What's That Bug? does not endorse extermination

Subject: Red-Spotted Purple AND Western White Admiral!
Location: Naperville, IL; Grand Teton, WY
August 19, 2013 8:57 pm
Dear Daniel~
I know you dislike it when folks send photos of two different species in one submission, but as these are actually two different *sub*species, and one led me to the other, in effect, maybe you’ll forgive me?
I was so happy this morning because I saw a flash of what I initially thought was my garden-variety Black Swallowtail butterfly (I think we don’t have Pipevine Swallowtails around here) when I noted the lack of distinctive Swallowtail hindwings. I have never seen a Red-Spotted Purple in my yard before, so you can imagine how excited I was.
Then, later on this evening in the course of finding the scientific name for the Red-Spotted Purple, I discovered that a butterfly I photographed (badly, I might add, but it was flitting around so quickly) last week in Grand Teton National Park and was struggling to identify was none other than a Western White Admiral, a different form or subspecies of Limenitis arthemis, my beloved Red_Spotted Purple.
How thrilling!
I hope you have a wonderful evening!
Signature: Dori Eldridge

Possibly Weidemeyer's Admiral

Possibly Weidemeyer’s Admiral

Hi again Dori,
We are not fully convinced that this is a White Admiral, which BugGuide lists as inhabiting the Northeast, and reports it as far west as Wisconsin.  Another possibility is the Western White Admiral, yet another subspecies,
Limenitis arthemis rubrofasciata, which BugGuide reports from Canada and bordering Montana.  This is a slightly redder subspecies, but your individual is not a freshly emerged adult and it is showing some wear, tear and fading.  Our money is actually on Weidemeyer’s Admiral, Limenitis weidemeyerii, which BugGuide actually reports from Wyoming.  It is described on BugGuide as being:  “Above, black with a wide white postmedian band on both forewings and hindwings. Below, forewing is black with white band and white spots inside band. Hindwing is blue-grey with black cross lines inside the white band and a variable row of reddish spots inside a row of blue-grey crescents outside the white band.”  If you had a photo of the underside, it would perhaps be more conclusive, but to further complicate the identification, according to BugGuide, the Western White Admiral:  “Hybridizes or perhaps intergrades with L. lorquini & L. weidemeyeri where they meet to the southwest in ne. Washington, w. Montana, n. Idaho, British Columbia, and sw. Alberta. Not all specimens in this region will fit neetly into one or another species, but will be intermediate in character. Blends with subspecies astyanax southward on Prairies (and, if eastern populations are the same, blends with subspecies arthemis southward in Great Lakes region and east through New England).”  BugGuide does also have a map range for the various subspecies of Limentis arthemis, and it does not include Wyoming, which is further support of our belief that this is most likely Weidemeyer’s Admiral.  Perhaps you also have a view of the undersides of the wings which would lend further proof to our supposition. Willow is listed as a food plant for all the species and subspecies we have mentioned, and it appears that your individual is hovering around a willow, possibly to lay eggs.  All of our waxing on the identity of this lovely butterfly is further reason to split it off into a separate posting from your Red Spotted Purple.

Hi Daniel!
Wow! Last week, with my very limited Internet, I was vacillating between a Lorquin’s Admiral and a Weidemeyer’s Admiral as an ID for this B&W butterfly! When I read an older post on your site last night about the three subspecies of Limentis arthemis, perhaps I became too excited at how coincidental it was, having spotted the Red-Spotted Purple yesterday. I am certain you’re correct, and yes, the butterfly was flitting in and out of the willows along the edges of Jackson Lake in Colter Bay, likely laying eggs, as there were no flowers around from which she could have been feeding, other than musk thistle. I was having a difficult time focusing my camera on the butterfly, as opposed to all the surrounding willow leaves, so this is actually the only shot I have of it that is completely unobscured. A very interesting side note about the Yellowstone/Grand Teton ecosystem in which willow plays a big part: the reintroduction of wolves has had a large, positive effect on the wildlife that rely upon willow as food. The roaming, preying wolves have caused the huge elk population to become more wary, forcing them out of complacency and away from the willows they had formerly been decimating. This in turn saw a resurgence of willows along water’s edge, along with the fauna that have historically fed upon it, particularly beavers. Thank you so much for sharing your enormous expertise and passion! I can’t say enough wonderful things about you and your fabulous, fabulous web site!
All the best,
-Dori Eldridge

Thank you for your kind comments Dori, and also for that wonderful information on the wolves.

What's That Bug? does not endorse extermination
Location: Grand Teton, Wyoming

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