When startled by a predator — including a swatter-wielding person — tiny fruit flies respond like fighter pilots, employing screaming-fast banked turns to evade attacks, according to a new study.
The slick move was evident in the study, published in the latest issue of Science, since researchers used an array of high-speed video cameras operating at 7,500 frames a second to capture the wing and body motion of flies after they encountered a looming image of an approaching predator.
“Although they have been described as swimming through the air, tiny flies actually roll their bodies just like aircraft in a banked turn to maneuver away from impending threats,” co-author Michael Dickinson, a University of Washington professor of biology, said in a press release.
He added, “We discovered that fruit flies alter course in less than one one-hundredth of a second, 50 times faster than we blink our eyes, and which is faster than we ever imagined.”
In the midst of a banked turn, the flies can roll on their sides 90 degrees or more, almost flying upside down at times, according to co-author Florian Muijres.
“These flies normally flap their wings 200 times a second and, in almost a single wing beat, the animal can reorient its body to generate a force away from the threatening stimulus and then continues to accelerate,” Muijres explained.
The fruit flies are about the size of a sesame seed, so they are not exactly known for impressive brain size. But consider that big bodies need larger brains to control everything. A small brain simply has a smaller body to control. It doesn’t necessarily mean that the species is a dummy.
Houseflies also plot and plan clever escapes. You can see this at work in slow motion in the following video:
“The brain of the (fruit) fly performs a very sophisticated calculation, in a very short amount of time, to determine where the danger lies and exactly how to bank for the best escape, doing something different if the threat is to the side, straight ahead or behind,” Dickinson said.
He continued, “How can such a small brain generate so many remarkable behaviors? A fly with a brain the size of a salt grain has the behavioral repertoire nearly as complex as a much larger animal such as a mouse. That’s a super interesting problem from an engineering perspective.”
In the future, he and his team would like to investigate how the fly’s brain and muscles control the remarkably fast and accurate evasive maneuvers.
(Image: F. Muijres and F. van Breugel, University of Washington)