2014 August 20

Our friend Bob was visiting the area on July 4-7, 2014, and was staying in Centennial (about 12 miles north of our house) when he spotted this very large insect on the wall of his cabin. And being the thoughtful fellow that he is, he took these photographs and sent them to me.

And here it is with a penny for a size reference.

It has the feathery antennae that we’ve come to expect from male insects that locate their mates by scent.

At first I thought it was a dobsonfly, but male dobsonflies have huge mandibles, and this one didn’t.

It is related to the dobsonflies, though. It’s actually a Fishfly, of which there are two species known in Michigan. I think it is Chauliodes pectinicornis   (the Summer Fishfly) based mostly on the time of year, and also the coloration of the spots at the back of his head.

Dobsonflies and fishflies (along with the alderflies) used to be considered part of Neuroptera, along with the ant lions and lacewings, but recently they’ve been spun off into their own order, the Megaloptera. All the members of this order have aquatic larvae, which come onto land to pupate and emerge as adults that live for a week or less. The nearest body of water to where this fishfly was found is “slaughterhouse creek”, so I expect that’s where it came from (they like ponds and slow-flowing streams for their larvae).

Since fishflies are big, their larvae are big too, and poking around I find that they look fairly threatening (they are omnivorous, and are more than happy to eat things like tadpoles when they catch them). They look pretty similar to the larvae of the dobsonflies, which are commonly called “hellgrammites” and are sold as fishing bait. I kind of expect that if you go and buy some hellgrammites from the bait shop, they might be either dobsonfly or fishfly larvae. Not that the fish will care, of course.

One Response
  1. August 22, 2014

    Very cool. I have, very rarely, found fishfly larva when conducting macroinvertebrate sampling as a Missouri volunteer water quality monitor, but had NO idea what the adult looked like. Thanks.

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