The Shortest-Lived Insect: Mayfly Larvae - Apparently.
Mayfly larvae, also known as nymphs, live for only about 4-5 minutes in their aquatic stage before they emerge as winged adults. This rapid life cycle is likely an adaptation to avoid predators that target them in the water. Adult mayflies have a relatively short lifespan as well, with most living for only a few hours to a few days. Despite their brief lives, mayflies undergo four distinct life stages, including egg, nymph, adult, and sometimes a dormant stage called an "insect quiescence".