I find it really interesting to look at the range of each new moth that I observe. While iNaturalist has a lot of observations, the records are nowhere near complete, so it is not unusual to find a moth in Oklahoma that hasn't been observed here before. And about 95% of the time the other observations of that species are all to the east of us.
This is true of other living organisms, too. Due to the geographical location of Oklahoma and rainfall patterns, there is a lot of ecological transition from west to east in the state. Since many moths are closely associated with certain host plants, those moths will only be found where those plants are growing.
On a related note, many of the birds you find in Oklahoma are considered "eastern species." There are a few western species that you can find in the western half of the state, and not surprisingly, as you get farther west into the panhandle the species diversity decreases and you start to see only western species.
In the rest of this post I will give examples of some moths found in Oklahoma that don't have the typical eastern distribution.
Western Species
There are probably loads of western species that exist in Oklahoma but simply haven't been observed because there are relatively few observations west of I-35. Most of the observations we do have are by a couple of observers, Bill Carrell (@arrowheadspiketail58) and @calinsdad.
Western Tent Caterpillar (Malacosoma californica) found by @calinsdad. There are related tent caterpillars that occupy other regions of North America, Forest and Eastern Tent Caterpillars are very common.
Slave Dart (Euxoa servitus) found by Bill Carrell (@arrowheadspiketail58). This appears to be a mountain species that ranges north and south along the Rockies.
Paler Graphic (Drasteria pallescens) found by @calinsdad.
The mighty Glover's Silk Moth (Hyalophora columbia ssp. gloveri) has been spotted by @allef7 and J. D. Willson (@jdwillson) in Black Mesa State Park. This species is closely related to the Cecropia Moth (Hyalophora cecropia), which occupies the eastern half of the country.
Packard's Prominent (Elasmia packardii) found by Leah (@leahn19).
Green Broomweed Looper (Fernaldella fimetaria) found by Rick Parker (@rdparker).
Volupial Mint (Pyrausta volupialis) found by Rick Parker (@rdparker).
Fractured Western Snout (Diastictis fracturalis) that I found.
Whip-marked Snout (Microtheoris vibicalis) found by Buddy (@bothrops07).
Pale-lined Angle (Digrammia irrorata) that I found.
Orange Beggar (Eubaphe unicolor) that I found.
Some species known to occur in western Oklahoma that have not yet been observed on iNat include: :
Veined Ctenucha Moth (Ctenucha venosa)
Mesquite Looper (Rindgea cyda
Broad-lined Angle (Digrammia atrofasciata) - This species looks very similar to a common Oklahoma moth, Curve-lined Angle (Digrammia continuata). So much so, that I looked over the Oklahoma observations of this species to see if any might be misidentified. There are a couple I am hoping an expert on this genus will consider.
Signate Looper (Rindgea s-signata)
Incense Cedar Sphinx (Sphinx libocedrus)
Fulvous-edged Pyrausta (Pyrausta nexalis)
Eight-barred Lygropia (Lygropia octonalis)
Southern Species
Another range that comes into play in Oklahoma are those species south of us that reach as far north as Oklahoma but no farther. Usually these species have lots of Texas observations, but no other observations in the United States. Here are some examples:
Drasteria ingeniculata, found by Leah Nelson (@leahn19). This is an uncommon moth and a great find! There are very few iNat observations of this species, so it is hard to say much about the range, but only one observation is north of Oklahoma.
Painted Schinia (Schinia volupia), found by @lizardqueen [top] and by Tracy Pickering (@tracypickering) [bottom] There are some iNat observations of this species a little farther north and west of Oklahoma, but most of the observations are south of us.
White-tipped Black (Melanchroia chephise) found by Victor Fazio III (@vicfazio3)
Speckled Lamplighter (Lychnosea intermicata) found by Bill Carrell (@arrowheadspiketail58). There are iNat observations of this species right up to the OK-KS border, but no farther north.
Gold-striped Prominent (Hyparpax aurostriata) found by Buddy (@bothrops07). The northernmost observation of this species on iNat is about halfway between Tulsa and OKC.
There are quite a few observations of the Fawn Ruddy (Episemasia cervinaria) in the state. In fact, my neighbor Noah (@digitalnorm) has hundreds of the caterpillars devouring his hedge of yaupon holly bushes. Caterpillar photo above is Noah's; adult photo is Leah's (@leahn19). The farthest north observation on iNat is in Edmond.
Gracile Palpita (Palpita atrisquamalis) I found in Norman. This is one of the farthest north observations of the species on iNat, besides one in Utah.
Southeast Species
There are plenty of moths with a southeastern United States distribution and some of those ranges just barely clip the southeast corner of Oklahoma.
A great example is the Spanish Moth (Xanthopastis regnatrix) which was found by Troy Hibbitts (@troyhibbitts) northeast of Broken Bow. The caterpillar photo is from Troy's observation, while the adult moth is Laura Gaudetta's (@gaudettelaura) observation from Florida.
My field guide lists the Plebian Sphinx a.k.a. Trumpet Vine Sphinx (Paratrea plebeja) as being just touching the southeast corner of Oklahoma, but @claytonj_motc has observed one in central Oklahoma! Update the field guides! Eric Eaton (@bug_eric) also found one in southeast Oklahoma.
Some species known to occur in southeast Oklahoma that have not yet been observed on iNat include:
Pecan Carpenterworm (Cossula magnifica)
Black-lined Carpenterworm (Inguromorpha basalis)
Holly Borer (Synanthedon kathyae)
Northern Species
And then there are some more northern species for which Oklahoma is along the southern extent of their range. I did some searching, both looking at the range maps in the field guides, and also poking around the records in the project and this is the best example I could find.
Wild Cherry Sphinx Moth (Sphinx drupiferarum) found by Laura Murdoch (@lauramurdoch).
Oddities
Finally, I'll close out this post with some moths whose distributions are less understood.
Here is a beautiful and large Owl Moth (Thysania zenobia) found by Kayla Kamolz (@kaylakamolz) in Woodward. The range of this moth doesn't clearly fit in any of the categories above. While it has been seen over much of the United States the observations are very spotty. I just had to include it here since it is such a rarity and was found in western Oklahoma.
Here is another oddity. There are only two observations on iNaturalist of the Proud Sphinx (Proserpinus gaurae), both of which were found by Victor Fazio III in Oklahoma.
Last but not least, the ONE AND ONLY observation of White Flower Moth (Schinia bimatris) on iNaturalist was found by Paul Dennehy (@paul_dennehy) in western Oklahoma.
Stay tuned for a follow-up post regarding the "Tulsa range phenomenon."