C. elegans (Photo: Dan Dickinson)
Many animal species, from butterflies to turtles, can sense the Earth’s magnetic field—it’s one way they keep on course as they move around the world. But scientists have been puzzled as to how, exactly, animals sense those forces. Now, by examining the brains of worms, scientists at the University of Texas say they have made ”the first discovery of an actual sensory neuron that detects the Earth’s magnetic field.”
That sensor, according to UT, “looks like a nano-scale TV antenna.” It’s teeny tiny, at the end of a neuron. But it’s that sensor, they think, that tells C. elegans worms what’s up and what’s down.
To show that the worms used the magnetic field to navigate, the scientists put the worms in tubes of gel. If native Texas worms were full, they moved up, and if they were hungry, they moved down.
Then, the team looked at worms from Australia and England. These worms also move towards what they thought was down when they were hungry. Only, for them, down meant “the magnetic vector that would optimize vertical translation in their native soil.” In practice, the Australian worms actually moved up—or what looked, in Texas, to be up. The worms were traveling along the magnetic vector that, for the rest of their short worm life, had always directed them down deeper into the soil.
The team published these results in the journal eLIFE, along with more details on how they identified the actual sensor in the brain that was keeping the Texas worms well oriented and telling the poor Australian worms that what was up was down and what was down was up.
(Image: Bob Goldstein)
Bonus finds: Some of the universe’s earliest stars, the Patagonian version of the Welsh national anthem, 60,000 bees, a Casio watch that’s still working 20 years after it was lost, a pink rattlesnake, and a long lost reel of Laurel & Hardy hitting each other with pies
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