Just as birds guide their migratory journeys by sensing Earth’s magnetic field, so do cockroaches use geomagnetic detection as they scurry across your kitchen floor.
To reveal the mechanisms of cockroach navigation, Czech researchers first placed roaches inside an artificial magnetic field. As they rotated the field, the cockroaches followed.
In itself, this wasn’t surprising: Scientists know that cockroaches, like many insects, can detect magnetic fields. But they weren’t sure if cockroaches have “mapping” cells in which minute variations in Earth’s geomagnetic field cause pairs of quantum-entangled electrons to spin in different ways, or “compass” cells in which embedded iron particles respond to geomagnetic tugs.
When the researchers flooded the roaches with radio waves known to disrupt electron-paired compass cells, the cockroaches no longer followed the turning field. They apparently use a map to steer. And as cockroaches have been around for 350 million years, the mapping system could be widespread in the insect world.
“Insects may be equipped with the same magnetoreception as the birds,” wrote the researchers in a paper published Friday in the Journal of Experimental Biology.
As for why cockroaches need such sophisticated magnetoreception, that remains a mystery. But at least one explanation can, unfortunately, be ruled out: They don’t use their map to go south for the winter.