Net-Winged Beetle

2008 September 27

This is a beetle, not a moth. No, really!

This poor fellow had an unfortunate encounter with a car on September 23, and I found it dead on the side of the road.

Even though it looks like a moth at first glance, it has some very un-moth-like characteristics. The orange-and-black forewings are thick and leathery, while the hindwings are membranous and transparent.

The fact that the forewings were so tough, was probably the only reason why I found it as intact as it was. The body was badly banged up (which is why I didn’t include the pictures of the whole underside), and I think that if this was really a moth, it would have ended up as an unrecognizable smear on somebody’s windshield. Thanks to the forewings, though, its otherwise mangled corpse was still in superficially good shape, and pretty recognizable[1].

It looks to me like it is the End-Banded Net-Wing Beetle, Calopteron terminale. While it does look like a moth, it evidently isn’t a moth mimic, exactly. Instead, it appears to be a case of convergent evolution. They have apparently taken up a lifestyle where flying is more important than it is for other beetles, and so their beetle-style protective wing covers (which had originally evolved from wings), are now evolving back into functional wings. They still want to tuck their wings away when not in use, but they do it the way that moths do instead of with the folding-hindwing setup that most beetles use.

An amusing point is that, while these beetles aren’t mimicking moths, they are reported to be distasteful to predators, and so some moths have kind of met them half-way, and are mimicking the beetles. Maybe one of these days I’ll find one of those moths, and we’ll have some comparison pictures.

Net-winged beetles are broadly related to fireflies (they are in the same superfamily, the Elateroidea). and they have kind of a shield structure in front of the wings that they tuck their heads under, like fireflies do. This isn’t a very good picture, but here it is anyway:

Like fireflies, the larvae live in leaf litter and under the bark of dead/dying trees, where they prey on other insect grubs. The adults fly in late summer, and eat juices from decomposing plant matter. Although, I suppose they wouldn’t turn down a bit of flower nectar if it came to that.

[1] It’s a little like the basic limitation of a bullet-proof vest, I suppose. The wing covers, like the vest, give some protection against puncture wounds. But if the wearer gets enough blunt trauma, you end up with a pulped corpse encased in some practically intact protective gear.

4 Responses
  1. September 27, 2008

    Wow, what a dramatic photo to come in on. I just popped over to see what you had posted lately and was struck by the colors of that image.

    Another triumph for the Backyard Arthropod Project!

  2. October 1, 2008

    Great photos! Interesting-I didn’t know they were related to fire flies, but now you point out the similarities…well duh!

  3. October 3, 2008

    nice catch! I’ve only ever caught a couple of those.

  4. Andy permalink*
    October 3, 2008

    Awesome photos. Cool beetle. And you found that thing in the road? I hate to think what it did to the car!

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