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Μάρτιος 14, 2019

Confusing Yellow Pyraustines Demystified

The purpose of this post is to demystify the “confusing yellow Crambids” in the subfamily Pyrausinae in the United States and Canada. This is a group of moths with some difficult-to-identify species, but many are identifiable based on photos alone if you know what to look for. The species and genera discussed here are:
Hahncappsia spp
Helvibotys spp
Neohelvibotys spp
Crocidophora tuberculalis
Ecpyrrhorrhoe puralis
Paracorsia repandalis
Anania labeculalis
The first three genera are closely related and contain some extremely similar species. The last three species are superficially similar to the species in those genera, and appear to be commonly confused with them online.
Virtually every online moth ID platform has a history of major misidentifications of all these species. BugGuide was a mess until I sorted through their photos in 2017, MPG had lots of misidentifications until it was updated in 2017, and BAMONA still has quite a few misidentifications in this group as of March 2019. The first thing to look at when trying to place these species is the st line on the forewing. The following characteristics can help start the ID process:
Hahncappsia spp: Most have an st line present, but it can be faint. When present, it is always straight, not curved to parallel the terminal edge of the forewing. H. fordi and H. alpinensis, both species found exclusively in the Southwest, are very plain and lack st lines entirely, making them look more like Helvibotys spp than like other Hahncappsia.
Helvibotys spp: no st line present
Neohelvibotys spp: no st line present
Crocidophora tuberculalis: A native species to most of the East with a bold, thick, dark st line that is curved so it parallels the terminal edge of the forewing. This should make this species unmistakable. The males of this species also have a scaleless crinkled fovea on the forewing, which isn’t seen in any other species treated here. Here’s a male with the crinkled fovea: https://www.inaturalist.org/observations/18384692 And a female without it: https://www.inaturalist.org/observations/20497923
Ecpyrrhorrhoe puralis: a large bright yellow species introduced in the Southeast with faint markings overall, the st line being curved when present, but often not visible. Here’s a well-marked one: https://www.inaturalist.org/observations/4041567 And a poorly marked one: https://www.inaturalist.org/observations/817257
Paracorsia repandalis: a dull species introduced in the Northeast and upper Midwest with a curved st line, and thick smooth pm and am lines. Here’s a typical one: https://www.inaturalist.org/observations/12281430
Anania labeculalis: a southwestern species with a faint, thin, wavy st line. The lines on this species are all generally very thin and quite dark, and it can be easily separated from Hahncappsia in the area by its complete PM line on the hindwing, reaching the inner margin. Look at the visible pm line on the hindwing here; no way this should be mistaken for a Hahncappsia: https://www.inaturalist.org/observations/868592
Once you’ve eliminated A. labeculalis, E. puralis, P. repandalis, and C. tuberculalis for your moth, there are a few “easy” to identify Hahncappsia and Helvibotys you can check.
Distinctive species:
Hahncappsia coloradensis: this is a big white species of the interior mountain west and western plains, with dark brown scaling near the costa and around the reniform and orbicular spots, which looks like this: https://www.inaturalist.org/observations/16683451
Hahncappsia mellinialis: This species is bigger than any other treated here, is brown, is only found in mountains in Arizona and New Mexico (maybe west TX too?), and is more likely to be confused with an Ostrinia than a Hahncappsia. Here’s a typical specimen: https://bugguide.net/node/view/1299446/bgimage
Helvibotys pucilla, Helvibotys freemani, and Helvibotys subcostalis: these look nothing like any of the other species treated here, and can be viewed on MPG.
If you don’t have one of these “distinctive” species, placing your moth to genus gets a little trickier. This is generally what I look for:
Hahncappsia: Usually have more wavy pm lines on the FW than Helvibotys and Neohelvibotys. Other than alpinensis and fordi, usually have at least a trace of an st line on the forewing. Here are some typical Hahncappsia specimens: https://www.inaturalist.org/observations/9457573 https://www.inaturalist.org/observations/14577667
Helvibotys and Neohelvibotys: usually have smooth and very bold pm lines on the FW, and never have an st line. Here’s a typical specimen: https://www.inaturalist.org/observations/14137388
Hahncappsia alpinensis and fordi are two “non-typical” Hahncappsia that look like this: https://www.inaturalist.org/observations/19012350 The forewings look more like Helvibotys than Hahncappsia, but note the almost complete lack of markings on the hindwings, and note how faint the markings are compared to a real Helvibotys/Neohelvibotys like this: https://www.inaturalist.org/observations/14845820. H. alpinensis and fordi are best separated by genitalia where they both occur, from Arizona to west Texas. In Southern California and Nevada, only fordi occurs, and in most of Texas, only alpinensis occurs, so in many cases they can be ID’d by range.
If you have a “typical Hahncappsia”, these are your options:
In the East, you could have pergilvalis, mancalis, marculenta, neomarculenta, or neobliteralis. In the Southwest, you could have pergilvalis, mancalis, huachucalis, jaralis, pseudobliteralis, or cochisensis. In peninsular Florida, you likely have H. ramsdenalis: http://v3.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=341792
Hahncappsia mancalis: This species has the boldest and most complete st line of any of the typical Hahncappsia species. It also tends to be more tan in color (less yellow) compared to the other options. Here’s a typical example: https://www.inaturalist.org/observations/14680897
Hahncappsia pergilvalis: This species is generally paler in its base color than the others it occurs with, and its st line is usually splotchy and broken in the middle, like this: https://www.inaturalist.org/observations/16683448
Hahncappsia marculenta/neomarculenta/neobliteralis: this is the trio of eastern yellow species that is the most difficult to separate in photos. Marculenta is by far the commonest of the three, but the others are equally as widespread. Here is a typical example: https://www.inaturalist.org/observations/10186526 This species group is only differentiable based on genitalia, and specimens that have not been dissected should never be identified to the species level.
Hahncappsia huachucalis: This species is abundant in the mountains of southeastern Arizona, but doesn’t occur outside that region in the US. It’s a pretty spectacular-looking rusty brown species that isn’t easily mistaken for others in the genus in good condition: https://www.inaturalist.org/observations/10869666 It’s the most common Hahncappsia in the Chiricahua Mountains.
Hahncappsia jaralis/pseudobliteralis: This pair is the southwestern equivalent of the eastern marculenta/neomarculenta/neobliteralis group, and is also best separated based on dissection. Here is one of each that I dissected: https://bugguide.net/node/view/1457763/bgimage and https://bugguide.net/node/view/1457757/bgimage
Hahncappsia cochisensis: This is the only Hahncappsia species in the US that I haven’t personally encountered, so I can’t make many generalizations about it. It appears to be a pale yellow species with white hindwings found in southeastern Arizona: http://v3.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=287890 The plain white hindwings seem to be diagnostic.
If you have a typical Helvibotys/Neohelvibotys, then consider the following options:
In most of the East, if your moth has a dark terminal band, like this: https://bugguide.net/node/view/1422376/bgimage then you have N. neohelvialis. If your moth lacks this, and is a bit smaller, then you likely have H. helvialis, shown here: https://bugguide.net/node/view/528994/bgimage
In the Southwest, then the large ones with the dark terminal band are N. arizonensis, shown here: https://bugguide.net/node/view/1441697/bgimage, while the small ones without it are likely to be H. pseudohelvialis: https://bugguide.net/node/view/1457768/bgimage
The only other species that throws a wrench in things is N. polingi, a Neohelvibotys that lacks the dark terminal band like a Helvibotys and is found from Florida west through Texas (possibly also SE Arizona?). If you’re in the Deep South, you’ll likely need to dissect your Helvibotys-looking specimens to distinguish between the two Helvibotys species and N. polingi. Here’s a N. polingi specimen: https://www.inaturalist.org/observations/6809500
Hopefully this post provides enough information to determine which of these yellow Pyraustines are identifiable from photos and which are not. There are a lot of species involved in this group, but most can be identified if you know what to look for.

Αναρτήθηκε στις Μάρτιος 14, 2019 0242 ΠΜ από paul_dennehy paul_dennehy | 5σχόλια | Αφήστε ένα σχόλιο

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