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Nature Notebook – Mayflies

Take a walk through a wetland in May and you might become a landing platform for an insect that looks as if it has a pair of significant stingers.

However, a mayfly’s “stingers” are thought to be used as sensory organs. Scientists aren’t exactly sure what they are sensing. It isn’t food. Adult mayflies do not have mouthparts; they don’t eat.

Mayflies aren’t using these cerci to find a mate either. Males perform a kind of swarm dance near an aquatic habitat by flying together in formation. Females recognize their species’ pattern and fly into the swarm for mating. The females then immediately deposit eggs in the water and die, as do the males.

In some aquatic habitats the mayfly adults emerge in such large numbers (the better to thwart predators) they are a bit of a nuisance but indicate the good health of that wetland.