New observations on fruit fly behavior show that these diminutive insects can show off aerial precision and agility that can rival advanced fighter jets. When evading simulated swats, the flies showed off surprisingly complex evasive maneuvers.
The latest observations were the product of a study on fruit flies conducted by researchers from the University of Washington (UW). The research team recorded footage of fruit flies using a number of high speed video cameras. To accurately capture the complex movements of the flies, the scientists set-up the cameras to shoot at 7,500 frames per second, which roughly equates to 40 frames per wing beat. The team published its findings in the online journal Science.
"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," said UW professor of biology Michael Dickinson. "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." Dickinson is also one of the co-authors of the study.
The fruit flies used in the study were members of a species called Drosophila hydei. Unlike its close cousin Drosophila melanogaster, hydei are larger and bulkier. However, they are just as capable in flight showing off sudden banking, upside down flying and even 90 degree side rolls.
"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," said UW postdoctoral researcher Florian Muijres, who is also the lead author of the study.
To pull off these impressive feats of aerial acrobatics, fruit flies have relatively advanced and high speed visual systems. The fruit fly evolved their fine tuned sense of sight to evade fast moving predators.
"The brain of the 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 added.
Given the fact that the fruit fly brain is only around the size of a grain of salt, scientists were surprised at the insect ability to pull off complex calculations in the blink of an eye. The level of complexity exhibited by a fruit fly's behavior in flight is not said to rival that of larger organisms like mice and other rodents.
"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," said Dickinson.
