and the animals didn’t appear to suffer any bad reaction from the adhesive...

One layer of the material is a polymer, a type of material made from long molecules built from many repeated subunits, like a string of beads. Positively charged appendages dangling off the polymers are drawn to wet tissue surfaces by the same forces underlying static electricity. This first layer weaves into another layer, a water-based gel. The gel layer acts like a shock absorber in a car, Li says. It soaks up energy that might otherwise dislodge or snap the adhesive.

Despite being 90 percent water, the material is both sticky and tough, Li says. The fact that it’s mostly water makes it more likely to be nontoxic to humans. Read the rest

Slugs eat tiny hatchling birds

Mercifully there is yet to be footage of slugs devouring baby birds, but the fact that it happens has been confirmed after years of suspicion.

“The actual moment of slugs predating on nestlings isn’t easy to observe,” says Katarzyna Turzańska at the University of Wroclaw in Poland. “You are more likely to come across the traces of the ‘tragedy’: dead or alive nestlings with heavy injuries, covered in slime – and often slugs’ droppings found nearby.”

She and Justyna Chachulska, a colleague at the University of Zielona Góra in Poland, were studying common whitethroat birds near Wroclaw, in Poland, when they spotted a slug of the Arion genus in a nest with newly hatched chicks. The next day, the slug was gone, and the chicks were dead with severe injuries on their bodies that hinted at the slug as the culprit.

They were gobsmacked. “We couldn’t believe that the slug had killed the nestlings,” says Turzańska. “We talked to many experienced ornithologists, but none of them had observed slug predatory behaviour towards birds before.”

For your enjoyment, the Trailer to Slugs (1988).

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Mollusk biologist describes how slugs make babies

John Kelly of the Washington Post spotted a pair of leopard slugs mating on his driveway. He called Megan Paustian, a research biologist who consults for Smithsonian’s National Museum of Natural History, to explain how slug sex works.

After Paustian told Kelly that she was "kind of jealous" that he got to watch a live leopard slug sex act when she has only been able to watch leopard slug porn, she went on to explain how they do it: “They make a mucus thread and then dangle down on it. As they hang there, the hermaphroditic slugs extrude their translucent penises — out of their heads. They swap sperm.”

Ever wondered how slugs make more slugs?

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Hot pink slugs

This fantastically pink slug, Triboniophorus aff. graeffei, is only found on Mount Kaputar, a mountaintop in New South Wales, Australia. According to scientists, the slugs and several other strange species are from the days when this region was a damp rainforest. When Mount Kaputar erupted 17 million years ago, it preserved a very unusual ecosystem. "A series of volcanos and millions of years of erosion have carved a dramatic landscape at Mount Kaputar National Park, creating a fascinating world with some very colourful locals," writes the NSW National Parks and Wildlife Service on its Facebook page. More info in the Sydney Morning Herald. (Thanks, Gabe Adiv!) Read the rest