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? A fly buzzes past your head and lands nearby.
00:08 You grab a fly swatter and you strike! But no matter how quick you are, the fly
00:13 escapes unharmed. What is it that makes flies so hard to swat? Flies have many
00:21 adaptations that give them extra speed, maneuverability, and perception, making
00:25 them very, very good at detecting and evading your swats. And new evidence
00:30 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. When halteres vibrate during
00:40 flight, they're sensing body rotations and transmitting information to the flies
00:44 wings, which helps flies to stabilize their bodies. However, house flies also
00:50 vibrate their halteres while walking, but scientists didn't know why. So they
00:55 looked at house flies and their close relatives to see if oscillating halteres
00:59 affected how the flies launch into the air. Scientists filmed flies during
01:04 takeoff using high-speed cameras, recording footage at speeds up to 3,000
01:09 frames per second. They found that house flies and other closely related flies
01:13 launched themselves around five times faster than other flies and with just
01:18 one wingbeat. When scientists removed those flies' halteres, it took them longer
01:23 to take off, and some took a nosedive and crash-landed. But halteres aren't the
01:29 only secret weapon in a fly's evasive arsenal. Fruit flies can change course in
01:35 under 1/100th of a second, about 50 times faster than an eye can blink. Flies also
01:41 have exceptional vision, which helps them react to a threat and adjust their
01:45 trajectory within milliseconds before takeoff. With all these built-in
01:51 advantages, it's no wonder that the fly you're trying to swat can easily escape
01:55 and just buzz off. Aerodynamic flies, just another one of life's little mysteries.