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Contact information
For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
For information on Wisconsin's rare invertebrates, contact:
Jay Watson
Conservation Biologist

Regal Fritillary (Speyeria idalia)



Regal Fritillary (Speyeria idalia), presently listed as a Federal Species of Concern and Endangered in Wisconsin, has been found in large grassland areas with tallgrass prairie remnants or lightly grazed pasture lands containing prairie vegetation. The larval food plants are violets, primarily prairie violet (Viola pedatifida), birdsfoot violet (V. pedata), and arrowleaf violet (V.sagittata). Adults are present between late June and early September with peak flight usually the first part of July.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Regal Fritillary (Speyeria idalia). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Speyeria idalia in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusEND
Federal Status in WisconsinSOC
State RankS1
Global RankG3?
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: Regals are large butterflies with orange background on the forewings and dark background on the hindwings. The thick black marginal area on the upperside of the wings contains orange spots (male) or white spots (female). The underside of the hindwings shows the large silver spots typical of many fritillary butterflies. However, the background is evenly dark or rusty red without a lighter marginal band on the lower hindwing. Only one other fritillary species shows this ventral wing pattern but its upper surface lacks the dark marginal areas of the regal. The adult wingspan is about 2.75-3.50 inches (7.1-9.0 cm).

Habitat: Large grassland areas with prairie remnants or lightly grazed pasture lands containing prairie vegetation where topography often includes hills and valleys, are habitats used by regals in Wisconsin. The larval food plants are violets, primarily prairie violet (Viola pedatifida), birdsfoot violet (V. pedata) and arrowleaf violet (V.sagittata). Regals are strong fliers and appear to require large areas to support a population though area size depends on availability of quality habitat that will vary according to local vegetation and management.

State Distribution: Occurs in Crawford, Columbia, Green, Iowa, Portage, and St. Croix Counties.

Phenology: Adults are present between late June and early September with peak flight usually the first part of July. Mating takes place before August first. Oviposition occurs near violets during August and September. The newly hatched larvae seek shelter in or under the leaf litter and immediately go into diapause. The following spring when temperatures rise, the larvae begin to feed at night on the violet leaves until pupation in early summer.

Management Guidelines: Survival of regal fritillaries in Wisconsin will depend on protection and enhancement of large areas of suitable grassland habitat. Habitat fragmentation and loss of prairie communities to development and intensive agriculture contribute to the decline of the species. Grassland management activities must be adjusted where regals are established in order to maintain the populations. Sites that experience frequent controlled burns (less than 5-7 year rotation) exhibit reduced numbers of butterflies therefore burn management should be avoided on regal sites. Light grazing, infrequent mowing and/or localized brush cutting are positively associated with regal abundance on sites in Wisconsin.



Regal Fritillary

Male regal fritillary.

Photo by W.A. Smith, WDNR.

Regal Fritillary

Female Regal Fritillary nectaring on rough blazing star.

Photo © Ann Swengel.

Regal Fritillary

The Regal Fritillary, a globally rare prairie butterfly, nectaring on orange milkweed.

Photo © Ann Swengel.

Regal Fritillary

Important populations of the globally rare regal fritillary inhabit prairies in the Southwest Savanna.

Photo © Mike Reese.

Regal Fritillary

Regal Fritillary, above - Muralt Bluff Prairie State Natural Area, Green County.

Photo © Mike Reese.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Regal Fritillary. Only natural communities for which Regal Fritillary is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Ecological landscape associations

The table below lists the ecological landscape association scores for Regal Fritillary. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Regal Fritillary occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, October 08, 2020