SIOUX FALLS, S.D. (KELO) — Mayflies are back for an annual appearance at many lakes.

The aqua bug emerges from the water to find a mate and then, lay eggs, according to Entomology Today.

But when they emerge, they often do so in large numbers, or swarms, and they stink. They can clog rain spouts, cling to signs, cling to windows and porches and almost anything.

The lifespan of adult mayfly is short. Within 48 hours, they develop wings, fly towards land, mate and die, according to Michigan State University Extension.

Lake visitors and lake livers are among those who get to see the mayflies each year. KELOLAND News Chief Photographer Kevin Kjergaard found a swarm at Lake Poinsett recently.

Those who live near the Great Lakes, for example, may have their garden or home and community briefly overwhelmed with up to 88 billion mayflies, according to Michigan State University Extension.

Before mayflies become adults, they are eggs, which hatch into larvae or nymphs or naiad.

Eggs are laid in water and either settle to the bottom or adhere to some submerged object, according to Adult mayflies can lay fewer than 100 or thousands of eggs.

The larvae live in the water and eat plant material, like fish do.

Information on the mayflies agrees that while the adult mayfly is annoying, it does provide food for fish and related species.

Entomology Today even said mayfly season can be a good time to catch fish because fish are feasting on the flies.