© MPI f. Chemical Ecology/ P. Kumar
The caterpillar of the tobacco hornworm feeds on the leaves of wild tobacco plants. It uses the plants' defense mechanism for its own purposes to deter spiders.
Alice in Wonderland’s puffing caterpillar may have been more health-conscious than we thought!
This is Sandra Tsing Loh with the Loh Down on Science
Finding the silver lining in smoker's breath.
At least for tobacco hornworm caterpillars. As their name suggests, they love to munch on tobacco. Yum. Tobacco contains nicotine, the chemical poison that causes a smoker's buzz. Yuck.
But in the caterpillar, it's not poison. It's protection! So say molecular ecologists from Germany. They found that caterpillars munching on tobacco plants can fend off predators simply by breathing on them!
It's like this: A hungry wolf spider moves in. The caterpillar exhales. And ick! The spider flees! I mean, who can blame it?
The scientists then found the gene responsible for shuttling nicotine from gut to spiracles. Spiracles are insect air holes, which is how the nicotine gets exhaled. When the scientists shut that gene off—so no nicotine breath—guess what? The bug got eaten! And when the caterpillar ate plants without nicotine? There was a well-fed spider, and a missing caterpillar.
And, unlike with the Cheshire Cat, there wasn’t even a smile left behind.
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