Mayflies
Aristotle described a "peculiar bloodless animal" that emerged from near the Black Sea and perished just a day later. He named the creature the ephemeron, meaning "one-day living." Today we have another name for this insect: the mayfly. The great philosopher wasn't quite correct in saying it has a 24-hour existence, but he was close. Though mayfly youths can live from several months to several years in streams or decaying matter, their adult lives are indeed short, lasting as little as three hours for some species. As mature adults, they have only one goal — to reproduce — and with only a few hours, there's no time for romance. Mayfly sex is a forced act, with multiple males chasing a single female, and mayfly males waiting on top of young females, ready to take advantage of the moment they're mature enough to mate. These insect orgies can be so large, they can be detected by Doppler radar and can even stop traffic.