Library Bug Hunt, Part 1: Mayflies and other flying insects

2009 June 27

On Monday evening, we put on another local bugs presentation at the Portage Lake Public Library[1]. After a short slide show, we showed off a bunch of bugs that we had caught in our yard, and then, we all went outside to the library’s back yard to see what we could turn up[2]. This year, I actually remembered to bring my camera, and tried to get pictures, some of which actually came out OK.[3] By which I mean, not completely unidentifiable.

The library is right next to the lake, and by luck there was a mayfly hatch going on, so I got a lot of opportunities to get pictures of mayflies.


The little guys are pretty much all wings and eyes:


I’m not sure what the function is of the long tails on the back of the abdomen, but they certainly are extensive:


Mayflies are a separate order from other insects, the Ephemeroptera. I’m not sure about the identification beyond that, although this one looks like one of the Small Minnow Mayflies, family Baetidae. Mayflies have a reputation for being short-lived, because the adults don’t have mouthparts, don’t eat, and only live for a day or two. However, this is deceptive: the larvae (which live in the water and eat organic debris that they find) actually live for an entire year, comparable to other insects. It’s just the last stage that only lasts a short time. They tend to emerge as adults all at once, because once they mature the clock starts ticking, and they have to find mates and lay eggs right away. If a mayfly emerges only a few days early or a few days late, then there won’t be anyone to mate with. When they hatch out, insect-feeding fish like trout go into a frenzy eating them, so fishermen like to hit a mayfly hatch.

There were a few other winged insects that we found at the bug hunt, like this little sooty-colored moth. There were thousands of them, all flying around a big Blue Spruce tree, but this is the only picture that came out at all (the white mesh it is resting on is an insect net, it was only maybe 8 mm long or so):


We also caught a lady beetle, that (surprise, surprise!) was not a Multicolored Asian Lady Beetle! It is evidently a Seven-Spotted Lady Beetle, Coccinella septempunctata


These aren’t native either (they were imported from Europe to control aphids), but at least they are a different non-native lady beetle species.

We also had what was evidently some sort of flower beetle, probably in the genus Hoplia. I thought it was the infamous Japanese Beetle at first, but it doesn’t quite look right for that. He got a bit abused, so I’m not sure we can get much better than that.


So, that’s all the pictures that came out[4] of bugs that had wings. I’ll stop here, and in our next installment we’ll look at the ones that didn’t have wings.

[1] We had done this last year, too, and it was so much fun that we decided to do it again. We got some collapsable cages from Bioquip, and filled them with moths and butterflies, and also brought some jars with beetles, a small aquarium with a giant water bug (which was a big hit), and Sam’s pet tarantula.

[2] We had about 85 people come this year, about twice as many as last year, and about 35 of them were kids (the rest were their parents). So there were a lot of kids out hunting bugs.

[3] Conditions were not ideal for photography with my camera; it was getting late enough in the evening that the yard was shadowed, so the light was not so good, and I was trying to take pictures of bugs that excited kids were holding in their hands, so focusing and holding the camera steady was difficult. I think next year, I’ll need some sort of platform for them to rest their hands on so it will stay steady. I should probably also ask other people to bring cameras, I just couldn’t keep up with the steady flow of bugs that they brought me all by myself. If I can con somebody into bringing an SLR or superzoom camera with a good flash, that should help a lot.

[4] I actually tried to photograph 63 different bugs, but the vast majority of them were essentially pictures of people’s hands with a little blur dashing across them.

8 Responses
  1. June 28, 2009

    Your photo is missed matched with the name of the Ladybeetle. The photo is not of an Asian Lady beetle?

  2. June 29, 2009

    Well, the ones commonly referred to as “Asian Lady Beetles” around here are Harmonia axyridis, and this one looks quite different from that – specifically, the pronotum of Harmonia axyridis is white with either four black spots or a black “W”. The one here that the kids found clearly has a black pronotum with small white spots on the sides, and a large black spot in the middle of the back, both of which I understand are more characteristic of Coccinella septempunctata. I suppose it is possible that I misidentified it, but I really don’t think so.

  3. July 5, 2009

    The mayfly has a comical look. I imagine that they still have their digestive organs, just no pathway to a mouth. Right?

  4. July 6, 2009

    Yep, they still have the digestive organs. One thing that I read said that mayflies not only don’t eat as adults, they actually pump up their digestive tracts with air. I suppose that helps them stiffen up the abdomen for better flight stability without adding weight. I suppose, in a sense, they are almost little semi-rigid airships (or would be if they pumped themselves up with hydrogen).

  5. August 26, 2009

    Is there a product out that will help stop mayflies from attaching themselves to my boathouse? We have them by the thousands when they become adults and they attach themselves to my boat, boathouse and house. You can not stay in the yard when they are hatching out, mating or whatever. HELP!!!

  6. August 26, 2009

    Bob: I don’t have any direct experience with your problem, but I did find this site that talks about outdoor lighting as being a big cause of the problem. Turning off outdoor lights during mayfly hatches is likely to help a lot. One of the things they suggest is “decoy lights”, that you put up a ways away from the things you don’t want the mayflies on, so that they will fly to the decoy site instead of to your house/boat/etc.

    On the plus side, the fact that you have so many mayflies does indicate that your water is not severely polluted. That’s good to know, right?

  7. josh permalink
    August 22, 2010

    i need help i dont know were to find mayflies and i dont live by a lake.

  8. August 23, 2010

    Josh: You should be able to find mayflies near any body of water that doesn’t dry up in the summer. If there are no lakes nearby, look for rivers, creeks, small streams, or even permanent springs. It doesn’t have to be much of a stream, we have mayflies coming out of a little stream in our yard that is only about six inches wide.

    If there is no open water at all of any kind within a few hundred yards, then you won’t find any mayflies, because they don’t really have time to fly very far from water.

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