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Fruit flies can travel miles a day without getting lost

Fruit flies just may have some superpowers. The tiny insects appear to come equipped with their own internal, sun-powered compasses – and they can fly up to nine miles in a single day.

“It was a bit surprising to find that the same pesky little lies that flit around fruit bowls and wine glasses have the capacity to navigate for many miles using the sun,” co-author Dr. Michael Dickinson told the Daily Mail.

Fruit flies – scientific name Drosophila – are about 3 to 4 millimeters long. An equivalent journey for a human would be from London to Beijing in under 24 hours, scientists said. Researchers first discovered the minuscule insects could fly such long distances four decades ago. They also knew the bugs are great navigators. But until now, they weren’t sure how they did it.

Dickinson and his colleagues at California Institute of Technology created a flight simulator to try and figure out the answer. They created a mechanism that would hold the fruit flies in place, but allow them to move their wings as if they were flying in response to visual stimulation.

They found that fruit flies have special brain cells that respond to sunlight. Using a series of LED lights, they found that the flies turned toward them and flapped. They also remembered the direction of a specific light for hours.

So they genetically modified the fruit flies’ brain cells that would make them glow when activated. Then they drilled a hole into the flies’ heads so they could watch their brains in action using magnification. They could observe the compass cells light up as the fruit flies attempted to navigate their light-based simulation.

“Insects have been navigating for many millions of years, so we think of this as a very ancient toolkit,” study first author Dr. Ysabel Giraldo said. “’Although relatively little is known about how fruit flies navigate and disperse, the availability of genetic tools for Drosophila makes them a powerful system to understand the mechanisms underlying behavior.”

The study has been published in the journal Current Biology.

By Kyla Cathey, staff writer

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