Naturespeak A naturalist's view of the world

June 30, 2011

Mayfly Overload

Filed under: Uncategorized — wykes @ 9:02 pm

Summer is no longer young. The wheat fields are ripening, the baby woodchucks are getting fat, the bombs will soon be bursting in air (fireworks that is), and the mayfly hatch is peaking. The big annual hatch here is composed of the large Burrowing, or Yellow, Mayflies of the genus Hexagenia. On warm muggy evenings, the aquatic creatures emerge from Lake Erie by the millions and end up covering nearly every lakeside home, storefront, or sign by the dawn’s early light.

It is not my intention to address the details of the hatch this season. Last year, for the sake of the story, I allowed myself to be covered by thousands of mayflies (a stunt I will probably not do again for some time or possibly never). This year I wanted to call attention to the sheer bounty of food stuff provided by the hatch. I will not grill up a mayfly patty, although I’m sure such a thing would be possible, but I can point out that there are hundreds of pounds of biomass out there – both live and dead food.

To review, the “flies” emerge as reddish sub-imagos (see above). These creatures spend the better part of the following day resting. They then shed their skins one more time before flying off to participate in the following night’s orgy. The empty skins remain for a week or so, but the insects themselves die within 48 hours.  But, oh, they are everywhere during that time.

Every insect eating entity is faced with a flood of wingy lake-bred goodness. Birds have especially taken up the feast. Kingbirds, Swallows, and Red-winged Blackbirds all have been seen stuffing their beaks with mayflies. Most are taking them to feed the kids. I came upon one Robin (see beginning photo) whose beak was packed with no fewer than 6 large mayflies – possibly more. It is a wonder how this bird, and others like it, can manage to grab so many “flies” without losing the ones already in tow (it’s like picking up firewood). I do think this bird had reached the limit by the time I snapped her photo.

I have noticed that during an especially big hatch year, birds will eventually grow sick of them. There must be something like a “Mayfly Brain Freeze” that occurs. They will spend less and less time pursuing them until finally ignoring them altogether. If it weren’t for the responsibility of feeding their young, they probably wouldn’t grab them at all (“You will eat this and you will like it! It is good for you”).

Orb-weaving Spiders are forced to deal with the massive onslaught of mayflies. For most, the whole thing is a night mare. They lay out their carefully constructed nets and wait to see what blunders in.  They are powerless to control the process. Mayflies are big insects and when they blunder into the net they tend to rip it asunder. A whole ton of blundering “flies” will rip a web to snot in no time and leave the weaver weeping from each of its eight tiny eyes. While Shamrock and other larger arachnids could probably take a few of the mayflies as food, the rest are forced to wait them out and repair the damage afterward (only to have it re-destroyed on the very next night). From a human perspective, a dead mayfly in a spider web is a thing of geometric beauty (see below) regardless of what the spiders think about it.

When it comes to mayflies, the truth is that most of the creatures end up dying on their own. Untouched by predatory mouths of any sort, they fall to the ground and pile up or drift silently on the surface of the water. As most locals are well aware, these aggregations of dead insects can be quite smelly. This is really the only negative part about the hatch, but it is enough to get some folks to twist their underwear into seasonal knots over it. Fear not, there are many more creatures cleaning up the dead ‘fly bonanza. They can never keep up to the over-supply, but do their part none-the-less.

Take the example of the lone black ant I spotted carting a dried mayfly off to some unknown destination (see above and detail here). In fact, I’m not sure the creature really knew where he was going, although it was a monumental task just to move the carcass at all. I figure it would be like you or I carrying a sofa or, in order to keep this a food comparison, like hauling a giant taco the size of a sofa.

The burrowing Mayfly season is a short time, but it is a season of plenty for all creatures great and small. Some like it, some hate it, but all deal with it.


1 Comment »

  1. brain freeze is always cause by the dilation and contraction of the blood vessels during temperature changes.”

    Go look at our new web blog too
    <a href="

    Comment by Renaldo Mcquarrie — January 8, 2013 @ 8:50 am

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress