My guess is that butterflies are much, much easier to identify than plants. Less possibilities means an easier time.
I think a lot of us plant IDers are more shy about committing to an ID unless we know for sure. I’ve had way too many times that I IDed something local only to find out ‘oops, there’s a species I didn’t even realize existed, time to go fix my past sins’.
Please include the food plants with caterpillar finds! It helps us to know where to look.
I’ve seen a grand total of 1 pipevine swallowtail in Delaware. They are not that common here, though I know there are other sightings. It might have migrated in from PA because the state line is not far. I’ve never seen pipevine in DE, but then I could easily miss such a plant. (Once I’ve see a plant, I can usually find it elsewhere, but I’ve never glimpsed it.) We do have Canadian ginger, but I was reading a few sites that seem to indicate that people haven’t had much success rearing pipevine swallowtails on Canadian ginger. Still, I don’t know how true that is. Interesting question!
I’ve seen Endodeca serpentaria or whatever one wants to call it several times on the thickety parts of serpentine barrens, and once in northern Chesco with Janet Ebert. It’s kind of a dry woods and thickets sort of plant; I don’t usually see it flower, and, seconding @aspidoscelis, it just doesn’t jump out at you, especially when small, the way, say, a wild yam leaf would. If I were trying to run it to ground in northern Delaware, I’d probably scour the dry roadbanks down in Blackbird SF.
Thanks for the info! Maybe I’ll add it to my list of “things to find.” That list is getting kind of long at this point. :)
Not absolutely EVERYTHING in that family is a suitable host, but that’s a good point. There are other plants of the same family used as a host, not only the genus Aristolochia.
Thanks for all the responses so far!
At first I thought it was quite ridiculous that these plants would be so passed over… but now I’m not as shocked. Maybe they aren’t as keen to flower, deeper in the thickets, or higher up in the trees—these don’t stick to me as a plant that would stick out the way Mustang Grape does. And without the leaves, I can see how easy it might be to mistake one as something else, and how someone more familiar with ID-ing it for the flowers would pass over an observation of just the leaves.
Compared to how recognizable the Pipevine Swallowtail is, I can see how such a disparity could happen. Down in Texas though, with so many Pipevines observed, I’m sure there must be a much larger population of host plants supporting them… how many could we possibly be missing? I hope I can find one of them someday.
We have a similar situation in the San Francisco Bay Area with Gulf fritillaries: a wild butterfly dependent on cultivated host plants.
Not sure if those are actually host plants. Here’s another viewpoint on this: “Reports in the literature of larvae feeding on wild ginger, Asarum canadense L. (Aristolochiaceae), knotweed, Polygonum (Polygonaceae), and morning glories, Ipomoea (Convolvulaceae), are probably erroneous and likely due to misidentification of the host plant in the case of Asarum and to wandering larvae for the other plant species.” (source with references: https://entnemdept.ufl.edu/creatures/bfly/pipevine_swallowtail.htm)
They do love to wander around once they get big to find a place to pupate and spend the winter in their chrysalis. Both the butterfly and pipevine are quite common around here (mountains of North Carolina). I just checked our county and there’s 66 observations of the animal (48 butterflies, 13 caterpillars, 5 chrysalises) compared to just 18 of pipevine, none for Virginia snakeroot. I’ll have to keep an eye out for that one but it may not be as common in the mountains as it is in the Piedmont. Pipevine often escapes notion as it climbs up high into the trees, but once you know what to look for it’s pretty ubiquitous in our forests. The butterflies don’t stay there of course and are commonly seen in gardens around the area feeding on flowers that people have planted.
I have wondered the exact same thing here in Louisiana! I think Aristolochia serpentaria may be the host plant to watch for me. Now that I know what it is, I see it absolutely everywhere in my woods and it is very small and plain. I have never seen it in bloom. I am on a mission now to see if I can observe a bloom, caterpillar, or eggs on them.
Sorry, I forgot to add the source: Natural History Museum, London/UK
(https://www.nhm.ac.uk/)
Specifically https://www.nhm.ac.uk/our-science/data/hostplants/search/index.dsml - super useful website for caterpillar ID
Steve Cary, the NM butterfly expert, has this nice write-up for Pipevine Swallowtail in the state. Apparently the majority of records across the state are outside of areas with host plants so those individuals don’t reproduce.
https://peecnature.org/butterflies-of-new-mexico/swallowtails-papilionidae/#philenor
I’ve wondered about this question for years. I’m in SW Ohio where no pipevines are native and I still see these butterflies every year. Pipevine as a landscaping plant happens but rarely.
I’m not convinced that they’re reproducing much on serpentaria either. The larva eat a truly impressive amount of leaves, it would take several serpentaria plants just to feed a single caterpillar.
Also Asarum canadense isn’t a larval host I’m pretty sure. Some source documented that it was in the 1970s but there’s no evidence to back it up. There aren’t any photographs of the larva on this plant, no photos of oviposition, and nobody ever sees these plants defoliated. Anecdotally, in Facebook groups about butterflies, people have experimented putting the larva on A. canadense and observed that they leave the plants without feeding.
As Ann-etc pointed out, the one species of Pipevine (‘macrophylla’; Dutchman’s Pipe) is abundant in our North Carolina mountains. But I’m super guilty of noticing things like butterflies, making an iNat post about that butterfly, but forgetting all about the plants I also saw nearby. It’s bewildering to me. Part of my work involves doing vegetation surveys for birds I study - I know my plants. I don’t have time to upload to iNat all of those data. But I could do some for the plant-butterfly observations I make. I have worked in our mountains for many years, I’ve photographed ‘macrophylla’ but yet, I’ve never posted any to iNat. A bad oversight on my part. Imagine how many others do this?
Also, this same larger “tree-climbing” species, (again ‘macrophylla’ species), is now planted in nurseries around at least our Piedmont. Also, at least one formal (University) garden in our area has big clumps of a chinese species. The swallowtail larvae happily feed on it and pupate. I can’t say whether they hatch out and keep reproducing but they are very attracted to this asian variety.
And I myself am “guilty” as well. I have planted our two native species in my yard but really, the ‘macrophylla’ is not native here in Raleigh. Where I work (Natural Science Museum) we manage about 25 hectares of meadow, nearby. We have several large vine clumps of ‘macrophylla’ and they are always full of Swallowtail larvae and adults zipping around the property.
I know who wrote the NC report, for the females laying on Endodeca in our Piedmont region and completely trust that account. And he’s correct - it is the only true Piedmont native larval host. Still, I doubt that this is a very viable way of life for these swallowtails and their subsequent larvae. I agree that most of us walk past these plants and so perhaps there are clumps large enough to support a larvae or two out there. I have my doubts and feel that in NC, this Swallowtail is really a mountain species, with the usual pioneers striking out all the time. And now, finding “captive” Dutchman’s Pipe colonies in numerous places here.
As for who reports what: I do a lot of education and outdoor hikes. The people on my trips, who use iNaturalist, are not reporting plants, for the most part. Nor many arthropods. Many of them will only report what they know and what they know are vertebrates or the “marketed” things like Monarchs and milkweeds…
I want to second this quote:
I’ve led several butterfly counts and people are rarely interested in the plants. I believe that a lot of random observations of the butterfly come in as well from the fact that pipevine swallowtails are large, vivid insects and they will attract attention because they are photogenic. You don’t find a lot of incidental photos of brown skippers.
As for the comparison of milkweeds and Aristolochia spp, most milkweeds are obvious, especially when in flower and they can be identified in a field from a moving vehicle. That is not so for pipevines. I have one on my property and I would have to spend some time to (a) find one in the wild, and (b) identify it. I suspect that you could get milkweed IDs from google earth if the photos were taken in the right season.
the bulk of my pipevine observations come from my own garden, which has cultivated pipevine plants that I don’t put in (I do put in occasional volunteers that pop up that I don’t recognize, but not things I planted).
Couple that with the fact that plants generally are underreported, and that iNat seems to flag non-native plants as “captive/cultivated” very readily and I suspect that’s most of your answer
Here’s A california on Calflora (California): https://www.calflora.org/app/taxon?crn=674
They don’t have any other form but the native documented.
I’m working on building a bio corridor for Pipevine Swallowtail through Oakland from the Oakand and Berkeley Hills in order to increase populations in the Bay Area which . So handing out plants to interested people on NextDoor.
For those in the Bay Area, there is a big population out at Point Molate and Point San Pablo in Richmond. They’re coming out of the Oak forest on the hill in between the two, where there must be a plethora of plants.
Since they are cultivated, and iNat considers all those observations casual, I am sure less people add the,. For instance, I’ve had aristolochia litteratus in my yard for 19 years. I just had my first californicus plant bllom this week, but I haven’t put either on iNat since they’ll be casual without a butterfly on them. It’s one of my continued frustrations - not allowing cultivated plants to be verifiable observations. It really deflates the impetus to document a lot of urban habitat for wildlife.
