It’s interesting to note that insects were the world’s very first flyers in history, in fact insects took to the skies even before birds, bats and pterosaurs, allowing them to discover new habitats and establish themselves as the most diverse animal class today.
While evolutionary biologists are still baffled about the evolution of flying insects, the lack of fossil evidence doesn’t help.
According to Floyd Shockley, an entomologist at the Smithsonian’s National Museum of Natural History, there are two competing hypotheses, you can decide which one you believe,
The “tergal hypothesis” which suggests that wings originated on the tergum — the top of the insect body wall — perhaps as gliding membranes.
The “pleural hypothesis” argues that wings were created from ancient leg segments that merged with the body before ending up on the back.