Mayflies--Natures Bioindicators

 

So often we as humans complain about not having enough time in our lives to get everything done that we want to. Whether it is traveling to far off places, reading those books we meant to read or spending more quality time with family, there just never seems to be enough time to get it all accomplished. Now, imagine if you will, that you are a mayfly. Mayflies, also called shadflies or Canadian soldiers, are insects in the family Ephemiperidae, a Latin name which translates into “short-lived” an apt name for these insects. As a mayfly nymph, after a long underwater existence you will rise to the surface buoyed up by the air accumulated between your first and second layers of skin. Once at the surface you will shed your outer skin (subimago) and take a maiden flight to a nearby leaf, at this time you will shed your skin a second time which results in your final adult form. Then the urgency sets in; you are now on a mission to find a mate, and lay eggs; shortly thereafter you are destined to die…all in the span of less than 24 hours. Some species of mayflies, like the American sand burrowing mayfly, have mere minutes to accomplish this feat. This truly gives meaning to making the most of the time we are given. With more than 650 species of mayflies in North America there is no shortage of species to see. They are more common in the Eastern half of the United States, with only a few species calling the Western portion of the United States home.

The lifecycle of a mayfly begins underwater as a nymph with seven pairs of gills. They live in the bottom sediment of fast-moving streams, slow moving rivers, ponds, and lakes. The nymphs feed on sediment; diatoms and several species are even predatory and feed on other aquatic insects. The presence of mayfly nymphs indicates that a water source is clean, unpolluted, and highly oxygenated. As such they are bio-indicators for healthy watery habitats. This allows environmentalists, scientists, and fisheries biologists to correct potential problems in those environments before the damage is irreversible. The subimago are a favorite food of trout and are often used by fisherman as bait. Trout fishermen also use mayflies as a model for the flies that they tie for bait. Mayflies are the only group of insects to have this subimago stage into adulthood. As a subimago they do not fly well, cannot reproduce, and lack the coloring of the adult form that would attract a mate 

 

Time is of the essence, when you only live a day or two, or perhaps only mere minutes, like the aforementioned black-brown mayfly, there is no time to waste on frivolity. Soon after mating, the female will drop her eggs upstream in the water; the current will carry the eggs downstream and deposit them on the substrate in the bottom of the stream. If the eggs are laid in lakes or ponds, she will drop them willy-nilly on top the water, and the eggs sink to the bottom.

In some parts of the world the emergence of mayflies is a remarkable sight, they all seem to appear at once in a mass exodus. Mayflies are frequently encountered at pole lights and other places well-lit at night especially in the early part of summer. In some parts of the world, hatches are so large they attract tourists from all over the world to witness the phenomena that is the mayfly hatch. In 2014 a hatch of black-brown mayflies in Lacrosse, WI was so large it was imaged on weather radar. It rose 2500 feet into the air and resembled a significant rainstorm. In areas of large emergences such as this, they quickly amass large die offs that pile up on roadways and other areas in a slippery, slimy mess, even upon occasion causing accidents. Millions of mayflies rising up out of the water in one large swarm, landing on every available surface, may seem like a nuisance to many humans, but these little insects serve a major role in the lifecycle of other species. Mayflies are not only consumed by trout and other fish, but birds, frogs, toads, other insect eating creatures get in on the all-u-can-eat buffet of mayflies as well.

Although their large numbers can be intimidating, they are completely harmless to humans. They cannot bite; in fact, they do not have fully functioning mouth parts. However, they do have stomachs, although no food will ever pass through it. Instead, it is filled will air which allows it to fly into the air in a buoyant flight pattern. This lack of mouth parts means they do not feed. Their only reason for existence it would appear is to mate, reproduce, and to be sustenance to other creatures. I did find one resource during my research that claimed they eat fruits and flowers, but in my opinion, this would be fallacy. Most likely they are sipping liquid from the fruit or nectar from the flowers. I know of no mayfly that has the ability to eat, nor do they live long enough to worry about eating even if they could.

In 1909 a woman named Lillian Bland, from Ireland was intrigued by photographs she had seen of early planes. So impressed was she by the manmade flying machines she embarked on a mission to create her own. Out of this evolved the “Bland Mayfly” the first female created aero plane. The maiden flight, in 2010, was more of a glider, and the success of this unmanned machine prompted her to mount a 20-horsepower motor on her invention and take flight. She successfully flew this plane until the middle of 2011, when her father, worried for her safety, bribed her to stop flying in exchange for a car he would give her. It appears she gave up the life of flying in exchange for a safer four-wheel mode of transportation.

 

George Crabbe, author of the poem “the newspaper” written in 1785, compared the brief life of the mayfly to the brevity of the newspaper. He waxed poetically the following:

                “In shoals the hours their constant number bring

                Like insects waking to the advancing spring

              Which take their rise from grubs obscene that lie

In shallow pools, or thence ascend the sky.

Such are these base ephemeras; so born.

To die before the next revolving morn.”

 

As summer progresses be on the lookout for the newly emerged mayflies that may pay a visit to your porch lights at night. They are delicate, beautiful creatures, and worth taking a second glance at. Keep in mind however that the mayfly you see tonight will be long gone by tomorrow night, having already left behind her eggs and the chance for future generations.