Speyeria idalia
Regal fritillary
Image of Speyeria idalia

Photo by 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

  • State Status: E
  • State Rank: SH
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
St. Joseph31984
Distribution map for Speyeria idalia

Updated 5/15/2018. 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 Southern wet meadow, Oak barrens, Mesic sand prairie, Hillside prairie, Dry sand prairie

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.


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.

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Sep 25, 2018]


Survey References

Technical References

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