Why Are Flies So Hard To Swat?

One secret is their specialized hind wings. High-speed cameras show that flies' modified hind wings help with their speedy takeoffs.

Transcript

00:00 Why are flies so hard to swat?

00:05 A fly buzzes past your head and lands nearby.

00:09 You grab a fly swatter and you strike!

00:12 But no matter how quick you are, the fly escapes unharmed.

00:15 What is it that makes flies so hard to swat?

00:20 Flies have many adaptations that give them extra speed, maneuverability, and perception,

00:25 making them very, very good at detecting and evading your swats.

00:30 And new evidence shows that one of the ways they do that is with vibrations of stick-like

00:35 structures with a knob at the end, called halteres.

00:39 When halteres vibrate during flight, they're sensing body rotations and transmitting information

00:44 to the fly's wings, which helps flies to stabilize their bodies.

00:48 However, houseflies also vibrate their halteres while walking, but scientists didn't know

00:54 why, so they looked at houseflies and their close relatives to see if oscillating halteres

01:00 affected how the flies launch into the air.

01:03 Scientists filmed flies during takeoff using high-speed cameras, recording footage at speeds

01:08 up to 3,000 frames per second.

01:11 They found that houseflies and other closely related flies launched themselves around five

01:16 times faster than other flies, and with just one wingbeat.

01:20 When scientists removed those flies' halteres, it took them longer to take off, and some

01:26 took a nosedive and crash-landed.

01:29 But halteres aren't the only secret weapon in a fly's evasive arsenal.

01:33 Fruit flies can change course in under 1/100th of a second, about 50 times faster than an

01:39 eye can blink.

01:41 Flies also have exceptional vision, which helps them react to a threat and adjust their

01:45 trajectory within milliseconds before takeoff.

01:50 With all these built-in advantages, it's no wonder that the fly you're trying to

01:54 swat can easily escape and just buzz off.

02:00 Aerodynamic flies.

02:02 Just another one of life's little mysteries.

02:04 (record scratches)