Platynota rostrana and Platynota flavedana
It has come to my attention that it is only the females of Platynota rostrana that have the distinctive square shape. The males actually look more like Platinota flavedana.
Male Platynota flavedana has a tapered shape and is usually quite dark.
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Male Platynota rostrana has the shape of P. flavedana
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Female Platynota rostrana has a squarish shape.
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Here you see both a male and female P. rostrana and a P. flavedana. |
Comments
Wonderful journal entry!
@gcwarbler @annikaml @kimberlietx
Just when I think I have these figured out.... I think I'm still baffled. I thought the males with the dark area were P. flavedana, but the images on BG aren't consistent with that. And maybe the females could be separated by the antemedial line being straight or curved, but that's not consistent either. I might just roll all of these back to genus.
I want to add a link and paraphrase some comments that I came across which just expands a little more on what you pointed out.
http://mothphotographersgroup.msstate.edu/Platynota/Platynota.shtml
P. rostrana or P. flavedana males both have a costal fold (that dark edge or folded looking area around the shoulders) that is approximately 2/3 of the wing length. The short costal fold (ca. 1/3 the length of the forewing) strongly suggests P. idaeusalis.
I've read that about the costal fold, but the photos I've seen don't seem to match the descriptions consistently. Or I'm not looking at the right thing to discern the costal fold. That link also says, "The two species can be distinguished easily from each other by the scaling on the head – with a complex “hood” in rostrana (probably these), simple in flavedana" but I've never seen that illustrated, so I don't know what is being described there. I am keeping it in mind when photographing moths, but in order to get some good photos, I need to find a male that is identified as P. rostrana. That seems to be the tricky part.
I think the hood is visible from the side. I'm not sure about P. rostrana, but when I think of moth hood the first one that comes to mind is Cucullia. (I'm sure that's extreme, but it shows the tufts going backward over the head. What would be good is to find DNA verified species and compare features, but that's a rabbit hole for another day.
I do have some photos from the side, but some of these features are also visible from the angle shown here if viewed at high magnification. There are two spots that to me are possible locations for what is being referred to as a hood. If you look at the distribution of the scales, I see what I would call a collar, posterior to the eyes. On some individuals, it is a simple collar that appears as a ring around the neck. On others, it seems like the scales are oriented to the eyes rather than the anterior of the head. This results in two rings that meet at the dorsal part of what I'm calling a collar causing a sort of cowlick.
The other location would be just anterior of the point between the eyes.
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