Subject: Sexual dimorphism? Sphinx moths?
Location: Troy, VA
June 25, 2016 10:00 am
I photographed these two moths a couple of hours apart. When I looked at the photo of the second, darker moth, I realized it was definitely the same kind of moth as the first, but black and grey where the first one was white and blackish/grey. I was very excited to see such an interesting color change between the two moths. I have looked at many websites searching for these markings and the closest I have come up with is a Rustic Sphinx Moth, but really, I’m not convinced. I wonder if the difference in the moths is sexual dimorphism as I believe the dark moth to be male and the white one female. Or just the normal variety of color range in a species? I hope you find these photos as interesting as I did.
Signature: Grace Pedalino

Carpenter Worm Moth

Carpenter Worm Moth

Dear Grace,
While we agree that these are the same species, we are not convinced it is an example of sexual dimorphism, but rather, variability of tonality within the species.  Furthermore, these are NOT Sphinx Moths.  These are Carpenter Worm Moths,
Prionoxystus robiniae, a species we identified on BugGuide where it states:  “Larvae bore in wood of living deciduous trees: locust, oak, chestnut, poplar, willow, maple, and ash.”  Here is a dark individual from BugGuide and here is a light individual from BugGuide.

Carpenter Worm Moth

Carpenter Worm Moth

Location: Troy, Virginia

2 Responses to Dark and Light Carpenter Worm Moths

  1. Grace P. says:

    Thanks so much. Clearly I need to figure out how to search better, I really did spend a lot of time looking. I wasn’t convinced that it was a sphinx moth, but that seemed closest. Now I know. In any case, I thought you might like the picture of both colors.

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