By Susan Milius
The first big study of daily rhythms in fruit flies outdoors doesn’t match some of the basic results from decades of lab tests.
Fruit flies flittering in lab containers have revealed much about how light can set the master molecular clock that ticks out a daily beat in living organisms. Yet watching daily rhythms in fruit flies caged outdoors reveals regular surges in activity not seen in the lab, says geneticist Rodolfo Costa of the University of Padova in Italy. And certain patterns of activity seen in the lab don’t show up in the real world, he and his colleagues report online April 4 in Nature.
A major difference, he says, is that the typical increase in fruit fly motion as day dawns doesn’t seem to need a built-in clock in the real world. Flies with genetic mutations that disable their biological clocks don’t join in the usual laboratory bustle of activity before lights-on. Yet outdoors they perk up and get moving just like clock-normal flies. “This was something really unexpected,” Costa says.