Speyeria idalia - (Drury, 1773)
Regal Fritillary
Other English Common Names: regal fritillary
Taxonomic Status: Accepted
Related ITIS Name(s): Speyeria idalia (Drury, 1773) (TSN 777993)
French Common Names: argynne majestueuse
Unique Identifier: ELEMENT_GLOBAL.2.114908
Element Code: IILEPJ6040
Informal Taxonomy: Animals, Invertebrates - Insects - Butterflies and Moths - Butterflies and Skippers
 
Kingdom Phylum Class Order Family Genus
Animalia Mandibulata Insecta Lepidoptera Nymphalidae Speyeria
Genus Size: C - Small genus (6-20 species)
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Concept Reference
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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.
Concept Reference Code: B02OPL01EHUS
Name Used in Concept Reference: Speyeria idalia
Taxonomic Comments: The recognition of eastern (mainly non-prairie wet meadows) and western prairie populations as separate subspecies (Williams, 2002) is tentatively accepted in this database. For now it is uncertain exactly which subspecies occurred in a few states and in Ontario.
Conservation Status
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NatureServe Status

Global Status: G3
Global Status Last Reviewed: 27Jan2008
Global Status Last Changed: 24Feb2000
Rounded Global Status: G3 - Vulnerable
Reasons: This species cannot be considered secure but it may be holding its own for now in parts of Kansas (Powell et al., 2007) and Missouri--notably two states where it occurs more in pastures rather than in fire managed preserves. There are well over 100 extant "populations" but some are not viable or transient and in the core of the range many should probably be treated as metapopulation occurrences. The rank also relects the very recent large scale decline and range contraction, the causes of which are somewhat uncertain, resulting in a recent (mostly since 1970) loss of approximately 40% of historic range, and on-going decline in some or possibly all other parts of its range. The decline in numbers and area of coccupancy is well over 99%. The species is imperiled or worse in at least Wisconsin, Illinois, Pennsylvania and Virginia and in parts of the Dakotas. It is probably extirpated in about 15 other states and Canada. It is likely the species is declining in Iowa (Schlicht and Orwig, 1998; Kelly and Debinski, 1999; Williams, 1999), which is often considered a global stronghold. While the Regal Fritillary is still extant in many prairie remnants it does appear to be excluded or threatened in some remnants by excessive prescribed burning and to be held at low numbers at many occurrences by rotational burning. Some habitats are unoccupied for no obvious reason. Strong metapopulations are probably few except probably in Kansas and Missouri where the observations in Powell et al. (2007) suggest substantial metapopulations in mostly small pastures, and perhaps also in Nebraska. While defining and ranking approrpiate metapopulation occurrences would be difficult in that context, a few of these clusters might be quite viable (i.e. EORANK=B) even if the indivudal colonies are not large in area of occupancy or population size , nearly all occurrences elsewhere for which there are any data seem likely to be in the C-D range, with several potentially restorable high C quality sites (see Kelly and Debinski, 1999 for some examples in Iowa, also Rowe Sanctuary, Nebraska may have B-Rank potential). No suspected A quality examples are known. Note the ranking criteria are now somewhat old and might not apply well where the species is not occurring on isolated managed prairies. There are almost certainly still well over 20 more or less viable occurrences but most occurrences are more marginal and often isolated and therefore vulnerable to long term loss from natural factors including drought, flood, and unnatural factors such as too much fire, biocides, and habitat fragmentation. There is no convincing evidence the species is stable anywhere, although westward it does not appear to be crashing as rapidly as happened eastward from about 1970-1991 and the species may be fairly stable and not really imperiled in a few counties in Kansas and Missouri. To whatever extent the decline in places like Iowa is due to management practices rather than inadequate habitat per se, it should still be to some substantial extent reversible.
Nation: United States
National Status: N3 (01Sep1998)
Nation: Canada
National Status: NHB,N1M (18Nov2016)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arkansas (S1), Colorado (S1), Connecticut (SX), Delaware (SX), District of Columbia (SX), Illinois (S2), Indiana (S1), Iowa (S2), Kansas (S4), Kentucky (SX), Maine (SX), Maryland (SH), Massachusetts (SH), Michigan (SH), Minnesota (S3), Missouri (S3), Nebraska (S3), New Hampshire (SX), New Jersey (SNR), New York (SH), North Carolina (SX), North Dakota (S2), Ohio (SH), Oklahoma (S1S2), Pennsylvania (S1), Rhode Island (SX), South Dakota (S3), Vermont (SX), Virginia (S1), West Virginia (SH), Wisconsin (S1), Wyoming (S3)
Canada Manitoba (SHB)

Other Statuses

IUCN Red List Category: NE - Not evaluated

NatureServe Global Conservation Status Factors

Range Extent: 200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Range Extent Comments: Historically much more than a million square miles, but much less than half that now and the two remnant occurrences of subspecies idalia are so isolated as to be meaningless now in terms of current range. The range extended from coastal New Brunswick (ca. 1900, see Brower, 1974) across southern Maine, southern New Hampshire and Vermont and the three southern New England states, southern New York, extreme southern Ontario (resident?), southern lower Michigan and northwest into Manitoba and eastern Montana; in the east south at least to the Ohio Valley and down the Appalachians to northern Georgia. The southern limits coincided quite well with a January mean isotherm of about 36 degrees Fahrenheit (two degrees Celsius) or lower (Schweitzer) and Scudder (1889) considered the northern limit to coincide with an annual isotherm of 45 degrees Fahrenheit (seven degrees Celsius).

Layberry et al. (1998) questioned its residency in Canada but at least temporary colonies have occurred there as recently as the 1980s and it was probably a pre-settlement resident in Ontario oak savannas and prairies. There is no evidence it was ever established on the coastal plain south of the immediate Philadelphia suburbs in New Jersey.

The regal fritillary ranged through much of the former tall grass prairie biome from near the Canadian border (about 49 degrees North) into Oklahoma (about 36 degrees North) and extends a bit to the west in moist areas. It was resident at least to slightly above 47 degrees North. Scott's (1986) map shows an area of transient occurrence over 100 kilometers wide in parts of Manitoba, Montana, Wyoming and Colorado. This interpretation is reasonable, but uncertain. Note the wide latitudinal range, from at least around 36 to 47 (or farther) North in the prairie region and more constricted low elevation range eastward. There has been a drastic loss of range since 1980, probably especially since 1987 (e.g. Schweitzer, 1993). The southwestern limit still is extreme eastern Colorado, Kansas and extreme northeastern Oklahoma but Royer (1988) says it has disappeared from western North Dakota while persisting in the eastern part. Regals are historic or extirpated in all six New England states; Canada (if ever really established), New York, New Jersey, Maryland, Delaware, probably West Virginia (but see Allen, 1997 regarding Monroe County), Ohio, probably Indiana, and Michigan. By the late 1990s, a large population in central Pennsylvania (still extant in 2006) and another in Virginia were the only actually located extant occurrences east of the Illinois-Indiana border region, although there was one apparently reliable observation in western North Carolina in 1994. It is possible that eastern occurrences resulted from land clearing soon after European settlement in the 1600s and 1700s, since east of about Indiana the species was overwhelmingly found in pastures, hay meadows and other unnatural situations in the 1800s and 1900s. Williams (1999) presented very preliminary data suggesting that eastern populations are much older and later (2002) provided more details and named the western prairie entity as a subspecies. Scudder's (1889) range map was remarkably accurate.

Area of Occupancy: 26-2,500 4-km2 grid cells
Area of Occupancy Comments: Formerly a landscape level species occupying millions of hectares of tall grass prairie, now mainly as a few hundred scattered remnant colonies or metapopulations with most occupying about 100 hectares or less. Some sites are probably not occupied in some years--for example after complete burns, but also potentially not after droughts, floods etc. or for no obvious reason.

Number of Occurrences: 81 - 300
Number of Occurrences Comments: There are a few hundred individual colonies of varying persistence and quality distributed rather widely through what is now the core range in Kansas, Missouri and Nebraska, over 70 in Kansas alone. There are possibly still over 20 in Minnesota and/or South Dakota. However it is not clear how many functional metapopulations or otherwise viable occurrences this really represents, but under 80 or over 300 both seem unlikely. Despite any remaining state ranks to the contrary, this species is extirpated or at least historic in and east of Indiana except for two colonies in Virginia and a large one in Pennsylvania. It is ranked S1 or S2 (in which case should be reviewed) in North Dakota, Wisconsin, Oklahoma, Illinois, Arkansas, Colorado and Iowa, generally S3 in what is now the core range and also Minnesota and South Dakota. Some S3 ranks would probably be S2 if based on potentially viable occurrence standards (e.g NatureServe EOSPECs) rather than total individual sites.

Population Size: 2500 - 1,000,000 individuals
Population Size Comments: Approximately 100-200 viable breeding or metapopulations (educated approximation) remain and many more individual colonies. Most of these at least northward seem to be less than 200 adults (e.g. see Kelly and Debinski, 1998 and references therein), although there are few mark-release-recapture (MRR) estimates. Powell et al. (2007) estimate around 12,000 in one season for northeastern Kansas--a significant part of a core range along the Missouri-Kansas border. Available data and observations including theirs suggest lower densities and/or abundances elsewhere. However their estimates are not based on MRR but on densities derived from transects. It seems likely though that their methods would underestimate, rather than over estimate, abundance, in part because unseen individuals (disproportionately females) are probably not effectively accounted for without MRR. This species probably has over 50,000 adults most years but could occasionally go lower if fluctuations tend to be synchronized along the Missouri-Kansas border--e.g. perhaps during droughts. The estimate here is based heavily on the Powell et al. (2007) article and assumes these were reasonably representative but allows for the possibility of crashes in the core range, such as are not unusual in Lepidoptera in general although long term observations a limited with this species.







Number of Occurrences with Good Viability/Integrity: Some to many (13-125)
Viability/Integrity Comments: There are probably roughly 100 occurrences that could be considered viable metapopulations, but these may be mostly concentrated along the Missouri-Kansas border where there numerous are apparent metapopulations mostly in small active pastures, which probably represent a modest number of B-rankable occurrences rather than many marginal (C-D) ones, and possibly a few worthy of A-rank. Most breeding populations elsewhere probably average approximately 100-200 individuals which should be marginally viable (EORANK=C) but there is considerable annual fluctuation and most populations on preserves are periodically reduced in prescribed burns. Isolated colonies are probably mostly vulnerable to loss in catastrophic events such as storms, droughts, floods, accidental or inappropriate fires. Number of individuals can fluctuate drastically from year to year in some parts of the range, although maybe not as much in the remaining range as in the historic range. All known eastern populations that were around 100-200 adults in the 1980s were extirpated by about 1991. Besides natural fluctuations prescribed burns kill most to all larvae in the treated area.

Overall Threat Impact: High
Overall Threat Impact Comments: Loss and fragmentation of habitat to agriculture (other than pasture or hayfield) and development, conversion of pastures and hay fields to plowed croplands, reforestation, pesticides, herbicides, and inappropriate and/or overuse of fire (usually prescribed burning) are among the known or reported threats. Factors such as those above are probably often the ultimate causes of decline via a break down of metapopulation function. This species is generally highly dependent on management, either on preserves (usually prescribed burning) or in active pastures which are probably its best habitats (Powell et al., 2007). Since this species is now reasonably common primarily near the southern limit of its range and generally fragmented elsewhere, global warming has to be included as a threat, since losses there would not be made up by expansion farther north where habitats are scarcer. Weather is often the final blow to a colony. Ann Swengel's work (1990, 1991, 1996, 1997, 1998) among other sources (such as Schlicht and Orwig, 1998) raises concern that prescribed burning practices, especially short return intervals (less than five years), could threaten some populations of regal fritillary, arogos skipper and other prairie specialists. Several credible instances of recent prescribed burning apparently eradicating populations of globally rare Lepidoptera are reported, e.g. Hesperia dacotae(G2G3) from its last Iowa site (Schlicht and Orwing, 1998), several Papaipema colonies in Michigan (see EMG for genus), Atrytone arogos arogos (G3T1T2) from its best known Florida occurrence (probably along with other globally rare skippers) and an extremely close call (which may yet prove to be an eradication) from its last known Carolina occurrence. Presumably most such eradications go unnoticed. While Swengel's data and analyses have been attacked as less than perfect (e.g. see Schwartz, 1998 and Swengel's accompanying rebuttal), her critics have not produced any contradictory data for regal fritillary. Panzer (1998) includes little on regal fritillary since it was already absent from most of his study areas. Swengel's (1996, 1997) results with regal fritillary do show numbers are lower on sites managed with rotational fire as opposed to those maintained by haying or grazing. Her analyses are based on very conservative nonparametric statistics applied to thousands of observations at a lot of sites in three different prairie regions (analyzed separately, but producing similar results). Heterogeneity of site conditions and conservative statistics should substantially obscure, not produce, significant relationships and yet many analyses are significant. There seems little doubt that regal fritillaries (and especially Atrytone arogos iowa) are depressed by rotational burning at the intervals used (typically at two to five years) at Swengel's study sites as opposed to haying or grazing. Schwartz's comments notwithstanding, numbers (or density) obviously are related to probability of persistence. Some other details like recovery time seem less clear (see Schwartz, 1998). Also unlike most prairie specialist Lepidoptera, regal fritillaries depend on cool season plants (violets) that tend to decrease with fire (Swengel, 1997 and references therein). Given the evidence for high (likely usually greater than 90 percent) direct mortality to larvae in burned units for this and other litter dwelling immatures (see also Panzer, 1998) complete burns at any frequency are a clear threat and probably explain some current absences (e.g. see some comments in Kelly and Debinski, 1999). One credible report of fire eradicating a major regal fritillary population is known and there are other suspected cases. David Parshall and John Shuey (pers. comm., separately, to D. Schweitzer, 1992) both reported that a single hot complete winter burn in the 1980s apparently eradicated regal fritillary from what is now Resthaven Wildlife Area in Ohio where a large (most of a section) prairie had for decades been an excellent place to find regal fritillary. Kelly and Debinski (1999) had to eliminate a potential regal fritillary study site due to burn impacts. Fire was probably not a large-scale factor in the decline of regal fritillary in the east (but see Bird, 1934). There is no field evidence implicating parasites or pathogens for declines, although the out of control (and largely ineffective) gypsy moth biocontrol Compsilura concinnata obviously must be considered in any sudden Lepidoptera crashes in the Northeast. Schweitzer believes it is unlikely to be a serious threat to regal fritillaries, since C. concinnata is mainly a forest species. There has not been a concurrent collapse of S. diana, S. atlantis, or S. cybele which are much more associated with wooded or edge habitats than S. idalia is. Overcollecting is a threat with small or concentrated occurrences, but was not a major factor in the overall decline. Extreme overcollecting apparently eradicated a population at Gunpowder State Park, Maryland (documentation in Maryland Heritage files). Over 50 adults were collected on 4 and 6 July 1978 and the population disappeared soon after that. There were rumors of a second incident of this type in Maryland in the 1980s. The main reason this species is vulnerable to overcollecting is that the early season females removed have not reproduced. Collecting has very seldom been a problem with butterflies in North America and Pyle et al. (1981) could find no credible instances of collectors causing even local extirpations. Drift or direct application from gypsy moth spraying is a clear threat and a BTK application is very strongly implicated for the sudden extirpation of the decades old population at Gettysburg National Park, Pennsylvania in the early 1980s. Speyeria larvae would be about second or third instar at spray time, and most Lepidoptera are very sensitive to BTK in the first two instars at least and S. diana is highly so in the third (Peacock et al., 1998). The decline of regal fritillary in some parts of the Northeast, such as northern New Jersey and parts of southern New England, did coincide with multi-million hectare DDT based gypsy moth control programs in the late 1950s and early 1960s. Mosquito adulticide spraying has not been reported or investigated as a problem with regal fritillary, although it potentially could be depending on concentration and type of biocides used. Schweitzer has observed repeatedly that Malathion at supposedly three ounces per acre applied in very early morning or early evening has little impact on most adult butterflies and possibly none on caterpillars, but higher doses or other biocides might annihilate populations, since nearly all of them affect a great variety of organisms (Jankowski, 1989). Royer and Marrone (1992) consider grasshopper spraying a threat throughout the Dakotas and this issue surfaced widely in Minnesota in 1990. They also cite herbiciding of foodplants and nectar plants as a widespread threat in the Dakotas along with invasion by exotic grasses. Iftner et al. (1992) cite herbicides as a problem in Ohio and Nagel (1992) mentions herbicides as a factor in Nebraska. Royer and Marrone (1992) also mention mowing of nectar flowers as a widespread problem. Others have also noted this as a more localized threat. Once populations of Regal Fritillary become reduced to one or a few discrete patches they become very vulnerable to single uncontrollable catastrophic events. For example all three surviving New England offshore island populations (in the range of about 100-200 adults each in the mid 1980s) were known to have been directly impacted by salt spray from Hurricanes Gloria in 1985 (Martha's Vineyard; less so Nantucket) or Bob in 1991 (Nantucket and Block Island) and all were extirpated (permanently) within one to three years. Various observations suggested the Nantucket population had already dropped to low levels before the second and more damaging hurricane and Mello (1989) shows that the Block Island one definitely did, perhaps due to recent cool, damp springs. At any rate the depleted remnant populations were unable to withstand the impacts from Hurricane Bob, which may well have also been the final blow on nearby Long Island. Small population size also leaves colonies very vulnerable to more or less stochastic events. For example, the precise explanation for the final extinction at Fair Hill, Maryland (ca. 1993) is unknown and probably unimportant. The population was already down to less than 20 adults in the 1991 brood (Schweitzer by MRR), so almost any negative impact could have eliminated it. Frequent local extinction appears to have long been a pattern with eastern colonies. Exotics plants such as brome grass have degraded or destroyed much prairie habitat westward and while alien weeds have never been suggested as a widespread impact to regals eastward (e.g. Schweitzer, 1989), they very well could have been involved in the decline. Unnatural eastern open habitats, especially those that have been previously plowed and farmed, are now often dominated overwhelmingly by a mixture of exotics early in the growing season when regal fritillary larvae are active. Quite possibly increases in cool season exotics reduced violets in some eastern regal fritillary habitats in the mid or late 20th century.

Short-term Trend: Decline of 30-70%
Short-term Trend Comments: Regal fritillary has declined severely in more than half of its range (Schweitzer, 1993; Williams, 1999), but is probably (not demonstrably) more or less holding its own in some prairie regions for now. Williams reports that the species becomes much scarcer east of about the Missouri River. The best assessment as of 1999 (based on many sources) is that eastern regal fritillaries crashed to near extinction from the 1960s-early 1990s; while prairie populations in Illinois and Wisconsin are threatened now (S1 or S2), and populations farther west vary locally from declining in Iowa (Kelly and Debinski, 1999; Schlicht and Orwig, 1998) to apparently (but not demonstrably) stable in some other states such as Missouri and Kansas. The best chances for survival now are in prairie remnants managed with minimal or no fire and on large remnants (greater than 65 hectare) managed with infrequent partial burns. Regal fritillary is, or should be, considered historic or extirpated in all of its former range east of the Indiana-Illinois border region except for single metapopulations known extant in Pennsylvania (likely EORANK=B) and Virginia (likely EORANK=C) (Schweitzer, 1992, Williams, 1999). Regals apparently died out in northern New England before 1950, mainland southern New England by 1960, except in New Haven and Litchfield Counties, Connecticut not until the 1970s. Extirpation in New Jersey and southeastern Pennsylvania occurred by the early 1970s and in Michigan soon after 1978. The account in Shapiro (1974) suggests the species was in decline or absent in most of New York by the early 1970s. Regal fritillary was extant in Ohio and West Virginia into at least the late 1980s. A tiny eastern Maryland-Pennsylvania border population persisted until about 1993. A metapopulation on Martha's Vineyard Island, off Massachusetts died out about 1987. Populations on Nantucket island, off Massachusetts, Block Island, off Rhode Island and eastern Long Island, New York persisted until about 1991. Extirpation may not have occurred yet in North Carolina, although despite substantial effort none have been seen there since 1994 and that was a single individual. There seems to have been a general northeast to southwest pattern of extirpations, with an obvious exception of longer persistence on off-shore islands. It should be noted than over 12,000,000 acres were sprayed with DDT for gypsy moth control from northern New Jersey to central New England in the late 1950s (mostly in May and June) with unknown acreage sprayed later in the season for mosquito control around that time and in the 1960s. Block Island and the Massachusetts Islands were apparently not extensively sprayed, but Long Island was. The most ominous trend for regal fritillary now may be the breakdown of metapopulation dynamics over most of the range (Kelly and Debinski, 1999; Royer and Marrone, 1992; Schweitzer, 1989). Since no single cause can seemingly explain the collapse of the regal fritillary in the east and many observers described it as rare, sporadic or tending to not persist, it seems very likely that some combination of increased local extinction rate and/or decreased colonization rate from about the late 1950s on led to the elimination of the species from almost all of the east (Schweitzer, 1989).

Long-term Trend: Decline of >90%
Long-term Trend Comments: This species has declined by about 99.9% based on habitat loss and range contraction alone. It is unlikely its current numbers approach 0.1% of orginal numbers in the prarie region and it is nearly extirpated east of there. A former landscape level species now reduced to scattered, sometimes isolated, remnant colonies. This species was probably about as characteristic of tall grass prairie as bison and far more abundant.

Intrinsic Vulnerability: Moderately vulnerable
Intrinsic Vulnerability Comments: This landscape level species has been reduced to remnant colonies in most places mostly of 100 or so adults or less, and is prone to year to year fluctuations, meaning small colonies may die out. In addition it is vulnerable to fire, drought, ill-timed mowing and probably other disturbances. It is on the other hand a mobile species and females do disperse and occasionally reach new sites

Environmental Specificity: Narrow. Specialist or community with key requirements common.
Environmental Specificity Comments: In most of its range restricted to prairie or savanna remnants, but eastward formerly found in a greater range of mostly unnatural habitats. This species is nowhere near as generalized as its foodplants and nectar sources.

Other NatureServe Conservation Status Information

Inventory Needs: Monitor status, especially in Illinois, Wisconsin, Iowa, and Pennsylvania. Determine status in Appalachian region. Note: some Lepidopterists now withold new site information from TNC and state DNRs out of concern that such sites will be reduced or lost with introduction of aggressive burning. Extent of this is unknown.

Protection Needs: Possibly sufficient number of protected occurrences in Midwest, but Swengel's work suggests changes in management as a need on many. For now protection of all occurrences capable of sustaining long term metapopulations in the Midwest and some attempt to protect or restore any extant possibly viable population in the east is recommended. Protection may not require strict preserve status, e.g. the species may do better in lightly to moderately grazed prairie or prairie hay meadows than in pristine fire managed preserves.

Obviously protection of both surviving occurrences east of the prairie region is the most critical immediate need, especially if on-going DNA and wing character studies (Williams, 1999) demonstrate differences between these and prairie populations based on meaningful sample sizes from several places. The preliminary report was too popularized to allow evaluation. His later description of thesubspecies occidentalis included more detail.

While most or all Midwestern sites still supporting regal fritillaries would be of conservation interest for their prairie flora, this would usually not be the case eastward. The extant Pennsylvania site is essentially unnatural and does not harbor many rare plants. It does have Leonard's skipper (HESPERIA L. LEONARDUS), another grassland/savanna species in severe decline in parts of the Northeast that co-occurred with regal fritillary on all recent New England islands sites and on many prairies. The Virginia occurrence is probably still an active hayfield. Thus protection could involve some sites that are not otherwise very appealing and which do not harbor high quality communities. They might have birds of interest such as grasshopper sparrow and upland sandpiper.

Distribution
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Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Historically much more than a million square miles, but much less than half that now and the two remnant occurrences of subspecies idalia are so isolated as to be meaningless now in terms of current range. The range extended from coastal New Brunswick (ca. 1900, see Brower, 1974) across southern Maine, southern New Hampshire and Vermont and the three southern New England states, southern New York, extreme southern Ontario (resident?), southern lower Michigan and northwest into Manitoba and eastern Montana; in the east south at least to the Ohio Valley and down the Appalachians to northern Georgia. The southern limits coincided quite well with a January mean isotherm of about 36 degrees Fahrenheit (two degrees Celsius) or lower (Schweitzer) and Scudder (1889) considered the northern limit to coincide with an annual isotherm of 45 degrees Fahrenheit (seven degrees Celsius).

Layberry et al. (1998) questioned its residency in Canada but at least temporary colonies have occurred there as recently as the 1980s and it was probably a pre-settlement resident in Ontario oak savannas and prairies. There is no evidence it was ever established on the coastal plain south of the immediate Philadelphia suburbs in New Jersey.

The regal fritillary ranged through much of the former tall grass prairie biome from near the Canadian border (about 49 degrees North) into Oklahoma (about 36 degrees North) and extends a bit to the west in moist areas. It was resident at least to slightly above 47 degrees North. Scott's (1986) map shows an area of transient occurrence over 100 kilometers wide in parts of Manitoba, Montana, Wyoming and Colorado. This interpretation is reasonable, but uncertain. Note the wide latitudinal range, from at least around 36 to 47 (or farther) North in the prairie region and more constricted low elevation range eastward. There has been a drastic loss of range since 1980, probably especially since 1987 (e.g. Schweitzer, 1993). The southwestern limit still is extreme eastern Colorado, Kansas and extreme northeastern Oklahoma but Royer (1988) says it has disappeared from western North Dakota while persisting in the eastern part. Regals are historic or extirpated in all six New England states; Canada (if ever really established), New York, New Jersey, Maryland, Delaware, probably West Virginia (but see Allen, 1997 regarding Monroe County), Ohio, probably Indiana, and Michigan. By the late 1990s, a large population in central Pennsylvania (still extant in 2006) and another in Virginia were the only actually located extant occurrences east of the Illinois-Indiana border region, although there was one apparently reliable observation in western North Carolina in 1994. It is possible that eastern occurrences resulted from land clearing soon after European settlement in the 1600s and 1700s, since east of about Indiana the species was overwhelmingly found in pastures, hay meadows and other unnatural situations in the 1800s and 1900s. Williams (1999) presented very preliminary data suggesting that eastern populations are much older and later (2002) provided more details and named the western prairie entity as a subspecies. Scudder's (1889) range map was remarkably accurate.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AR, CO, CTextirpated, DCextirpated, DEextirpated, IA, IL, IN, KS, KYextirpated, MA, MD, MEextirpated, MI, MN, MO, NCextirpated, ND, NE, NHextirpated, NJ, NY, OH, OK, PA, RIextirpated, SD, VA, VTextirpated, WI, WV, WY
Canada MB

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
CO Boulder (08013), Jefferson (08059), Kit Carson (08063), Larimer (08069)
CT Litchfield (09005)*
DE New Castle (10003)*
IA Adair (19001), Black Hawk (19013), Buena Vista (19021), Butler (19023), Calhoun (19025), Cass (19029), Cerro Gordo (19033), Cherokee (19035), Clarke (19039), Clay (19041), Clinton (19045), Dallas (19049), Dickinson (19059), Emmet (19063), Floyd (19067), Greene (19073), Guthrie (19077), Hancock (19081), Howard (19089), Iowa (19095), Jasper (19099), Kossuth (19109), Louisa (19115), Lyon (19119), Madison (19121), Mahaska (19123), Mills (19129), Monona (19133), O Brien (19141), Osceola (19143), Palo Alto (19147), Plymouth (19149), Pocahontas (19151), Polk (19153), Pottawattamie (19155), Scott (19163), Shelby (19165), Story (19169), Warren (19181), Webster (19187), Woodbury (19193), Wright (19197)
IL Bureau (17011), Carroll (17015), Cass (17017), Grundy (17063), Iroquois (17075), Jo Daviess (17085), Kankakee (17091), La Salle (17099)*, Lee (17103), Mason (17125), Mcdonough (17109)*, Menard (17129)*, Morgan (17137), Ogle (17141), Peoria (17143)*, Pike (17149)*, Scott (17171), Tazewell (17179), Whiteside (17195), Winnebago (17201)
IN Jasper (18073), Lagrange (18087)*, Lake (18089), Newton (18111), Steuben (18151)*, Tippecanoe (18157)*, Wabash (18169)*
KS Franklin (20059)
KY Bullitt (21029)*, Clark (21049)*, Hardin (21093)*, Jefferson (21111)*, Knox (21121)*, Laurel (21125)*, Nelson (21179)*, Oldham (21185)*, Shelby (21211)*, Spencer (21215)*, Whitley (21235)*
MA Barnstable (25001)*, Berkshire (25003)*, Dukes (25007)*, Essex (25009)*, Hampden (25013)*, Hampshire (25015)*, Middlesex (25017)*, Nantucket (25019)*, Norfolk (25021)*, Plymouth (25023)*, Suffolk (25025)*, Worcester (25027)*
MD Baltimore County (24005)*, Carroll (24013)*, Cecil (24015)*, Harford (24025)*, Howard (24027)*, Montgomery (24031)*, Washington (24043)*
MI Berrien (26021)*, Branch (26023)*, Calhoun (26025)*, Cass (26027)*, Jackson (26075)*, Kalamazoo (26077)*, Lenawee (26091)*, Livingston (26093)*, Montcalm (26117)*, Newaygo (26123)*, Oakland (26125)*, Shiawassee (26155)*, St. Joseph (26149)*, Washtenaw (26161)*, Wayne (26163)*
MN Anoka (27003)*, Benton (27009)*, Big Stone (27011), Blue Earth (27013), Brown (27015), Chippewa (27023), Chisago (27025)*, Clay (27027), Cottonwood (27033), Dakota (27037)*, Dodge (27039), Douglas (27041), Faribault (27043), Fillmore (27045), Freeborn (27047), Goodhue (27049), Grant (27051), Hennepin (27053)*, Houston (27055), Isanti (27059)*, Jackson (27063), Kandiyohi (27067), Lac Qui Parle (27073), Le Sueur (27079), Lincoln (27081), Lyon (27083), Mahnomen (27087)*, Martin (27091), Mcleod (27085), Meeker (27093), Mille Lacs (27095)*, Morrison (27097)*, Mower (27099), Murray (27101), Nicollet (27103), Nobles (27105), Norman (27107), Olmsted (27109), Otter Tail (27111), Pipestone (27117), Polk (27119), Pope (27121), Ramsey (27123)*, Redwood (27127), Renville (27129), Rice (27131)*, Rock (27133), Scott (27139)*, Sherburne (27141)*, Sibley (27143)*, Stearns (27145), Stevens (27149), Swift (27151), Todd (27153), Traverse (27155), Wabasha (27157), Washington (27163)*, Watonwan (27165), Wilkin (27167), Winona (27169), Yellow Medicine (27173)
MO Adair (29001), Andrew (29003)*, Atchison (29005), Audrain (29007)*, Barry (29009)*, Barton (29011), Bates (29013), Benton (29015), Boone (29019)*, Buchanan (29021)*, Caldwell (29025)*, Callaway (29027)*, Cass (29037), Cedar (29039), Clay (29047)*, Clinton (29049), Cole (29051)*, Dade (29057), Daviess (29061)*, Gentry (29075), Harrison (29081), Henry (29083), Hickory (29085), Holt (29087), Jasper (29097), Johnson (29101)*, Knox (29103), Lafayette (29107)*, Lawrence (29109), Lewis (29111), Linn (29115)*, Macon (29121), Newton (29145), Nodaway (29147), Pettis (29159), Pike (29163)*, Polk (29167), Ralls (29173)*, Randolph (29175)*, Shelby (29205)*, St. Clair (29185), Sullivan (29211), Vernon (29217), Worth (29227)
NC Alleghany (37005)*, Ashe (37009)*, Avery (37011)*
ND Burleigh (38015), Cass (38017), Dickey (38021), Logan (38047), Ransom (38073), Richland (38077), Sargent (38081), Sioux (38085)
NE Blaine (31009), Boone (31011), Boyd (31015), Buffalo (31019), Chase (31029), Greeley (31077), Hall (31079), Howard (31093), Keya Paha (31103), Knox (31107), Merrick (31121), Nance (31125), Nemaha (31127), Pawnee (31133), Pierce (31139), Platte (31141), Sherman (31163), Sioux (31165), Stanton (31167)
NJ Bergen (34003)*, Cumberland (34011)*, Essex (34013)*, Middlesex (34023)*, Monmouth (34025)*, Morris (34027)*, Somerset (34035)*, Sussex (34037)*, Union (34039)*, Warren (34041)*
NY Cattaraugus (36009)*, Suffolk (36103)*
OK Osage (40113)
PA Adams (42001)*, Allegheny (42003), Beaver (42007)*, Bucks (42017)*, Butler (42019)*, Centre (42027)*, Chester (42029)*, Clearfield (42033)*, Cumberland (42041)*, Dauphin (42043)*, Delaware (42045)*, Greene (42059), Huntingdon (42061)*, Lancaster (42071)*, Lebanon (42075), Monroe (42089)*, Montgomery (42091)*, Philadelphia (42101)*, Westmoreland (42129)*, York (42133)*
RI Washington (44009)*
SD Bon Homme (46009), Brookings (46011), Brown (46013), Brule (46015)*, Campbell (46021), Charles Mix (46023), Clay (46027), Codington (46029), Corson (46031), Custer (46033), Day (46037), Deuel (46039), Dewey (46041), Douglas (46043), Edmunds (46045), Faulk (46049), Grant (46051), Gregory (46053)*, Haakon (46055), Hamlin (46057), Hughes (46065), Hutchinson (46067), Hyde (46069), Jerauld (46073), Jones (46075), Kingsbury (46077), Lawrence (46081), Lincoln (46083), Lyman (46085), Marshall (46091), McPherson (46089), Meade (46093), Minnehaha (46099), Moody (46101), Pennington (46103), Perkins (46105), Potter (46107), Roberts (46109), Shannon (46113), Stanley (46117), Sully (46119), Tripp (46123), Union (46127), Walworth (46129), Yankton (46135), Ziebach (46137)
VA Albemarle (51003)*, Amherst (51009)*, Augusta (51015)*, Bedford (51019)*, Craig (51045)*, Fairfax (51059)*, Fauquier (51061)*, Frederick (51069)*, Giles (51071)*, Grayson (51077), Highland (51091)*, Lee (51105)*, Loudoun (51107), Madison (51113)*, Montgomery (51121)*, Nelson (51125)*, Orange (51137), Page (51139), Pulaski (51155)*, Rappahannock (51157)*, Rockbridge (51163)*, Smyth (51173)*, Washington (51191)*, Wythe (51197)*
WI Chippewa (55017)*, Columbia (55021), Crawford (55023), Dane (55025), Green (55045), Iowa (55049), Jackson (55053), Juneau (55057)*, Monroe (55081), Ozaukee (55089)*, Portage (55097), Sauk (55111), St. Croix (55109)*, Trempealeau (55121)
WV Lewis (54041)*, Marion (54049)*, Mason (54053)*, Mineral (54057)*, Monongalia (54061)*, Monroe (54063)*, Preston (54077)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Middle Connecticut (01080201)+*, Charles (01090001)+*, Cape Cod (01090002)+*, Pawcatuck-Wood (01090005)+*, Housatonic (01100005)+*
02 Rondout (02020007)+*, Lower Hudson (02030101)+*, Hackensack-Passaic (02030103)+*, Sandy Hook-Staten Island (02030104)+*, Raritan (02030105)+*, Southern Long Island (02030202)+*, Middle Delaware-Mongaup-Brodhead (02040104)+*, Middle Delaware-Musconetcong (02040105)+*, Lehigh (02040106)+*, Crosswicks-Neshaminy (02040201)+*, Lower Delaware (02040202)+*, Schuylkill (02040203)+*, Delaware Bay (02040204)+*, Brandywine-Christina (02040205)+*, Cohansey-Maurice (02040206)+*, Upper West Branch Susquehanna (02050201)+*, Bald Eagle (02050204)+*, Upper Juniata (02050302)+*, Lower Susquehanna-Swatara (02050305)+, Lower Susquehanna (02050306)+*, Chester-Sassafras (02060002)+*, Gunpowder-Patapsco (02060003)+*, Patuxent (02060006)+*, South Branch Potomac (02070001)+*, North Branch Potomac (02070002)+*, Conococheague-Opequon (02070004)+*, South Fork Shenandoah (02070005)+, Middle Potomac-Catoctin (02070008)+, Monocacy (02070009)+*, Rapidan-Upper Rappahannock (02080103)+*, Pamunkey (02080106)+, Upper James (02080201)+*, Maury (02080202)+*, Middle James-Buffalo (02080203)+*, Rivanna (02080204)+*
04 Little Calumet-Galien (04040001)+*, Milwaukee (04040003)+*, St. Joseph (04050001)+*, Kalamazoo (04050003)+*, Upper Grand (04050004)+*, Lower Grand (04050006)+*, Muskegon (04060102)+*, Clinton (04090003)+*, Huron (04090005)+*, Ottawa-Stony (04100001)+*, Raisin (04100002)+*, Tiffin (04100006)+*
05 Upper Allegheny (05010001)+*, Lower Allegheny (05010009)+*, West Fork (05020002)+*, Upper Monongahela (05020003)+, Cheat (05020004)+*, Lower Monongahela (05020005)+, Youghiogheny (05020006)+*, Upper Ohio (05030101)+*, Connoquenessing (05030105)+*, Upper Ohio-Shade (05030202)+*, Upper New (05050001)+, Middle New (05050002)+*, Greenbrier (05050003)+*, Lower Kanawha (05050008)+*, Raccoon-Symmes (05090101)+*, South Fork Licking (05100102)+*, Lower Kentucky (05100205)+*, Eel (05120104)+*, Middle Wabash-Little Vermilion (05120108)+*, Upper Cumberland (05130101)+*, Silver-Little Kentucky (05140101)+*, Salt (05140102)+*, Rolling Fork (05140103)+*, Blue-Sinking (05140104)+*
06 North Fork Holston (06010101)+*, South Fork Holston (06010102)+*, Nolichucky (06010108)+*, Powell (06010206)+*
07 Redeye (07010107)+*, Long Prairie (07010108)+, Platte-Spunk (07010201)+*, Sauk (07010202)+, Clearwater-Elk (07010203)+*, Crow (07010204)+, South Fork Crow (07010205)+, Twin Cities (07010206)+*, Rum (07010207)+*, Upper Minnesota (07020001)+, Pomme De Terre (07020002)+, Lac Qui Parle (07020003)+, Hawk-Yellow Medicine (07020004)+, Chippewa (07020005)+, Redwood (07020006)+, Middle Minnesota (07020007)+, Cottonwood (07020008)+, Blue Earth (07020009)+, Watonwan (07020010)+, Le Sueur (07020011)+*, Lower Minnesota (07020012)+*, Lower St. Croix (07030005)+*, Rush-Vermillion (07040001)+*, Cannon (07040002)+, Buffalo-Whitewater (07040003)+, Zumbro (07040004)+, Trempealeau (07040005)+, La Crosse-Pine (07040006)+, Black (07040007)+, Root (07040008)+, Lower Chippewa (07050005)+*, Coon-Yellow (07060001)+, Upper Iowa (07060002)+, Apple-Plum (07060005)+, Castle Rock (07070003)+, Baraboo (07070004)+, Lower Wisconsin (07070005)+, Kickapoo (07070006)+, Copperas-Duck (07080101)+, Lower Wapsipinicon (07080103)+, South Skunk (07080105)+, North Skunk (07080106)+, Upper Cedar (07080201)+, Shell Rock (07080202)+, Winnebago (07080203)+, West Fork Cedar (07080204)+, Middle Cedar (07080205)+, Upper Iowa (07080207)+, Lower Iowa (07080209)+, Crawfish (07090002)+*, Pecatonica (07090003)+, Sugar (07090004)+, Lower Rock (07090005)+, Green (07090007)+, Des Moines Headwaters (07100001)+, Upper Des Moines (07100002)+, East Fork Des Moines (07100003)+, Middle Des Moines (07100004)+, Boone (07100005)+, North Raccoon (07100006)+, South Raccoon (07100007)+, Lake Red Rock (07100008)+, Bear-Wyaconda (07110001)+, North Fabius (07110002)+, South Fabius (07110003)+, The Sny (07110004)+*, North Fork Salt (07110005)+, South Fork Salt (07110006)+*, Salt (07110007)+*, Cuivre (07110008)+*, Kankakee (07120001)+, Iroquois (07120002)+, Chicago (07120003)+, Upper Illinois (07120005)+, Lower Illinois-Senachwine Lake (07130001)+, Lower Illinois-Lake Chautauqua (07130003)+, Lower Sangamon (07130008)+*, La Moine (07130010)+*, Lower Illinois (07130011)+
09 Bois De Sioux (09020101)+, Mustinka (09020102)+, Otter Tail (09020103)+, Upper Red (09020104)+, Western Wild Rice (09020105)+, Buffalo (09020106)+, Eastern Wild Rice (09020108)+, Lower Sheyenne (09020204)+, Maple (09020205)+, Red Lake (09020303)+
10 Middle Cheyenne-Spring (10120109)+, Middle Cheyenne-Elk (10120111)+, Lower Cheyenne (10120112)+, Lower Belle Fourche (10120202)+, Upper Lake Oahe (10130102)+, Apple (10130103)+, Beaver (10130104)+, Lower Lake Oahe (10130105)+, West Missouri Coteau (10130106)+, North Fork Grand (10130301)+, South Fork Grand (10130302)+, Grand (10130303)+, Fort Randall Reservoir (10140101)+, Bad (10140102)+, Medicine (10140104)+, Middle White (10140202)+, Lower White (10140204)+*, Niobrara Headwaters (10150002)+, Middle Niobrara (10150004)+, Keya Paha (10150006)+, Lower Niobrara (10150007)+, Upper James (10160003)+, Elm (10160004)+, Mud (10160005)+, Middle James (10160006)+, East Missouri Coteau (10160007)+, Snake (10160008)+, Turtle (10160009)+, Lower James (10160011)+, Lewis and Clark Lake (10170101)+, Vermillion (10170102)+, Middle Big Sioux Coteau (10170201)+, Upper Big Sioux (10170202)+, Lower Big Sioux (10170203)+, Rock (10170204)+, St. Vrain (10190005)+, Cache La Poudre (10190007)+, Middle Platte-Buffalo (10200101)+, Wood (10200102)+, Middle Platte-Prairie (10200103)+, Upper Middle Loup (10210001)+, Lower Middle Loup (10210003)+, Lower North Loup (10210007)+, Loup (10210009)+, North Fork Elkhorn (10220002)+, Lower Elkhorn (10220003)+, Blackbird-Soldier (10230001)+, Little Sioux (10230003)+, Monona-Harrison Ditch (10230004)+, Maple (10230005)+, Big Papillion-Mosquito (10230006)+, West Nishnabotna (10240002)+, East Nishnabotna (10240003)+, Tarkio-Wolf (10240005)+, South Fork Big Nemaha (10240007)+, Big Nemaha (10240008)+, West Nodaway (10240009)+, Nodaway (10240010)+, Independence-Sugar (10240011)+*, Platte (10240012)+, One Hundred and Two (10240013)+*, South Fork Republican (10250003)+, Frenchman (10250005)+, Upper Grand (10280101)+, Thompson (10280102)+, Lower Grand (10280103)+, Lower Chariton (10280202)+, Little Chariton (10280203)+, Upper Marais Des Cygnes (10290101)+, Lower Marais Des Cygnes (10290102)+, Little Osage (10290103)+, Marmaton (10290104)+, Harry S. Missouri (10290105)+, Sac (10290106)+, Pomme De Terre (10290107)+, South Grand (10290108)+, Lake of the Ozarks (10290109)+, Lower Missouri-Crooked (10300101)+*, Lower Missouri-Moreau (10300102)+*, Lamine (10300103)+, Blackwater (10300104)+*
11 Beaver Reservoir (11010001)+*, Caney (11070106)+, Bird (11070107)+, Spring (11070207)+
CA CAPE COD (CAPE COD)+*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: Regal fritillary, Nymphalidae.
General Description: See any butterfly book for eastern or central North America. Adult large, size of a Monarch. Upper side with reddish-orange forewings and velvety blackish hindwings with blue irridescence with two rows of spots on hindwing, both cream coloerd in female, outer row orangish in male. Underside forewing similar to upperside, but hindwing dark slightly greenish brown with many elongate whitish spots, no pale subterminal band.
Diagnostic Characteristics: No butterfly anywhere in the world resembles this one. Hindwings above absolutely unique. Because of size, females could be mistaken for a Monarch at great distances.
Reproduction Comments: Females lay several hundred up to 1000 eggs (Thomas Allen) apparently singly. They are placed near (usually within a few cm), but seldom on, violets. Eggs are attached, but the substrate varies from underside of pebbles to dead leaves. it does not seem to matter whether the violets have senesced or are vigorous. At least to most observers oviposition seems somewhat haphazard, but given that larvae seek a hibernation site quickly after hatching, Schweitzer suspects females may cue on factors other than foodplant in selecting the exact site. Based on observations of captive larvae, it appears they prefer to enter rolled over dried grass stems on the ground. While females are apparently in reproductive diapause and may remain rather inactive they do not go completely dormant, but do fly some and take nectar during this period. Reproductive diapause is probably more prolonged in southern parts of the range. Males are apparently ready to mate soon after eclosion and females are known to mate promptly, occasionally while still teneral (Barbara Barton).
Ecology Comments: May be unable to persist long term as isolated colonies due to frequent large fluctuations in numbers. Apparently densities of adults seldom reach 5 per acre over any large area. Normal population structure was metapopulations composed of often short lived demes with frequent recolonization. Serious concern about break down of metapopulation dynamics rangewide since most colonies are now isolated on preserves, which are often too small and sometimes inappropriately managed for Lepidoptera for this species. Metapopulation collapse seems to have been the cause of the massive recent decline eastward, that is colonization could not keep up with local extirpation rates.
Habitat Type: Terrestrial
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Adults usually stay in natal area, at least for several weeks, but some disperse for miles, and many females may eventually do so.
Palustrine Habitat(s): Bog/fen, HERBACEOUS WETLAND, Riparian
Terrestrial Habitat(s): Grassland/herbaceous, Old field, Savanna
Habitat Comments: Habitats were open grassy situations, ranging from xeric to quite hydric, completely flat to hilly. Subspecies S. i. occidentalis is almost entirely a tall grass prairie and prairie pasture specialist using dry, mesic and wet situations regularly. It may do best on xeric to mesic prairie associated with some wetter portions. It does not generally colonize non-prairie habitats such as were used by S. idalia idalia, which was found mostly in anthropogenic habitats such as wet meadows, pastures, hayfields, old fields, along streams in open areas; but it was using prairie-like xeric grassland habitats on east coast islands south to Long Island, New York and perhaps on mainland Cape Cod. Williams' (2002) statement (citing Scudder, 1889 and Opler and Krizek, 1984) that subspecies idalia was "typically found in xeric habitats" is inaccurate for most former populations. Actually Opler and Krizek stated that "damp meadows or pastures with boggy or marshy areas are frequently utilized...but dry mountain pastures are also selected in some areas" and Scudder also described a variety of habitats. Most other eastern references (e.g., Allen, 1997; Iftner et al., 1993; Klots, 1951, Shapiro, 1974) associate the species with moist, wetland, or streamside habitats and do not mention xeric habitats. Treed habitats seem to be effective barriers to adults, but species can occur in savanna if trees are sparse or clumped. Absence of this species in prairie preserves is a significant negative indicator for community integrity and probably sometimes reflects failure to have recovered from past management practices such as complete burns and/or small patch size. Studies by Ann Swengel in Wisconsin and Missouri indicate that this species is negatively impacted by prescribed burning at normal frequencies. Other observers have suggested the same. High densities at some unburned Missouri sites and an apparent substantial increase in Pennsylvania after cessation of burning support her views. Schweitzer suspects, based mostly on eastern habitats and direct observations of adults in Rhode Island, that subspecies idalia preferred recently or currently grazed areas and many references to it mention pastures. While more data are needed, it appears that there is a major difference between eastern and western subspecies in their ability to utilize artificial habitats such as hayfields and non-prairie pastures. This species may require relatively large habitats on the order of perhaps 50 hectares for a marginally viable occurrence.
Adult Food Habits: Nectarivore
Immature Food Habits: Herbivore
Food Comments: Populations require a large number of violet plants which are the sole larval foodplants. While Viola pedata and pedatifida are the usual foodplants of prairie subspecies occidentalis, these species were seldom present in eastern habitats and are not always the foodplants even westward. Probably essentially any species of violet that is prevalent in the habitats used. Contrary to Williams' (2002) suggestion there is virtually no evidence the eastern subspecies has different foodplant preferences from prairie populations. The Block Island, Rhode Island population used overwhelmingly V. fimbriatula and Williams is correct that this same species is the primary foodplant of the extant central Pennsylvania population. In both habitats virtually no other violets occur. Populations on the Massachusetts islands used at least Viola pedata and V. lanceolata sometimes within a few tens of meters of each other. Some, if not most, eastern habitats lacked all three of these violet species. Several other violets, perhaps most often V. papilionacea, were prominent in eastern pasture occurrences and that species is readily accepted by the larvae. Adults require a reliable source of nectar throughout their long flight season and will emigrate from an area quickly if this supply fails, either naturally as with Clethra on Nantucket in Schweitzer's observations or due to mowing. Except that red clover is not mentioned as a nectar plant in any of Swengel's observations but was among the three most important on Martha's Vineyard in the early 1980s, there does not seem to be much regional difference in nectar preferances, and most flowers used by butterflies generally are visited. Some major nectar plants include various milkweeds, perhaps especially Asclepias syriaca and tuberosa, thistles, Liatris, Echinacea, purple Eupatorium spp., ironweeds, Decodon, and probably less favored but important late in the season, Aster and Solidago species. Shrubs are not often reported but Clethra alnifolia was a major nectar plant on Nantucket. Schweitzer's impression is that Liatris and Asclepias spp. and especially A. tuberosa are used overwhelmingly when available, at least eastward. Many other flowers are used (Swengel, 1990, 1991). No single nectar genus is crucial and nectar resources nearly always change over the lifetime of at least females.
Adult Phenology: Diurnal
Immature Phenology: Diurnal, Hibernates/aestivates
Phenology Comments: Adult emergence typically starts in June, but may start as early as late May in warmest parts of range such as southeastern Pennsylvania, Virginia and Oklahoma. Emergence did not start until late July on the Massachusetts islands. Females emerge about a week or two weeks later than males, mainly in July, due to a longer larval period. Females usually do not oviposit until at least three weeks after eclosion and mating. Males apparently commonly live a month, female probably closer to two months. Eggs laid in August or September hatch in about 3-4 weeks. Larva occur approximately September or October to June or July. Hatchling larvae overwinter unfed, and become active in spring, apparently generally in April, as in all Speyeria. The pupal period is brief, apparently three weeks or less. Ignore longevity estimates (and population estimates) in Nagel et al. (1991) paper, which are incorrectly calculated and based on inadequate data (pointed out by L.F. Gall). Although larvae of this genus are widely claimed to be nocturnal all activity documented by Kopper et al.(2001) for this species was in the daytime.
Economic Attributes
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Economic Comments: Of no known economic importance.
Management Summary
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Stewardship Overview: The first need is to determine whether the species is present. Local Lepidopterists or butterfly watchers may already know or managers can determine this themselves in a few minutes to hours of appropriate effort. While most northern prairies probably have been checked for this species, all prairie managers from northeastern Oklahoma into extreme southern Manitoba should determine whether this species is present. This is extremely simple and the window of opportunity is at least about two months per summer but best early in the season (see Swengel, 1991, 1992, 1996 and Nagel et al., 1999 for details). Identification difficulty is comparable to robin or bluebird and can easily be done through binoculars and usually naked eye. Photo documentation without specimens is seldom a good idea with butterflies, but regal fritillary is an exception. Collection of a voucher is not necessary but not usually inappropriate.

Where an existing population has been maintained without fire, do not introduce fire. However, continued partial burning should not be precluded from consideration where fires have long been implemented except that a less destructive management tool should be considered for populations that commonly fall below 100 adults per season and is needed if populations smaller than about 50 adults most years are to have much of a chance. However Swengel (1996) advocates consistency of management.

In pasture situations, including prairie pastures, do not rush to curtail grazing. More data are clearly needed, but light to moderate grazing may be highly favorable to regals or their foodplant and are more favorable than burning (Swengel, 1996, 1997). Schweitzer found on Block Island, Rhode Island that ovipositing females did not avoid, and may have favored, currently grazed areas and those grazed by cattle within the previous month. The cattle conspicuously failed to severely graze the violets (V. fimbriatula) while removing most of the overstory. Mello (1989) found violets there to be much more common in grazed areas.

In agricultural regions there must be adequate buffer to dilute pesticide drift, including BTK before July, to innocuous levels. In regions such as the Dakotas and Minnesota where grasshopper outbreaks have resulted (e.g. in 1990) in state-mandated biocide spraying over large areas including potentially preserves where regal fritillary and state or globally rare species are likely to be affected, a response needs to be worked out in advance. In general grasshopper outbreaks are not a severe problem of native landscapes but there may be pressure to apply biocides to preserves anyway during outbreak years. In general, the response should be to preclude any such spraying by whatever means are appropriate. It may be useful to consult an attorney. As a last resort, if spraying cannot be prevented try to have a biocide used that is not persistent and likely to have the least overall impact. Malathion at three ounces per acre or less should be much less devastating to Lepidoptera and many other insects than some other biocides aimed at grasshoppers. Biocides other than Dimilin (Diflubenzuron) should usually not kill eggs, but larvae and adults would be at risk from almost all others except that only feeding Lepidoptera larvae are at risk from BTK or genetically engineered corn pollen containing BTK toxins. Dimilin might affect any stage by contact including fecundity of adult females.

As currently practiced, gypsy moth suppression spraying is normally carefully targeted. A regal fritillary occurrence would be unlikely to be deliberately targeted since gypsy moths are not a problem on prairies. In at least most states landowners can request to be deleted from a proposed spray block. In most cases BTK will probably be proposed. Be sure to request use of at minimum the currently accepted standard buffer where a spray block abuts a regal fritillary occurrence. At least in most places where local decision-makers have experience in dealing with gypsy moths, such requests are usually routinely honored and this should suffice to minimize impacts assuming recommended guidelines concerning wind and other factors are adhered to. It would be prudent to suspend prescribed burning for a year or two if the population appears depressed that season or if it is known (e.g. by monitoring spray cards) that some BTK drift did get into the habitat. For even greater safety, request that Gypchek (a virus lethal to little else besides gypsy moth larvae) be used instead. Such a request may be honored, depending in part on the availability of and demand for the product nationally that year.

Possibly an important long term stewardship need will prove to be restoration or maintenance of viable metapopulation dynamics or establishing translocation criteria (see Schweitzer, 1994) where doing this with natural dispersal is impossible.

An effort should be made to maintain any occurrence within the C element occurrence ranking specifications or better. If this is clearly impossible, the occurrence may not be salvageable but is possibly useful as an occasional "stepping stone" in local metapopulation dynamics. As was obviously the case repeatedly eastward, even apparently C ranked occurrences may prove unsalvageable.

Restoration Potential: Where populations still exist within the prairie region, restoration potential varies according to remnant size and what is depressing the population. Increasing violets should generally increase regals (Swengel, 1997; Kelly and Debinski, 1999). Less often nectar could be limiting especially in uniformly xeric sites. Swengel's (1996, 1997, 1998) work strongly suggests that changing from rotational burning to another management tool should usually increase numbers substantially and benefit other prarie specialists. If this is not an option increasing the number of burn units (especially if less than four currently) and number of rest years between fires should increase numbers. Likewise, it appears from Barton's work that the Pennsylvania population increased quickly when almost annual partial burning of its habitat ceased.

In the case of unoccupied habitats in the prairie region west of Illinois and Wisconsin, recolonization potential should be good if active colonies are close by (best guess two to four kilometers) without barriers such as woods and if management practices would permit a new population to build up to sustainable levels. It is not possible to quantify recolonization potential but in most settings dispersal does occur although certainly much of it is suicidal on today's landscapes. A successful recolonization will probably require several females to reach the site, ideally in the same season.

In places like the Chicago area prairies where most habitats are now vacant and highly isolated, few are over 100 hectares, and many have aggressive fire regimens (Panzer, 1998), natural recovery potential appears very poor and it is not obvious that management changes would improve the situation. On the other hand in places like the Iowa Loess Hills where many to most habitats are or ecently were occupied at least in good years and dispersers occur, recovery potential seems quite good given compatible management. In Missouri many prairies are not managed primarily with fire and most seem to be occupied by rather dense populations. All observations suggest that given adequate time and adjacent refugia, burned prairie units normally will be repopulated from nearby unburned units but may perhaps not fully recover for four or more years (e.g. Swengel, 1996, 1998).

East of the former tall grass prairie region, recolonization is probably a moot issue and recovery potential for subspecies IDALIA is best assessed locally at both known occurrences.

Reintroduction has been considered for the New England islands and David Wagner had some success maintaining lab colonies. However given that habitats on all three islands were demonstrably unsuitable for maintaining populations through even a single hurricane, any new population would also be expected to face eradication unless the habitat were greatly improved and enlarged. As Gochfeld and Burger (1997) put it "unless the causes of its decline can be reversed or mitigated, reintroductions are unlikely to lead to stable populations". Such reintroductions are best viewed as a waste of resources. Given regional genetic differences (Williams, 1999, 2002) which probably include differences in habitat use, ALL introductions not using local stock should be opposed for now. According to Richard Smith (pers. com. to Schweitzer, 1990) misguided butterfly enthusiasts were releasing Nebraska regal fritillary stock on Maryland shale barrens (in accordance with the birdsfoot violet myth). No colonies were formed in these utterly unsuitable habitats. Schweitzer and others suspect that introductions from the same Nebraska source account for a few unverified reports near Newport, Rhode Island in the early 1990s.

Preserve Selection & Design Considerations: The habitat must include all essential resources such as violets (apparently tens or hundreds of thousands of plants) and a reliable supply of nectar for the entire summer even during the worst possible drought scenarios. While it has been suggested females can become somewhat dormant during drought periods, there is no real evidence to date that they can live long without nectar and males probably cannot. Thus a constant supply of nectar is probably critical. For this reason try to include some open wet areas with summer flowers regardless of where the violets are. A failure of the nectar supply for even a day or two could cause adults, at least males, to leave or die. Nectar flowers could include exotics or even plantings.

Probably a viable population needs about 50-100 hectares, maybe more where prescribed burning will be used. Swengel's data suggest densities tend to increase above 65 hectares. As discussed above, densities of ten per hectare are uncommon. An ARANK occurrence probably would need about 500 hectares of good habitat. Opler (1981) recommends about the same size for general insect conservation in prairie regions. While Panzer et al. (1995) and Panzer (1998) clearly document that many prairie insects can be maintained on much smaller parcels, it is notable that few of their sites still have regal fritillary. Do not go after only the most pristine prairie portions, but also protect Grade C or semi-degraded portions with violets or nectar flowers. Regal fritillaries will readily use somewhat degraded habitats for both nectar and for oviposition as long as they are still recognizable as prairie.

If prescribed burning will be used, the preserve must be large enough to implement approximately the management recommendations below.

Topographic diversity is highly desirable at least when violets (larval food) span a range of moisture situations. Species of violets probably does not matter but abundance of violets in open habitats is important. If possible include low areas with wetland violets connected to drier habitats with more upland violets such as VIOLA PEDATIFIDA, V. PEDATA or V. SAGITTATA.

The preserve needs to be defensible from factors such as wildfire and drift or direct application of biocides. Proximity to other known regal fritillary sites, especially any within about two kilometers, should be a strong factor in site selection.

Management Requirements: Management for the two known eastern occurrences should be worked out locally. Much information is available for the Pennsylvania site. Management needs for these populations may differ from those of prairie populations. Most likely whatever methods have fortuitously maintained the Virginia occurrence should continue. The Pennsylvania site may prove more problematic and may need reintroduction of partial burning.

The rest of this section covers regal fritillaries on prairie remnants. While there is an emphasis on fire, burning (as currently practiced) is probably not the optimum management method (Swengel, 1996, 1997, 1998) for this and at least some other specialist prairie butterflies and skippers. Nevertheless it is a common practice where regals persist and fire is likely to remain a common management practice in prairie remnants. Schlicht and Orwig (1998) and Kelly and Debinski (1999) document that fire practices utterly inappropriate for this and other prairie fauna (e.g. see management information in these databases for PAPAIPEMA) still persist at least in Iowa and probably explain some regal fritillary absences there. However, no likely accounts of more typical rotational burning actually excluding regal fritillaries from prairie remnants were found during the preparation of this document.

Perhaps sufficiently conservative burning would be as suitable as haying or grazing. Swengel reports that four or more years may be needed for recovery after partial burns, but Schwartz (1998) rejects this interpretation of her data for any species other than ATRYTONE AROGOS IOWA (but see also her accompanying rebuttal). Panzer's (1998) work shows many other fire sensitive prairie insects typically recover by the second season after fire but most of his sites lacked regals. Swengel (1996) states that "regal fritillaries are the least under-represented in recently burned units among [prairie] specialists" which she attributes to vagility. See also Panzer's discussion of the fire attrition hypothesis, which may hold under some conditions (e.g. small sites, only two to three burn units, etc.) for regals and prairie skippers, even though it did not for species he tested. For now, it seems prudent to accept Swengel's finding of longer (five plus years) fire return intervals, pending further research. This slightly affects recommendation number two below, which might otherwise have been set at four or possibly three years. There is no reason to believe that a more natural (summer) fire season would reduce mortality or speed recovery for regal fritillaries even though it probably would for PAPAIPEMA and some others. Swengel (1996, 1998) also argues for consistency of management within a site and heterogeneity of management between similar sites. This would imply some continued use of fire.

These recommendations are fully compatible with the PAPAIPEMA moth EMG (Schweitzer in prep.) which is based in large part on Panzer (1998), but might not be conservative enough for prairie skippers (Swengel, 1996, 1998; Schwartz, 1998). Both of these groups occur in intact prairie communities with regals and need to be addressed in burn unit layout.

1) Use four or more roughly equal sized burn units with violets well distributed among them. In exceptional cases three units could be tried, but monitor carefully for several rotations before settling on such a practice. If concentration of more than a third of the breeding habitat in one unit is unavoidable gently wet some major violet patches before burning that unit.

2) Allow five or more rest years before reburning a unit, in general burn no more often than the minimum the vegetational community really requires.

3) Do not burn adjacent units in consecutive years.

4) Do not reburn skips within burn units.

5) Avoid burning for a year or two if monitoring shows regal fritillary numbers to be unusually low the previous season.

6) Swengel also suggests using rather linear units, which should be easier to recolonize.

7) Do spring burns before violet new growth appears.

8) If use of three or more burn units would really be impossible, faunal considerations including regal fritillary point to a need for a less lethal management tool.

9) Strongly consider other management methods for prairie remnants of less than 50 hectares that still harbor regals and/or specialist skippers since other methods (at least haying) will probably produce higher (more sustainable) densities and thus increase the probability of persistence.

10) Do not change over to burning if haying or some other method has been used to manage a site for more than a decade unless there is a compelling reason to believe current management is significantly suboptimal.

Not much information was found regarding haying and grazing on prairie fauna by Moffat and McPhillips (1993) but Swengel (1996, 1997, 1998) does address effects of haying in general on regals and she offers a few observations on grazing. The Missouri Department of Conservation and other agencies in that state manage some prairies quite successfully primarily with rotational haying. It is probably cause and effect that regal fritillaries are especially abundant in that state (Swengel, 1996, 1997). Many Missouri prairies were managed as hay meadows for decades prior to becoming preserves and almost certainly this is a factor in the success of regal fritillary there. The Department guidelines for haying in managed prairies that should be consulted. They have much information on the botanical effects of haying at various seasons. In general haying operations are conducted in July. No more than half the acreage is hayed in any summer and haying is conducted on a two to three year rotation. One added caution, avoid haying when it is too hot, cool, wet or cloudy for adult regal fritillaries to escape easily. Sunny days between 1000 and 1600 hours at 20 to 32 degrees Celsius are strongly recommended. Missouri also has recommendations for cattle grazing that would be worth considering, although there probably should be rotational rest years inserted.

Where alien cool season weeds are not a major problem, frequent, up to annual, dormant season mowing to a height of about four inches is strongly recommended for consideration. Eastward, this method inadvertently maintains many impressive, even spectacular, assemblages of grassland Lepidoptera in states like New Hampshire, New York and New Jersey (Schweitzer pers. obs.). There is no known mechanism by which dormant season mowing could kill hibernating regal fritillary larvae or most (not all) prairie Lepidoptera other than limited mortality from being run over by the wheels of the mower. An important consideration if thatch is not removed is that violets not be "smothered."

Monitoring Requirements: The need to monitor depends on so many factors relating to management, habitat and population factors that decisions need to be made case by case. Monitoring over several rotations is especially recommended when changing from some other management practice to rotational burning.

Since this is such a large and conspicuous species there is seldom any valid reason for not at least noting presence on any preserve visited by staff during the daytime in June, July or August. Hardly any skill is needed to simply note roughly how many were seen. For stable large prairie populations this may well be enough. Methodology is discussed below for situations in which more intensive monitoring is needed. Report occurrences to the state Natural Heritage Program. This species should be tracked rangewide.

As with almost any butterfly a reliable estimate of population size will usually require mark-release-recapture (MRR) methodology (Gall, 1985). If a Jolly-Seber based analysis will be done, at least three field sessions are necessary and five or more are strongly recommended. A Lincoln Index may be possible with only two. Census and transect methods are used primarily to document trends or to compare sites (e.g. appropriately in Swengel's work) and any population estimates based on them are highly suspect. Unless censuses actually record a large majority of adults in the area covered (or the percentage overlooked is known) the numbers generated are not real daily population size estimates. However, it would be very reasonable to conclude (e.g. for EO ranking) that the daily population is at least the number observed and obviously the brood size is at least the maximum daily observation. If a reasonable census was done for only one sex (usually males) assume that the real sex ratio over the season is close to one to one. While most mark-release-recapture models account for recruitment (new eclosions and immigration) and loss (death, emigration) and even estimate residency rate (PHI in Jolly-Seber model), census methodologies generally cannot account for unseen individuals or turn over.

For a serious estimate of a substantial population mark-release-recapture (MRR) must always be used. Be prepared to include use of software able to run the Jolly-Seber analysis and ideally another such as Manley-Parr (see Gall, 1985), although it may turn out that a simple Lincoln Index will suffice. Kelly and Debinski (1999) used two sample Lincoln Index but did not report associated error. While they used mostly consecutive days due to their field schedule, a longer interval would allow better mixing and maybe a better estimate. Sexes are normally analyzed separately and females may be too sedentary to be practical as Schweitzer (based on his own work) suspects to have been the case in the Nagel et al. (1991) study. This probably explains Kelly and Debinski's inability to find many females. Barb Barton also had problems working with females in Pennsylvania, although Dale Schweitzer did not have difficulty locating them in Maryland, Massachusetts or Rhode Island. In the latter two states this clearly reflects his timing. Regal fritillary adults are very long lived for butterflies with many individuals living three to six weeks. The much shorter estimates of Nagel et al., 1991 are invalid due to flawed PHI estimates (see ADDL.TOPICS). Barb Barton's maximum longevity estimates of 57 days for males and 69 days for females (as cited by Kelly and Debinsky, 1999) seem very reasonable for most populations although obviously mean longevity is lower. In most cases emergence of new adults is spread over probably about two-three weeks for each sex. Therefore it is possible to time MRR late enough that at least recruitment is not a significant factor over the time involved. Low to moderate loss will not seriously affect estimates as long as marked and unmarked butterflies are lost equally. In such cases use of a Lincoln Index is reasonable. This estimate and its variance are easily calculated on any hand calculator (see Gall, 1985 and additional topics). Actually Schweitzer's (1983, 1984a,b) MRR work with regals suggests that the Lincoln Index is occasionally superior to the more complex Jolly-Seber formula for female regal fritillaries over periods of about a week since it does not rely on potentially unreliable PHI estimates. It appears a two sample Lincoln Index estimate for females is very practical late in the season when they are most active. Males should be even easier once eclosion has ended. If time and human resources are adequate, a prolonged Jolly-Seber based approach (e.g. Barb Barton's effort in Pennsylvania) is probably best. A Jolly-Seber based approach should involve samples every few days through the main flight season of at least one sex-about a month. Males are much easier to work with as they make themselves more conspicuous! MRR estimates are very sensitive to low mark intensity or small samples sizes and as a result obviously invalid daily estimates occasionally occur (such as the 1400 plus or minus 1022) of Nagel et al. (1991). See additional topics. Anyone considering mar-release-recapture work with this species should also review Barb Barton's unpublished reports to Pennsylvania Natural Diversity Inventory and accompanying materials from Dale Schweitzer and Richard Arnold.

MRR teams for regal fritillary should consist of two or three persons working together. When marking regal fritillaries it will usually be necessary to run down flying or flushed individuals. This is difficult for one person but is usually fairly easy if a second person positions him/herself to ambush the butterfly. Be sure to get close enough for an accurate swing and do not swing wildly or excessively hard which risks disabling the butterflies (which will be immediately obvious upon release [disabled individuals should not be released and must be treated as not released in any MRR calculations]). Females at least may become apparently exhausted and simply drop from the air. When marked and released these often move rather quickly to flowers. Their subsequent recapture rates are normal. Nagel et al. (1991) also gives some useful tips for the field aspects of MRR with this species. Regals are very easy to handle and mark without injury after capture. If the capture point is distant from where a chase started, consider releasing near the former. Schweitzer recommends use of black permanent marking pens such as Sharpie extra fine point and that all butterflies be promptly marked and released and not stored.

A variety of census methods including transects and "walks" can be used for relative population comparisons. Census methods are very much easier than mark-release-recapture and for that reason should be used if knowing actual population size is not necessary (for example in Swengel's work). If done competently, neither census nor mar-release-recapture poses any significant risk to populations over about 20 adults. Census techniques are reviewed by Gall (1985) and treated in the primary literature such as Pollard (1984), Thomas (1983) and especially the regal fritillary-specific works of Swengel (1990, 1991, 1996, 1997, and 1998) and references therein. For regals, possible concentration near flowers such as thistles or milkweeds and probable seasonal shifts to track changes in nectar must be strongly considered in any sort of census or transect. A rigidly fixed transect that fails to adequately cover nectaring areas may not work well. Swengel did not find this a major problem in prairies where nectar was well distributed although she notes some concentration around thistles, but eastward (e.g. Schweitzer's work on Nantucket and Block Island) adults sometimes were highly concentrated at localized and seasonally shifting nectar sources.

In many cases useful data might be obtainable from annual "fourth of July" butterfly counts sponsored by the North American Butterfly Association (NABA) which are modeled after Christmas bird counts. Contact local count coordinators and see if a suitable route and timing are possible or already in place. A problem with such counts is varying dates and inconsistent coverage from year to year, but if asked perhaps a couple of persons would take responsibility for doing it right at regal sites. NABA counts should be used very cautiously for hairstreaks, skippers and others that cannot be reliably field identified by non-experts but this is not a valid concern with regals. Some regal fritillary sites in the Midwest are already included in NABA counts.

Management Research Needs: It could prove extremely useful to further investigate the relationship between violet numbers and regal fritillary numbers and to better quantify for any independent area effect.

It would be very useful to investigate why (or if) regal fritillaries require four or more years to recover after partial prescribed burns while most other prairie Lepidoptera and Homoptera (at least those available to Panzer, 1998) do so in less. A possible hypothesis would be impacts of fires to the violet foodplants. Or possibly adults benefit from cover provided by shrubs or accumulated standing dry stems.

Since there was a lot of heterogeneity in the fire regimens among Swengel's study sites (apparently including 50 percent and 100 percent burns and return intervals as low as two years), it would be useful to compare the suitability of a conservative fire regimen such as recommended above (see MGMT.REQ) to haying, mowing or grazing. While Swengel's data show that sites managed with rotational burning as practiced in the 1980s to mid 1990s generally have lower regal fritillary numbers as compared to other methods, it is possible a slight relaxation of fire frequency and use of a few more burn units would eliminate this effect. Possibly this issue could be addressed from Swengel's extensive existing data, for example by comparing only sites with four or more burn units and rotations with five (or even four or three) rest years to sites managed by haying or grazing. No prairie manager concerned about invertebrates is likely to promote a one or two year rotation anyway although such practices still persist in some places (e.g. Schlicht and Orwig, 1998; Kelly and Debinski, 1999).

More research into why Iowa adults are smaller than others (Kelly and Debinski, 1999) is needed since this almost certainly affects female fecundity and could be contributing to the decline there. The violet density explanation seems most likely. As a corallary, perhaps conditions most conducive to high fecundity could be documented.

Obviously it would be very useful to better understand why the eastern subspecies S. I. IDALIA has collapsed to near extinction. However, such research may now be impossible since so few (perhaps only two) occurrences remain.

While such research would be difficult, it would be useful to better document the circumstances under which adults, especially females, disperse from their natal habitats. For example does dispersal rate increase when densities become high? Also it would be useful to know how effective dispersers are at finding and colonizing new sites.

It would be useful to know if prairie regal fritillary females can in fact aestivate sufficiently to survive without nectar during severe droughts as suggested by Nagel et al. (1991) and Swengel (1997). If they cannot, as should be assumed for now, an uninterrupted nectar supply is critical.

It would be useful to determine definitively whether or not late instar larvae make use of any foodplants other than violets when they are forced to look for new food resources.

Biological Research Needs: Effects of management techniques on butterfly and violet populations (fire, mowing and grazing). Especially how long is needed to recover from prescribed burns. Possible use of grazing to maintain this and other fire sensitive prairie Lepidoptera.
Additional topics: For a two sample Lincoln Index

N=[(M+1)(n+1)/(m+1)] -1 where

N is the population estimate, M is the number marked and released in the first sample period, n is the total number of individuals in the recapture sample, and m is number of marked individuals in the recapture sample. The variance is: var

N=[(M+1)(n+1)(M-m)(n-m)]/[(m+1)(m+2)]. The 95 percent confidence interval is plus or minus twice the square root of var

N. In any MRR only marked individuals are ever released on any day and recaptures must be random. Multiple captures of an individual in the same sample are treated the same as single captures. Smaller 95 percent confidence intervals will result from high M/N (and therefore m/n) ratios. While individual recognition is unnecessary with a Lincoln Index, individuals should always be numbered and recorded so other MRR formulae can be used. The advantage of the Lincoln Index is that only a hand calculator is needed and sometimes a reasonable estimate is obtainable from only an initial intensive marking period of one or two consecutive days, followed by a single recapture sample a few (generally 1-7) days later.

When eclosion is substantial, a model which accounts for recruitment and residency such as Jolly-Seber or Manley-Parr should be used (see Gall, 1985). These require at least three samples and should give good estimates for days two through next to last. So a five sample effort should produce three reliable daily estimates and sometimes the terminal one proves similar. Error estimates are calculated for all but the first and last daily estimates, but not for the overall brood estimate. An intensive effort should always be made to achieve high mark intensity (M/N) during the first field session. If possible recapture samples should contain 50 percent marked butterflies by the second recapture period. When using a Jolly-Seber model, if possible with available software, use both the Scott (1973) and Tabasnik (1980) method for calculating PHI (residency rate) values. These occasionally produce quite different results but it should be apparent which one is more reliable. Although capping PHI at 1 makes biological sense, it may create a negatively biased mean.

Review of the RoweSanctuary, Nebraska estimates (Nagel et al., 1991) is instructive for some potential MRR problems. The June 25 estimate (1400 +/- 1022) being so much higher than earlier and later makes no sense considering the basic biology of regal fritillaries. The huge error also shows it is unreliable. Such inflated estimates with huge errors can result from low initial mark intensity, small recapture samples, or long gaps during which emergence occurs between samples. The average of the other three estimates (231, 385, 300) which are similar but with large errors, gives 305 males. Raw data given are insufficient to determine exactly what went wrong but sample gaps were probably not the problem. Their PHI (residency rate, capped at 1) estimates are also very unreliable so their longevity estimate is invalid and a reliable brood size estimate is unavailable. L. F. Gall (pers. com. to Schweitzer, March 1992) confirmed the PHI problem and also pointed out that their statement that SE estimates could not be made (e.g. for July 7) "due to 0 in the denominator" shows they failed to use a continuity correction to eliminate zeros, which probably inflated all their estimates by about 30-40 percent. This brings the estimate down to around 200 males (400 adults) or less. So Rowe Sanctuary was supporting more like 400 adults in 73 hectares, which would still be among the four highest mark-release-recapture estimates found in preparing this document (highest was 494, Kelly and Debinski,1999). Even the number (292) actually marked is sufficient to establish this as an important occurrence.
Population/Occurrence Delineation
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Group Name: Speyeria Butterflies, Generic

Use Class: Not applicable
Minimum Criteria for an Occurrence: A location where the species occurs or has occurred with potential for persistence or regular recurrence. Minimally a location with violets (larval foodplant), nectar flowers and suitable overall habitat for the particular species where presence has been verified by specimen (strongly preferred westward) or expertly identified photograph. For some species in eastern North America sight records from experienced observers are acceptable. Most viable EOs will be at least 10 hectares and some taxa such as S. IDALIA require much more space (as is also suggested by Layberry et al., 1998 for S. EDWARDSII).
Mapping Guidance: Use the unsuitable habitat distance only if there is really no suitable breeding habitat between sites and adults do not regularly visit the intervening area for nectar. For example for a prairie or woodland taxon the suitable habitat distance should be applied between high quality habitat patches separated by a landscape containing marginal or degraded habitat patches or abundant flowers such as thistles.If the habitat is a feature clearly contained within an overall natural community matrix, such as openings in chaparral or woodland, then all such patches within that community occurrence should generally be considered a single metapopulation EO and the suitable habitat distance used The EO boundaries can be based largely on the community boundaries but might include additional nectaring areas if these are a locally limiting resource and not abundant in the primary habitat. Consult habitat and food comments fields for species-specific information on what constitutes suitable habitat when mapping occurrences for individual species. Presence of genus VIOLA is a critical habitat feature, but as far as known the exact species of violet is not important.
Separation Barriers: This definitely varies by species and cannot usually be known. Some open country species (such as S. IDALIA) will not enter wooded areas, but might fly over or around them. Developed areas, including lightly urbanized ones, cannot be assumed to be barriers as wandering adults will enter them to visit flower gardens. Due to high temperatures and lack of flowers lowland deserts probably can be considered significant barriers to most species.
Separation Distance for Unsuitable Habitat: 4 km
Separation Distance for Suitable Habitat: 10 km
Alternate Separation Procedure: In arid regions consider whether hot arid terrain might actually be a thermal barrier and not merely unsuitable. If this appears to be the case a separation distance as small as 2 km might be appropriate.
Separation Justification: See separate documentation for S. IDALIA. Individuals of that species have been documented several times as moving a few kilometers in one day either one way or round trip during marking studies by Barb Barton in Pennsylvania and by Dale Schweitzer in New England. Documentation is less for other species but individuals several kilometers out of habitat are frequently seen for some of the species such as S. CYBELE eastward. At least the females are long lived and apparently move about during their late summer oviposition season. On the other hand adults are not commonly season more than a kilometer or so out of habitat if the intervening terrain is obviously different. Undoubtedly movement potential does vary among species and cold climate species probably are less able to travel due to temperature and generally shorter flight season. The more extreme habitat specialists and relictual populations are probably sedentary. A further serious complication is that habitat that is completely unsuitable for breeding (e.g. lacks violets) may contain a lot of nectar and thus should probably be considered suitable habitat in the context of separation distance. Adults of species such as S. DIANA, IDALIA, CYBELE, ATLANTIS frequently visit such places. The figures are educated guesses based on general experience.
The rather low figure of two kilometers takes into account the rather discrete habitat preferences of most of the species. Speyeria are not likely to utilize any patch of foodplants in inappropriate habitat context. Even S. CYBELE, probably the least specialized species, does not use extensive violet populations in highly disturbed habitats such as lawns or most city parks, even when these are mostly not subject to mowing or other regular disturbance.

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): 2 km
Inferred Minimum Extent Justification: Use with caution and some knowledge of the adult and breeding habitat. For a flying animal easily capable of covering 1-6 kilometers in a day that lives around one-two months and with occurrences being populations of generally hundreds of adults, it would be unreasonable to assume truly suitable habitat without large gaps would remain regularly unoccupied even if parts of it were vacant in a given year (such as in some cases after fall or spring fires). Apply the 2 km radius only for extensive suitable habitat. If the habitat does not extend that far do not infer presence. For habitats less than 400 hectares assume full occupancy. If the nature or extent of the local habitat is unclear, select a smaller inferred extent. Persistent greater fritillary occurrences usually occupy more than 50 hectares and often several hundred.
Date: 19Jul2001
Author: Schweitzer, D.F.
Notes: These Specs are meant to cover most of the G4 and G5, and some G3, species within this large genus. The rarer species usually have their own Specs and are often better studied. There is substantial species or subspecies specific literature on this genus, dealing mostly with the rarities. If better taxon-specific local information is available, use it rather than these Specs.
Population/Occurrence Viability
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Excellent Viability: Moot. Very few if any current occurrences approach even the original average considiton in the prarie region and none approach what would originally have been good occurrences.
Good Viability: Apply to exceptionally good remnant occurrences that are more likely than most to persists and maintain whatever genetic diversity they still have and are large enough in numbers and extent that recovery would be likely after a catastrophic event such as a wildfire killing more than 90% of the population. A prairie remnant containing at least 100,000 violet plants and which in a given year will contain at least 500 acres of good habitat unburned for at least the previous two years, and which has been documented to produce at least 500 adults some years, and not much less than 200 in the worst documented years. Furthermore the remnant is managed without fire or is subject to no more than 30% burned in any two year period. The remnant must have some topographic diversity and if it is managed with fire, it should contain major violet concentrations in at least five burn units with violet microhabitats ranging from dry-mesic or xeric to hydric within at least three of these burn units. If the remnant is managed by growing season haying, no more than 50% should be hayed in any one season, and if it is managed by grazing, no more than a third should be grazed in one year and there should be a rest year before a unit is grazed again. As far as known dormant season mowing could be up to 100% annually as long as cuttings did not smother violets. Additionally the site must have reliable nectar resources, either widely distributed or at least in two or more burn units, sufficient to provide an uninterrupted nectar supply throughout the adult flight season even in severe drought years.
Fair Viability: This category should include all occurrences reasonably likely to persist but not reaching the B-SPECS. CRANK EOs are to be considered conservation worthy and if quality is being depressed by management practices, these should be re-evaluated. Minimum CSPECs probably should include at least 50 hectares total size (perhaps sometimes could be less where managed without fire). There must be at least three, perhaps rarely two, burn units and a total rotation of at least three or four years. There probably need to be at least 50-100 adults most years so that the population does not crash to extinction in very bad years. The remnant probably needs to have a few tens of thousands of violet plants with major large violet patches within at least 2 burn units which are burned at least two years apart. Violets may be more highly concentrated if the site is not subject to fire. Also most larger occurrences with inappropriate fire regimens or no management at all should for now be ranked C. In general use CRANK for small occurrences that are reasonably likely to persist or for larger ones that are likely to persist for the next decade despite somewhat inappropriate management. Such larger sites usually could be improved with management. In general occurrences subject to complete burns at any frequency should be ranked D and this rank should be strongly considered if there are only two burn units burned less than four years apart.
Poor Viability: Occurrences that are likely to die out due to normal population fluctuations or due to management practices or both. This includes sites seldom to never producing 100 adults (or are known to frequently produce less than 20) or which are much under 50 hectares or where all habitat is burned in a single year, and almost all occurrences where rest interval between fires is usually only one or two years per unit. Also most sites that support populations some years and not others, but in such cases consider whether site is possibly part of a larger one.
Justification: Part about violet numbers is from Swengels' work. Otherwise this is influenced by both hypothetical considerations of what might ne a very good occurrence and some of the better ones recently documented. Emphasis is on separating B from C.
Key for Ranking Species Element Occurrences Using the Generic Approach (2008).
Date: 15Feb2007
Author: Schweitzer, D.F.
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 16Mar2008
NatureServe Conservation Status Factors Author: Schweitzer, D.F.
Management Information Edition Date: 23Feb2000
Management Information Edition Author: SCHWEITZER, D. F.
Management Information Acknowledgments: Ann Swengel provided several unpublished reports (some cited herein and some not) and reprints of her published work for which the preparer is most grateful. She also provided useful comments on a much earlier (1992) draft of this document. Some information comes from conversations Barb Barton, although her reports to Pennsylvania Natural diversity Inventory were not reviewed in detail. While most of this document was prepared from published or otherwise acknowledged reports, some information and observations from the preparer himself are unreferenced. When Ann Swengel's work is mentioned without specific reference, the implication is that several of her cited works would be relevant. Information provided by Pennsylvania, Michigan, Maryland, North Carolina and Virginia Natural Heritage Programs was used in range and status assessments.
Element Ecology & Life History Edition Date: 24Jan2005
Element Ecology & Life History Author(s): SCHWEITZER, D. F.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

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