ELi5 Why can flys see you coming a mile off when you try to swat them…but they can never seem to find their way back out of an open door?
In: 415
Flies did not evolve in an environment that had doors and windows and buildings with internal light sources. In nature, if a fly is in, say, a cave, and goes towards a source of light, most of the time it’ll end up flying out of the mouth of the cave. This doesn’t work for human-created environments like houses and apartments.
On the other hand, the environment in which flies evolved absolutely had larger predators who were trying to harm them by grabbing or swatting them with a limb. They evolved a nervous system that uses their highly effective compound eyes, which aren’t very useful for resolving details but are great at detecting motion nearby, to send a signal to their wings to fly away rapidly.
Latest Answers