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You’ve probably heard that mayflies live for only a day, but that’s not the whole story. Depending on how you measure it, their lifespan is both longer and shorter than that.
Although it’s true that mayflies have notably short lives as adults, they actually spend a year or two underwater as nymphs after emerging from eggs in the riverbed. Incredibly, once they leave the water as winged, flying adults, time has almost run out.
Though there is some variation in lifespan among mayfly species, females of the American sand-burrowing mayfly (Dolania americana) species, native to the southeastern United States, have just five minutes to live as adults. And there’s not a moment to waste, as they must find a mate and lay eggs in the water before they expire. Males of the species have around an hour to live, which they spend finding females to mate with.
While other mayfly species live slightly longer, it’s common for their adult lifespan to be 24 hours or less. Adult mayflies typically lack mouthparts and digestive systems, so they obviously don’t waste time eating, instead living off energy stores built up during the larval stage. Reproduction is the sole focus of their adult lives. This is especially evident in the anatomy of female mayflies, whose bodies are filled with thousands of eggs (another reason why they don’t have space for a digestive system).
Long live the mayfly:
- What mayflies lack in lifespan, they make up for in numbers. A mayfly swarm can consist of millions of individuals suddenly emerging from a stream or river.
- Mayflies belong to the group Ephemeroptera, which fittingly means “short-lived flyer.”
- Though they have been on our planet for around 350 million years, ancient mayflies have much in common with those we see today.
- Large mayfly populations often indicate a clean aquatic habitat, while a lack of mayflies may indicate pollution.
- If you consider its entire life cycle rather than just its adulthood, the seven-figure pygmy goby (Eviota sigillata) is more deserving of the “shortest lifespan” title. Native to tropical waters in the Pacific Ocean, these common fish have a complete life cycle of around two months. They spend three weeks as larvae, mature on a reef for one or two weeks, and then enjoy their brief adult lives for a maximum of three more weeks. They are the vertebrates with the shortest lifespan.