Fly Behind Bars

Stuck behind bars for a crime he didn t commit? Nah, this fruit fly is part of an experiment to uncover how insects navigate thousands of miles duringmigration, or even find their way from flower to flower in the front yard. The bars of light demarcate a light emitting diode (LED) flight arena, but what really holds the fly in is a magnetic field (he s glued to a metal pin, allowing him to move naturally within the field but keeping him in place). The outcome of this bizarre set up is the discovery that fruit flies look to the sky to keep their bearings. In naturally polarized light, the flies had no trouble staying on course. But when researchers altered the light polarization patterns, the flies got discombobulated. That means that as long as a bit of sunlight makes its way to the fly s eye, it can use the patterns in light to get where it s going sort of an all weather version of sailors navigating by the stars. The researchers reported their results Jan. 10 in the journal Current Biology.