The Tiniest Insects Don't Fly, They Swim Through Air
At 0.15 millimeters long, Fairy Flies live in air that feels like syrup and row it with hairy, arm-like wings.
Kurzgesagt – In a Nutshell · What Happens If We Throw an Elephant From a Skyscraper? Life & Size 1The smallest known insects do not really fly. They swim through the air.
The insects, called Fairy Flies, are only 0.15 millimeters long, or around half a grain of salt in length. For them, air does not feel like empty space.
It surrounds them at all times like thin jelly or syrup. Moving through it is hard, and flying is nothing like elegant gliding.
Instead, they have to grab and hold onto the air. Their wings look less like proper insect wings and more like big, hairy arms, paddles for pulling themselves forward through the thick air.
Questions people ask
Why does air feel thick to something so small?
Because of how viscosity works. Air resists motion, but a large animal moves with so much momentum that the resistance is negligible. At 0.15 millimeters, momentum nearly disappears and that sticky resistance dominates, so each stroke feels more like pulling through liquid.
Are fairy flies actually flies?
No. Despite the name, fairy flies are actually a family of extremely tiny wasps. Most lay their eggs inside the eggs of other insects, and the adults are free living for only a short time. The name comes from their delicate wings and microscopic size.
Could an even smaller animal fly the same way?
Not with wings used this way. Smaller organisms, such as bacteria and many single-celled creatures, move by very different means, often with whiplike tails or by oozing. The fairy fly sits near the lower limit for an animal that rows itself through air with wings.