Most of us who have encountered slugs know that if you handle one, the slime it produces on the lower surface of its body persists on your hands even when you wash them with soap and water. (If you let the slime dry and rub your hands together, it will come off in small beads.) Slug slime contains water, mucus and salts. It keeps a slug’s skin moist, preventing it from drying out, and aids in locomotion.
Slug slime changes as the slug moves. Initially it has the consistency of a liquid gel. It is solid at rest and turns to liquid under pressure. A slug sticks part of its body to the ground with its slime, uses its muscles to move its body forward, and then pulls its body away from where it was stuck. More slime is released and the process is repeated. It’s interesting to note that slugs are strong enough to move without the aid of slime, but nonetheless are always producing it.
Slug slime has its good and bad points. Scientists are studying slug slime properties in their search for a better surgical adhesive. Most substances are either flexible or sticky, not both, like slime. On the other hand, there are some aspects of slug slime that are not all that appealing. In addition to being next to impossible to remove from your hands, slug slime can carry rat lungworm (Angiostrongylus cantonensis), a parasitic roundworm that mainly lives in rodents such as rats and can infect slugs (and snails) that come into contact with infected rodent feces. This disease can cause a form of meningitis which is prevalent in Southeast Asia and tropical Pacific islands.
(Photo: Two slugs & bubble of slime. Nature of activity not determined! Thanks to Alice Trageser and Mary Landon for photo opportunity.)
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