Plants and Animals

Speyeria idalia Regal fritillary

species photo
David Iftner

Key Characteristics

Wingspan 3.0-4.0 inches (7.5-10 cm). The upper surface of the forewing is reddish orange with black and white spots. The hindwing is black with white spots in females and reddish submarginal spots in males. The undersurface of the hindwing is blackish gray with white spots (not metallic silver). The caterpillar is velvety black with yellowish orange blotches and is covered with orange-based silver spines tipped in black.

Status and Rank

US Status: No Status/Not Listed
State Status: X - Presumed extirpated (legally 'threatened' if rediscovered)
Global Rank: G3? - Vulnerable (inexact)
State Rank: SH - Possibly extirpated


CountyNumber of OccurrencesYear Last Observed
Berrien 1 1917
Branch 1 1947
Calhoun 2 1949
Cass 1 1981
Jackson 2 1958
Kalamazoo 1 1948
Lenawee 3 1965
Livingston 3 1956
Montcalm 1 1965
Newaygo 4 1989
Oakland 2 1949
Shiawassee 2 1975
St. Joseph 3 1984
Washtenaw 4 1958
Wayne 1 1931

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Prairie or open environments frequently in sandy regions. Meadows, old fields, and floodplain forest openings and edges. Adults have been observed on alfalfa, common milkweed, blazing-star, and butterfly weed. Various species of violets are used as larval hosts.

Specific Habitat Needs

Host plant needed in: Dry sand prairieHillside prairieMesic sand prairieOak barrensSouthern wet meadow.

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

The Regal fritillary is scattered across much of the southern Lower Peninsula, but it occurs sporadically and generally in low abundance. This species has been in decline across the Great Lakes region and its status in Michigan is currently undetermined. This species also is considered globally rare. Threats to this species include habitat loss, degradation and/or fragmentation due to conversion to agricultural lands, altered fire regime; industrial, residential and/or recreational development; and encroachment by invasive species. Additional threats to this species include incompatible natural resource management, use of herbicides and pesticides and lack of scientific knowledge about the species. Surveys are needed to determine this species' current status, abundance and distribution. Research to obtain more information about this species' life history and ecology and efforts to assess threats to this species also are warranted. The sites at which this species has been documented should be protected and maintained. Adequate suitable habitat at known sites should be maintained including sufficient densities of the species' host plants. Prescribed fire is an important management tool for the habitats with which this species is associated, but care should be taken to ensure that occupied areas are only partially burned.

Active Period

Flight from fourth week of June to second week of September

Survey Methods

In Michigan, adults have been documented from mid- to late June to mid-November, although this is probably extreme. Larvae are nocturnal feeders. By day, the larvae hide in leaf litter at the base of the food plants. The flight appears more fluttery than that of the other species. Adults have been observed on alfalfa, common milkweed, blazing-star, and butterfly weed. Various species of violets are used as larval hosts. Visual surveys should include checking for adults or larvae on or near nectar sources and host plants.

Visual, aerial net

Survey Period: From fourth week of June to second week of September

Time of Day: Daytime


Survey References

  • Klots, A.B. 1951. Peterson Field Guides: Eastern Butterflies. Houghton Mifflin Company, Boston. 349pp.
  • Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.

Technical References

  • Bouseman, J.K. and J.G. Sternburg. 2001. Field Guide to Butterflies of Illinois. Illinois Natural History Survey, Champaign. 264pp.
  • Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
  • Glassberg, J. 1999. Butterflies through Binoculars: The East. Oxford University Press, New York. 242pp.
  • Klots, A.B. 1951. Peterson Field Guides: Eastern Butterflies. Houghton Mifflin Company, Boston. 349pp.
  • Nielsen, M.C. 1999. Michigan butterflies and skippers: A field guide and reference. Michigan State University Extension Bulletin E-2675, East Lansing. 248pp.
  • Stehr, F. W. 1997. Michigan Lepidoptera Survey Sites and Seasonal Occurrence of Michigan's Listed Species Annual Report 1997. 30 pp.+ MI Lepidoptera Survey Data Collection Form