Big Sawfly and Flower Longhorn

2015 September 19

As we were beach-hopping down the east coast of the Keeweenaw Peninsula on July 12, 2015, we found these two specimens. The first is similar to one that we’ve seen before – the enormous Elm Sawfly.

But, while this one does look to be one of the big Cimbicid sawflies, it doesn’t have the prominent white spot between the wings that the Elm Sawfly has.

It’s a shame there’s no white spot, because now I don’t know which one it is. Thre are twelve known north american species in the Cimbicid family, and BugGuide only has pictures for about half, so I don’t know which one this might be.

It’s got a pretty good set of mandibles, in any case, although it didn’t show any inclination to bite me.

The second specimen is one of the many kinds of flower longhorn beetle that we have around. They are commonly found as adults rummaging for pollen and nectar in flowers.

I’ve got a good view of the pattern on the wings, and I think it is most likely the widespread Judolia montivagans.

Like other longhorn beetles, their larvae probably live in dead or dying wood. I don’t know if this particular species is one of the ones that can kill trees or not.

I’m not sure anyone else knows, either – there are some 200 species of flower longhorns, and it looks like most of them haven’t had their larval host plants determined yet. I managed to google the relevant pages from “The Cerambycidae of North America”, by Earle Gorton Linsley and John A. Chemsak, and all they have to say is that some members of the Judolia genus eat pine as larvae, although this may not be universal. We do have a lot of pine around, though.

3 Responses
  1. September 19, 2015

    Man, that sawfly looks mean.

  2. Carole permalink
    September 19, 2015

    Have that sawfly larvae are a favorite of bluebirds.

  3. September 20, 2015

    KT: Since he didn’t try to defend himself with them, and sawflies aren’t carnivorous, I expect that they use those scary-looking mandibles for some other purpose. Maybe the males use them to fight with each other.

    Carole: Unfortunately, we only rarely see bluebirds up here.

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