A month ago I posted a picture of some fruit flies on a window and said I’d give details when the story is out.
Well, the story is out! That window was into a dragonfly flight arena; the flies were their food. The scientist I wrote about is Anthony Leonardo at the Howard Hughes Medical Institute’s Janelia Farm in Ashburn, Virginia. He’s trying to figure out how dragonflies catch their prey on the wing.
Keeping the dragonflies fed is a big feat. “A dragonfly might eat 50 to 100 flies in a day,” Leonardo says. “It adds up to a lot of flies.” If there are 20 dragonflies in the room, that means they need 2,000 fruit flies a day at the bare minimum–and more like 5,000 in practice, because “the dragonflies are certainly not going to scour the room to track down every fruit fly.”
Most of the people at Janelia study the neurobiology of fruit flies, so there’s never a shortage. “We think of that part of Janelia as, like, a food production facility,” Leonardo told me.