Air Date: Week of December 5, 2003

Living on Earth's Cynthia Graber reports that snails are farming fungus in southern marshes.

Transcript

CURWOOD: Just ahead: black bears in the back yard. First, this note on emerging science from Cynthia Graber.

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GRABER: Scientists have known that certain species of ants, termites, and beetles actually farm the fungus they eat. Now you can add snails to the list. Scientists researched snail populations in 16 marshes in eight states along the southeastern U.S. coast. They knew that snails snack on fungus that grows on dead plant material. And recent research has shown that these snails occasionally snack on live marsh grasses as well.

But the new research showed something surprising. The snails aren’t actually eating the grass. Instead, they slash away at the plants as they move. Then, they deposit fecal matter on the torn up areas, four times as much as they deposit on any other area of the plant. The fecal matter contains fungal spore, because the snails only digest about half of what they eat. And the fungus grows along the edges of the dying plant material. Finally, the snails return and feed on the fungus that they’ve planted. In addition to providing food, the fungus also limits the growth of the marsh grass. So by farming fungus, snails also control the marshes. That’s this week’s note on emerging science, I’m Cynthia Graber.

CURWOOD: And you're listening to Living on Earth.

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