What's up with bad-wing moth taxonomy?

Sorry if this is a silly question but I just realized this today and it gave me quite a surprise. I saw what I believe to be a Bad-wing Moth (Dyspteris abortivaria) and was immediately thrilled over what I thought would be my first emerald moth observation. Apparently, they’re carpet moths, not emeralds! Every other little green geometer I’ve seen around iNat has been an emerald, what makes this one so different?

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Phylogeny? It has different ancestors from another group, likely has very different genitals and already you can see it has differently-shaped wings .

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Similar color does not mean closely related.

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There is a note on the Bugguide site ( Species Dyspteris abortivaria - The Bad-Wing - Hodges#7648 - BugGuide.Net), that talks about the physical difference. The other genera/species in the Tribe are brownish. There are no links provided to taxonomic revisions. You could try to track some info down on Google Scholar (often frustratingly impossible!). The differences might be based on genitalia or genetic sequencing.

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Also just to show you there are plenty of exceptions to the rules!

Morphology, genitalia, and genetics.
“A Badwing is never an Emerald and an Emerald is never a Badwing. Green has nothing to do with it :-)”
(quote from bob patterson)

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This is a good discussion! The Bad-wing and the Emeralds are in separate subfamilies, even. BugGuide usually does not try to get down in the weeds of higher-level classification, at least on species-level guide pages. The emphasis is on field/photo ID at the species, or, failing that, the genus level. Trying to track down characters that separate those two subfamilies might be interesting, though it is likely very technical. If anyone here is able to summarize the technical literature on this, I will be happy to put it on the appropriate BugGuide pages. I wrote the original guide page for this moth back in 2004, so I feel somewhat responsible. (I had the first photo there as well, based on a slide from 1993, so I have been doing the citizen science moth ID thing for a while.)

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Ahh, so you are at fault! :grin:
I’ve never had much luck tracking down higher level taxonomic revisions. Of any group. As well, I don’t know Geometridae well at all, and it is my personal belief that the group is unidentifiable!
P.S. I find Bugguide is usually a good starting place for information. Well done.

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I did find this link - GUIDE TO THE GEOMETRIDAE OF CANADA (LEPIDOPTERA). VI. SUBFAMILY LARENTIINAE. I. REVISION OF THE GENUS EUPITHECIA | The Memoirs of the Entomological Society of Canada | Cambridge Core, although it is paywalled. Chris Schmidt (@neoarctia) may also be able to help.

I suspect this may be the case as well. The bugguide page you linked to was interesting and I appreciate that it pointed out the differences in appearance that I hadn’t noticed. Though that still leaves the question of why it’s in an entirely different subfamily, Larentiinae, instead of just being a unique emerald, or perhaps the only known species of an entire genus of odd emeralds. Genetics or Genitalia might explain that though. Thank you for the insight!

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Of course not, but this isn’t just a matter of color. Not only is the color similar, but the shape as well. Yes, there are slight differences, but I found the moth sitting in an awkward spot where it was hard to see those details at first glance, especially the unusual hindwing size. And quite frankly, I was so excited to see it that it may have clouded my judgment a little in the moment. Similar color, shape, and obviously being in the same family all lead me to the conclusion that they were in the same subfamily as well. But I suppose nature is full of surprises! :)

Adding to my comments. I have a friend who is an actual invertebrate zoologist, a specialist in moths and Odonata. He always emphasized to me that, for moths, you need to look at wing venation characters to help understand family relationships. Those are often difficult to see under all the scales, so the (specimen!) must be saturated with alcohol. Then you have to know how to interpret the pattern of veins. That takes training and experience. That sort of work is really necessary to understand the higher-level taxonomy. It is, generally, difficult to see those relationships via photographs–many rather unrelated moths look quite similar.

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I am aware how difficult it is to identify moths (specifically Noctuidae) to species. Wing veins help at higher levels, but at the species level is gets very complex. This is a reference to one genus (Euxoa), from America, north of Mexico. https://images.peabody.yale.edu/mona/27-2-ocr.pdf

If you don’t wish to plough through the 250 pages, here is a pertinent introductory quote -
“treating the large genus Euxoa whose species are frequently difficult to identify. Several factors combine to create taxonomic and identification problems: large number of species; subtle differences between species; and variability within species combined with parallel geographical variation among different species.These problems were largely overcome by the large amount of material available for study; about 200,000 specimens were examined and about 12,000 genital slides studied, almost all of which had the vesica everted, or the bursa inflated. Some species complexes, however, can be resolved only by taxonomic experiments on living material.”

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That’s really interesting, thank you for the insight! Does your friend have an iNat account?

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