If you have been camping recently, you may have noticed the swarms of mayflies surrounding your site. Don’t worry, they will be gone very soon! An adult mayfly only has a lifespan of two days. They spend a year in the nymph stage until they sprout wings and fly into adulthood for their short-lived purpose. For about 24-48 hours, their time as adults is focused on reproducing. Some female mayflies only live for five minutes after their purpose is fulfilled.