Selma’s mayflies have returned

Published 12:00 am Monday, August 11, 2003

They’re b-a-a-a-c-k!

Swallows return yearly to Capistrano. Buzzards fly in annually to some place in the midwest. And each year the Mayflies appear in Selma. May, incidentally, is not the only month when they emerge for their brief lifespan. Late July and early August are their favorite emergent periods locally.

Called willow bugs, a misnomer, for years, the winged insects are actually Mayflies, a member of the order of Ephemeroptera, so named because of their gauze-like wings and their short life span, beginning and ending in only a day or so or less, thus ephemeral. However, their origin dates back more than 350 million years, with about 2,100 species worldwide, including 550 in North America.

This slender, delicate insect is very soft-bodied, small to medium size and is usually found near water. Selma’s variety is commonly known as the Burrowing Mayfly, as the nymph burrows into the soft mud banks of streams and large rivers, such as the Alabama. And they often emerge from the water in enormous numbers.

To mate, thousands of males perform a kind of dance, flying up and down in great swarms, and seizing females entering the swarm, they mate in flight. Eggs are laid within an hour. Their metamorphosis is simple.

Naiads, unlike adults, have biting mouthparts and can feed. Mayfly naiads sometimes live as long as four years. Spindle shaped, they have sharp tusklike mandibles, fringed gills and fore legs adapted for digging in the muddy bottoms of rivers.The last aquatic stage leaves the water, molts and gains smoky wings. Called a dun, it soon sheds another skin to become a clear winged adult.

Friday says also that the Mayfly carries no known diseases, with the greatest problem the fishy odor as they die in large piles along the bridge and in the doorways of riverside buildings. At times, during their emergent period, the bridge becomes so slick it must be sanded. There have been years when the Mayfly population was so great that lights were dimmed or turned off in downtown Selma to prevent the problem.

According to Rudy Yates of the local Auburn University Extension Office, the Mayfly feeds on small aquatic organisms and organic debris. The last nymph molts to the winged form at the water surface, then molts once more to become adult. (It is unique among insects in undergoing a molt after the wings become functional).

Adults seldom live more than day or two and do not feed, although the Mayfly has its place in the foodchain, providing meals to many freshwater fish. Artificial flies used by fishermen are often modeled after them.

Because of plentiful rain along the Alabama this year,the Mayfly is already visiting Selma in great

number. Some have already spun their ephemeral lifespan this summer, but they will return.

They always do.