Here is the NatureServe summary dump for the species - written about 20 years with updates relative to records (some aspects were reviewed in 2019). Sorry for the crappy formatting of the text transfer.
One thing worth noting is that this species and its hostplants are found in glade openings in forested settings. Glades are natural "prairie-like" openings in forest - and Missouri is aggressively restoring these habitat on State and Federal land across the Ozarks. Over decades of fire suppression, much of this open habitat type was lost. Oak woodlands became dense forests. Plus, CCC projects planted open habitats to pine in the 30's, which specifically targeted glades as unforested waste areas. Both State and feds are now using timber harvests to restore open oak woodland/glade habitat structure across 10s-of-thousands of acres. Then fire is uses once every few years (10-year intervals I've heard) to maintain the open structure. Ultimately, this should increase habitat for the species if it makes it through the current decline.
Classification Scientific Name: Papilio joanae J. Heitzman, 1973 Other Common Names: Joan's Swallowtail (EN) Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Papilionidae Genus: Papilio Scientific Name Reference: Pelham, J. P. 2008. A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature. The Journal of Research on the Lepidoptera. Volume 40. 658 pp. Revised 14 February, 2012. Concept Reference: Opler, P. A., and A. D. Warren. 2002. Butterflies of North America. 2. Scientific Names List for Butterfly Species of North America, north of Mexico. C.P. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado. 79 pp. Name Used in Concept Reference: Papilio joanae NatureServe Unique Identifier: ELEMENT_GLOBAL.2.107246 NatureServe Element Code: IILEP94020 Related ITIS Names: Papilio joanae J. Heitzman, 1973 (TSN 777697) Taxonomic Comments: Scott (1986) and a few others have considered this a synonym of P. polyxenes, but recent mitochondrial DNA work by Felix Sperling not only shows these are distinct species but that jonae is closer to P. machaon than to the sympatric P. polyxenes. Conservation Status NatureServe Status Global Status: G2? Global Status (Rounded): G2 Global Status Last Reviewed: 8/25/2019 Rank Method Used: Ranked by calculator Reasons: This species has a very restricted range and is known from few records. The extreme scarcity of records from 2010-2019 suggests that the species has declined. The difficulty in confirming identifications complicates status assessment. Threats are almost certain to increase within a few decades when gypsy moth becomes a widespread pest in the Ozarks, which will likely result in extensive spraying at least for a few years. National & State/Provincial Statuses Sort By Status United States: N3 Arkansas: S1?, Missouri: S1S2 Other Statuses U.S. Endangered Species Act: None Committee on the Status of Endangered Wildlife in Canada (COSEWIC): None NatureServe Global Conservation Status Factors Range Extent: 20,000-200,000 square km (about 8000-80,000 square miles) Range Extent Comments: Very limited global range; essentially confined to the Ozark Region of Missouri and rarely adjacent Arkansas. One isolated record in Kentucky is of unknown significance. Estimated Number of Element Occurrences: 6 - 20 Estimated Number of Element Occurrences Comments: This rare and difficult to identify species is known from a limited number of localities in Missouri and perhaps one or two in Arkansas (BAMONA 2019). Number of Occurrences with Good Viability/Integrity: Unknown Global Protection: Unknown whether any occurrences are appropriately protected and managed Global Protection Comments: Occurrences in parks, etc. are probably protected for now. However, these may be threatened in the near future by gypsy moth spraying. Degree of Threat: High - medium Threat Comments: Moderately threatened now but threat likely to increase greatly if gypsy moth spraying becomes widespread in Missouri. Gypsy moth will become a generalized problem, at least short term and likely long term, there in the early 21st century. Presumably recolonization will occur in small spray blocks, but large suppression or eradication projects using BTK (especially if sprayed more than once) or persistent (on foliage) chemical biocides could eliminate occurrences long term. There is growing evidence that swallowtail larvae are exceptionally sensitive to BTK and that, in contrast to most sensitive Lepidoptera, larvae may be killed by the residue more than a month after application. It is not certain, but likely, that this species will prove highly susceptible. There is very little chance the gypsy moth itself would have a great impact on this species, and any limited impact might even be positive if oak-kill were to create new openings. There seems to be no evidence that collecting has been a problem and little chance that limited collecting would be--and collecting will usually be required to confirm a new occurrence. However, it is possible that intensive collecting for sale or exchange, especially of adult females or larvae, could impact populations. Fire at any season would be likely to cause high to total mortality in the affected area. Occasional wildfires probably create or improve habitat but it is likely frequent rotational burning (return intervals less than 5-10 years) have a negative impact. Impact of logging needs investigation. Thinning in particular might improve habitat. Spraying herbicide or otherwise destroying the understory would definitely have a negative impact by destroying foodplant and nectar flowers--possibly for decades or longer. Loss and fragmentation of habitat and gypsy moth spraying are the major concerns. Increased predation by introduced hornets and wasps is a possible concern. The species may also be threatened by hybridization (S. Buback, pers. comm. 2019). Long-term Trend: Unknown Long-term Trend Comments: Discovered too recently to evaluate long term trend, although the species has declined somewhat due to habitat loss and more recently by hybridization. Short-term Trend: Decline of 30-90% Short-term Trend Comments: This species is very rarely recorded. Apparently there is only one publicly available record and one other from the period 2010-2019 (Dupuis and Sperling 2016, BAMONA 2019, S. Buback, pers. comm. 2019). The species was formerly more common, suggesting that the species has undergone a decline of some magnitude. The difficulty in confirming identifications complicates trend assessment. Environmental Specificity: Narrow. Specialist or community with key requirements common. Environmental Specificity Comments: A species of woodlands and forest; not a habitat generalist like some related species. Other NatureServe Conservation Status Information Inventory Needs: More precise information on current occurrences needed. Distribution National and State/Provincial Distribution: United States: AR, MO Endemism: endemic to a single nation Ecology and Life History Mobility and Migration Colonial Breeder: No Non-Migrant: Yes Locally Migrant: No Long Distance Migrant: No Mobility and Migration Comments: A large, presumably strong flying butterfly. Non-migratory but presumably very mobile within habitats. However, while they might go unrecognized, adults are apparently not seen out of habitat. Habitat Terrestrial Habitats: Forest - Hardwood, Woodland - Mixed, Savanna, Woodland - Conifer, Woodland - Hardwood Habitat Comments: Habitats are mostly cedar glades, various other openings and sparsely wooded areas within ozark dry forests. This species does not use highly disturbed, weedy or agricultural habitats such as favored by PAPILIO POLYXENES ASTERIAS. Phenology Immature Phenologies: Hibernates/aestivates Adult Phenologies: Diurnal Phenology Comments: First adults eclose from overwintered pupae in spring, i.e. April at least into May, and begin ovipositing in a few days. Eggs probably hatch in a week or two depending on temperature. Larval and pupal stage then probably take about seven weeks after which the second adult brood starts. Reports of adults from April to September (e.g. Opler, 1992) suggest a partial third brood and that larvae probably occur into October. It is not known if some first brood pupae overwinter. Also Dale Schweitzer observes that overwintered pupae of the related P. polyxenes eclose from late April into July in New Jersey creating overlap of first and second brood adults and P. joanae could be similarly staggered. It is also possible some pupae diapause through two or more winters. Food Immature Food Habits: Herbivore Adult Food Habits: Nectarivore Food Comments: Larvae feed on various plants in the carrot family including species of Thaspium, Taenidia, and Zizia. Adults take nectar from a variety of available flowers. Management Summary Stewardship Overview: No, or very limited, gypsy moth spraying with either BTK or chemicals. Use Gypcheck if available, let most outbreaks run their course otherwise. Probably seriously affected by frequent fires. Adults should recolonize afterwards but it probably takes several years for populations to fully recover. Frequent fires or spraying will probably cause a long term decline or at least overall reduced numbers even if recovery is apparent after individual episodes. Fires might improve overgrown habitat but are not recommended for now in good habitat. For now if fires must be used the interval between them should be as long as possible consistent with the goals of burning. Burning more often than once a decade is unlikely to benefit this species, or most specialized associated Lepidoptera, in most situations. Impacts of infrequent fires need investigation. Biological Research Needs: Better understanding of impacts of infrequent fires is needed. Information on population structure and size is needed at some of the better occurrences using mark-release-recapture methods. Population / Occurrence Delineation Minimum Criteria for an Occurrence: Location associated with a substantial tract of forest or woodland containing significant amounts of the larval foodplants where there is evidence of presence(or historical presence) with potential for continued presence or regular recurrence; minimally based on a diagnostic specimen or exceptionally a photograph verified by a genuine expert. Due to the potential for the extremely similar and common black swallowtail which will enter forests, especially in the spring, sight records from any source should never form the sole basis for any EO and photographs may not be verifiable with certainty. A specimen or two is strongly recommended. Mapping Guidance: While full and precise EO boundaries will often be poorly known, open habitats such as agricultural lands, suburbia and prairie can be excluded. In many cases boundaries will coincide with those of forest remnants. Separation Barriers: Unknown. However, it is suspected that this species does not move widely across almost any landscape features like many other swallowtails. So it is likely that treeless landscapes are barriers. Separation Distance for Unsuitable Habitat: 5 kilometers Separation Distance for Suitable Habitat: 10 kilometers Alternate Separation Procedure: If in the opinion of an expert who has spent a lot of field time in the area or on the basis of actual data it appears that no movement occurs between forest patches separated by open or developed landscapes then smaller distances down to the minimum of I kilometer may be used. Separation Justification: Other swallowtails commonly move hundreds of meters to a few kilometers and rarely tens to hundreds of kilometers. However, this species has apparently never been recognized any substantial distance out of habitat and has a very limited overall range implying it is not as dispersive as most relatives. With no real information, 5 km is simply arbitrarily chosen. This figure seems very reasonable within contiguous forest where some parts are unsuitable habitat due to lack of foodplant. However, it is really completely unknown how much or how far adults will move between forest patches.
It is unlikely any contiguous area of suitable forested habitat where this species occurs at all would be consistently unoccupied. However, when available habitat has been largely unchecked assume that observations 10 kilometers or more apart represent separate EOs, even with suitable intervening habitat, until additional field work demonstrates otherwise. This procedure is arbitrary and probably unrealistic since intervening suitable habitat should generally be occupied. Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 10 kilometers Inferred Minimum Extent Justification: Use this figure for contiguous expanses of forest with no distances of five kilometers or more between patches of foodplants. Date: 2001-04-18 Author: Dale Schweitzer Population / Occurrence Viability See the Generic Guidelines for the Application of Occurrence Ranks (2008). Authors and Contributors NatureServe Conservation Status Factors Edition Date: 8/25/2019 NatureServe Conservation Status Factors Edition Authors: Schweitzer, D.F., rev. B. Young (2019) References Brock, J. P., and K. Kaufman. 2003. Butterflies of North America. Kaufman Focus Field Guides, Houghton Mifflin Company, New York, NY 284 pp. Dupuis, J. R., and F. A. H. Sperling. 2016. Speciation, hybridization, and conservation quanderies: what are we protecting anyway? News of The Lepidopterists’ Society 58(4):202-204. Heitzman, J. R. 1974 ["1973"]. A new species of Papilio from the eastern United States (Papilionidae). Journal of Research on the Lepidoptera. 12(1):3-7. Heitzman, J. Richard and Joan E. Heitzman, 1987. Butterflies and Moths of Missouri. Missouri Dept. of Conservation, Jefferson City, MO. 385pp. Lotts, K. and T. Naberhaus, coordinators. 2019. Butterflies and Moths of North America (BAMONA). Bozeman, MT: Big Sky Institute. Online. Available: www.butterfliesandmoths.org/ Opler, P. A., and A. D. Warren. 2002. Butterflies of North America. 2. Scientific Names List for Butterfly Species of North America, north of Mexico. C.P. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado. 79 pp. Opler, P.A. and V. Malikul. 1992. Eastern Butterflies (Peterson Field Guide). Houghton Mifflin Company, Boston, Massachusetts. 396 pp. + color plates. Pelham, J. P. 2008. A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature. The Journal of Research on the Lepidoptera. Volume 40. 658 pp. Revised 14 February, 2012.