Broad-Nosed Weevil of Some Sort

2022 October 9

I found this weevil on September 11, 2022. It was in the bathroom, on the wall next to the shower. It wasn’t very active, and when I rolled it over on its back it just lay there with its legs splayed out.

It looks like one of the Broad-Nosed Weevils in the subfamily Entiminae, which is a big subfamily with hundreds of species. They are mainly distinguished by the fact that while they do have elongated faces, they don’t have the very long snouts seen in most other weevils.

Weevils mostly depend on their fairly hard shells to deter predators, so when disturbed they tend to hunker down and tough it out rather than trying to run. A lot of them, possibly including this one, even have wing covers that are fused together for extra strength, which means that they can’t spread their wings and fly.

Going through all the broad-nosed weevils on BugGuide isn’t really getting me anywhere. I can see a lot that are clearly not this beetle, but none so far that are a very good match.

Going a bit further afield, the University of Minnesota Extension Service has something that looks fairly close. Sciaphilis asperatus is the right color, the right size, has the same bulgy femurs on the legs, and has just about the same nose shape, although the back looks more humped. It is noted as being a species that is likely to get into houses in the fall, which also checks out. If this is the right one, then the larvae eat the roots of birch and maple trees (which we have in some quantity), and the adults eat the leaves of the same trees.

It sounds like they don’t get numerous enough to become forest pests, and if they didn’t regularly get into houses they wouldn’t be much noticed by people at all. It doesn’t even look like they have pictures on BugGuide yet. I should probably submit these so that they will have something in the future.

2 Responses
  1. October 16, 2022

    Something just occurred to me, a benefit of having read your blog for years. Since the weevil’s gut isn’t very long, just what are the larvae eating? Do they go after the hair roots? I would think that the woodier roots would be impossible for them to digest.

  2. October 16, 2022

    I think you are probably correct that they are going after the hair roots, followed by stripping off the cambium layer (the surface of the root, which is the only part that is actually alive). They are likely going after the soil fungi that grow in symbiosis with plant roots, too.

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