Insects first appeared around 400 million years ago, long before mammals or flowering plants. Even before dinosaurs.

Then, around 315 million years ago, they were the first creatures to learn to fly.

Insect wings are actually the most durable part of their body, and the most likely to appear in the fossil record, giving us a pretty good idea of insect development.

Their size increased in direct relation to the amount of oxygen in the atmosphere. Once oxygen hit 30 percent—9 percent higher than today—the largest insects had wingspans over 2 ft!

Around the same time, avian dinosaurs developed, and large insects were easy prey—to survive, they became smaller, faster, and more agile.

Dragonflies developed speed; they’re able to hit 35 miles an hour but have the most primitive kind of wing.

Flies developed maneuverability; their shorter, folding wings allow them to dart into small openings.

Other insects evolved new uses for wings. The front wings of beetles became hard covers, to protect them from predators or while burrowing.

The wings of some moths became camouflage, to blend into specific environments. Butterflies developed brightly colored wings to attract mates or to warn enemies they’re poisonous.

Grasshoppers and crickets can even use their wings to fill the air with sound.

We tend to take winged insects for granted or consider them a nuisance. But next time you see a dragonfly hunting mosquitoes or hear a cicada sing, you’re witnessing evolutionary biology hundreds of millions of years old.