As an entomologist with a focus on insect life cycles, I can tell you that the insect most commonly associated with a lifespan of a single day is the mayfly. Specifically, the adult stage of the mayfly, known as Ephemeroptera, is often referred to as living for a day, although in reality, their adult life can range from a few hours to a couple of days. The term "ephemeral" means short-lived, which is where the mayfly gets its name. They spend most of their life cycle in the aquatic larval stage, which can last for months or even years, depending on the species.

read more >>

Their life lasting only for 24 hours. Mayflies also called as 'one-day insects' because of their shortest life span. There are 2500 different species of mayflies in the world. In fact, some members of mayfly family die within few hours.read more >>