More on Butterfly Names – Pajarito Environmental Education Center

More on Butterfly Names – Pajarito Environmental Education Center

© Steve Cary, November 2024


Successful discovery and photographic study of a colony of Ellis’ Blue (Euphilotes ellisi) shows to nail down the rest of our dotted-blues (Euphilotes spp.), by Steve Cary. Ellis’ Blue has been a bit of an enigma in New Mexico. There have been several documented, confident sightings, of Euphilotes ellisi anasazi (our subspecies) in northwest NM. Its larval host is known to be Crispleaf Buckwheat (Eriogonum corymbosum). And the bug has been described/characterized elsewhere (southwest Colorado), so it is possible to go into the field with an idea of where to look and what to look for in terms of hostplants, behaviors and wing characters. [You can see the observations that are discussed in this story by going to iNaturalist, click Explore, then specify Ellis’ Blue; the “where” is Sandoval County, NM. If you remove all filters and deactivate “needs ID,” you will see the cluster of observations in the vicinity of Torreon. You can repeat that process for Crispleaf Buckwheat.]

So, what’s the problem? Well, first, I am not a botanist and there are 250 confusing species of buckwheats; which one is corymbosum? And second, there are several species of dotted-blues that all look about the same and fly in the same area at about the same time; their distinguishing marks can overlap with each other. It is not difficult to go out in August and find a good buckwheat patch with dotted-blues cavorting about. But my lazy habit of simply getting a bunch of ventral photos, no matter how fine, simply does not provide enough information to confidently distinguish the dotted blues. If that’s the problem, then what is the solution? I think the solution revealed itself this last August . . .

In August 2022, Christopher Rustay was in the field near Torreon in western Sandoval County, where he photographed a butterfly and a buckwheat; he submitted his images to iNaturalist (obs. 133087065).

More on Butterfly Names – Pajarito Environmental Education Center
unknown blue (maybe Acmon or Lupine) near Torreon, Sandoval Co., NM; August 28, 2022 (photo by Christopher Rustay).

Christopher had included two pics of the butterfly showing the underside. Having never knowingly seen a dotted-blue, he suggested via iNat it might be Lupine or Acmon Blue, but was confident only that it was a blue of some kind. His observation languished for almost a year, but in July 2023, Joshua C’deBaca identified it as a dotted-blue (genus Euphilotes). Then it caught my eye, and I agreed it was a Euphilotes, or dotted-blue, but I opined that it might be difficult to make a confident ID to species from only the two images that were available. It could be centralis, rita coloradensis, ellisi or even pallescens and the getting plant IDed would be key to identifying the butterfly.

wild buckwheat (Eriogonum sp.) growing where the dotted-blue was seen; near Torreon, Sandoval Co., NM; August 28, 2022 (photo by Christopher Rustay).

With passage of another year, in early August 2024, Joshua and Mike Shoop were keen to track down some of my old Euphilotes records from Sandoval County. While making some specific suggestions of what to look for and where, I also suggested they investigate the place near Torreon where Chistopher had been back in August 2022. They located the spot on iNat, went there, and Mike S. reported as follows on August 16: “We found a very large stand of E. corymbosum (both Joshua and I felt confident on the species) we found . . . Euphilotes on the corymbosum that looked more like Ellisi. . . . An added benefit was Mormon Metalmarks that were nectaring there, a life butterfly for Joshua.” Among the images that Mike S. submitted to iNaturalist (obs. 236174827 and others).

female maybe Ellis’ Blue (Euphilotes ellisi?) near Torreon, Sandoval Co., NM; August 16, 2024 (photo by Mike Shoop).

The snowball grew from there. Mike S. put some butterfly underside images on iNat; they were helpful and consistent with Ellis’ Blue. He did his best to get dorsal views, but these blues do not always cooperate, and he got partial views of a female upperside, but still we needed more. I went there myself on 8/22 and was very fortunate that after 2 hours of searching, a male decided to show what he had. But I was unable to snap any females.

Ellis’ Blue (Euphilotes ellisi) male near Torreon, Sandoval Co., NM; August 22, 2024 (photo by Steve Cary).

The very next day, Mike A. posted to iNat a huge raft of images of the blues at that site. If you want to know what this butterfly looks like, male and female, dorsal and ventral, and how it behaves, courts, mates and oviposits, you need look no farther than Mike A’s rich images, especially of females. Said Mike A.: “I got on to the Torreon colony because Chris Rustay and Mike Shoop posted iNat records from 28 Aug 2022 and 16 Aug 2024, respectively. Truth is, I have tried to find your locality “6 miles west of San Ysidro Pueblo on Hwy 550″ without luck the past couple of years, so it was welcome news that Torreon materialized as an easy spot for ellisi.”

Ellis’ Blue (Euphilotes ellisi) female near Torreon, Sandoval Co., NM; August 23, 2024 (photo by Mike Andersen)

At about that same time, Christopher back-tracked to his initial buckwheat observation submitted to iNat in August 2022. It turned out that, as luck would have it, back in December 2022, a professional botanist had reviewed the observation (buckwheat: obs. 132750518) and identified it as Crispleaf Buckwheat. Thus, all plant IDs pointed firmly at Crispleaf Buckwheat, closing that loop as well.

It took a couple of years for this story to ripen to a firm conclusion about the plant and the butterfly. It seems like a long time, but considering that it was done only with photos and iNat submittals, I consider that a terrific accomplishment. Heck, we now know how Ellis’ Blue, subspecies Anasazi, actually looks! It will help us know when we see it elsewhere in NW NM. That is significant and it was a community effort!

Even better, we now have a formula for getting the same outcome for other buckwheat patches and their dotted-blue colonists. These are the steps:

  1. Identify a nice patch of a wild buckwheat species that hosts a dotted-blue.
  2. Get the buckwheat identified as confidently as possible; professional botanist recommended.
  3. Photo-document the details of the dotted-blue, including clear views of male and female, dorsal and ventral, of multiple individuals.
  4. Come back a month later and photograph larvae.*

Given the vagaries of life, weather, climate, busy schedules, etc., this process could take a couple of years for any particular stand of buckwheats, as it did for the Torreon colony. That’s OK. We’ve been waiting decades; another year here and there is not a problem. I particularly recommend we target:

  1. additional stands of E. corymbosum to further define the geographic distribution of Ellis’ Blue in NM;
  2. stands of E. leptocladon to further define the appearance and distribution of Pallid Blue (Euphilotes pallescens) in NW NM; and
  3. stands of E. effusum to further define appearance and distribution of ‘Colorado’ Rita Blue.

That’s a lot of stuff for any one person to manage, so I recommend getting one or more friends/colleagues in on the fun. That was the secret sauce for the Torreon Ellis’ Blue colony. It involved five of us, plus a helpful botanist.

* There is a small caveat. A recent email from Utah butterfly rearer Todd Stout created some doubt in my mind (oh no, not that again!), but he also illuminated a path forward. It goes like this: if plants belonging to Eriogonum B grow sparsely among a thick stand of Eriogonum A, a known host plant for a particular dotted-blue species, a female looking to place eggs on A may inadvertently place an egg or two on B. I was relieved to hear that because I had such an experience a few years ago with Blue Copper (Tharsalea heteronea) south of Angel Fire in Colfax County. A female was placing eggs in a stand of wild buckwheats that included Blue Copper’s typical host, Redroot Buckwheat (E. racemosum) intermixed with Antelope Sage (E. jamesii v. jamesii), which normally hosts Euphilotes centralis. While photographing the copper, I watched it stand on a Redroot Buckwheat plant and place an egg on an Antelope Sage inflorescence with which the redroot was entangled. I was not sure what to make of it at the time, but Todd has clarified that busy females can occasionally mis-place an egg.

Thus, Crispleaf Buckwheat can in some (I hope rare) circumstances also host Pallid Blue (Euphilotes pallescens) basically by accident. Thus, you might have crispleaf buckwheat and conclude you have Ellis’ Blue, and you probably do, BUT . . . per Todd . . . if the Crispleaf is merely an occasional plant among a dense stand of E. pallescens‘ normal host, E. leptocladon, then pallescens females may inadvertently place eggs on the Crispleaf, too. Larvae hatch, don’t know the difference, and do fine chewing the Crispleaf.

Todd’s passion for rearing every species from eggs gives him special knowledge and insights: last instar larvae of ellisi and pallescens are distinctively different. Tracking them down on the host plant is not particularly difficult. He says to visit the buckwheat patch about a month after peak adult flight (that would be mid-September in most of NM). Place a white cloth under some inflorescences, vigorously shake or knock (with a stick), until larvae fall onto the cloth, then obtain photos (or specimens). His graphic below shows how to differentiate ellisi larvae from pallescens larvae.

That situation does not necessarily apply to the Torreon site, but it is good practice for us observers to go back and check larvae – it’s an opportunity to gather another bit of evidence that can further seal the deal of dotted-blue identification. Moreover, it is easily done and what else are we going to do in mid-September? This task will have to wait until next year, but hey, we can do it! Just add that step to the formula.


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