Endangered Resources Program Species Information
Frigga Fritillary (Boloria frigga)

Frigga Fritillary Photo by Mike Reese. Check the photos tab for additional photos.
Photo © Mike Reese

Overview

Species Overview

Frigga fritillary ( Boloria frigga ), a State Special Concern butterfly, has been found in large, open muskeg areas with bog birch (Betula pumila), bog willow (Salix pedicellaris), bog laurel (Kalmia polifolia) and bog rosemary (Andromeda glaucophylla). Adults fly from the last week of May to mid June in Wisconsin.

Status and NHI Documented Occurrences in Wisconsin

The table below provides information about the protected status (State and Federal Status) and the rank (S and G Ranks) for Frigga Fritillary (Boloria frigga). See the Working List Key for more information about the abbreviations used. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. For invertebrates, dots depict locations from the "Invertebrate Atlas," a database with occurrences of rare and common aquatic and select terrestrial invertebrate species found in Wisconsin and adjacent areas. While the invertebrate atlas is a quality assured database, not all records have been verified. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Summary Information
State Status:	SC/N
Federal Status in Wisconsin:	none
State Rank:	S2
Global Rank:	G5
Tracked by NHI:	Y
Species of Greatest Conservation Need:	Y

Documented locations of Boloria frigga in the Natural Heritage Inventory Database as of April 2009.

Detailed Information

Identification: Adults are orange above with black markings; basal half of the hindwing is black. The underside of the hindwing has a submedian cluster of faint yellowish-white spots dusted with maroon with the outer half becoming predominantly purplish. Tip of forewing is pointed. Similarly-colored crescents (Phyciodes spp.) and checkerspots (Chlosyne spp.) in Wisconsin typically display more black scaling on the outer borders of the upper side of the wings than do the fritillaries, in which the black markings are most often broken into an array of discrete spots. The underside of the hindwing must be viewed to separate the species. Wingspan: 38-48 mm. Length of forewing: 20-26mm. All Boloria larvae have rows of branched spines with no mid-dorsal row and no spines on the head. B. frigga larvae are black with black spines and a purple line along each side.

Similar Species: Only the Freija fritillary (Boloria freija) and Frigga fritillary (B. frigga) have black on the basal half of the hindwing. B. freija is a smaller butterfly with white markings on the hindwing below. The underside of the meadow fritillary (Boloria bellona) is similar, but lacks the black basal half of the hindwing.

Habitat: Poor fens supporting bog birch (Betula pumila), bog willow (Salix pedicellaris), bog laurel (Kalmia polifolia) and bog rosemary (Andromeda glaucophylla). In Wisconsin the Frigga Fritillary seems closely tied to bog willow. Many sites occur along the margins of larger bogs.

Nectar Source: Adults have been seen nectaring at bog rosemary and Labrador tea in Wisconsin (Johnson, pers. obs.), and bog laurel and bog rosemary in Michigan (Nielsen 1999).

Host Plant: In Michigan oviposition has been observed on bog rosemary, bog laurel, and cranberry (Vaccinium spp.) Caterpillars have been partially reared on bog birch (Nielsen 1999). Most closely associated with bog willow (Salix pedicellaris) in Wisconsin.

Associated Species: Silver-bordered fritillary (Boloria selene), bog fritillary (Boloria eunomia) and Jutta arctic (Oeneis jutta) in Michigan (Perkins 2003). Red-disked Alpine (Erebia discoidalis) may be also be present early in the flight of the Frigga Fritillary.

State Distribution: Ashland, Bayfield, Douglas, Forest, Iron, Langlade, Lincoln, Oneida, Price, and Vilas counties. They may be common in areas supporting large amounts of bog willow (Salix pedicellaris), but seem rather uncommon otherwise.

Global Distribution: Circumpolar in tundra and boreal forest. Found across most of boreal North American from Alaska to Labrador, south to northern Wisconsin, Michigan, and Minnesota. Also found at higher elevations in the Rocky Mountains south to Colorado.

Threats: Disruption of bog hydrology.

Phenology: Adults fly from the last week of May to mid June in Wisconsin.

Life History: Eggs are laid singly in the leaf litter near the food plants. Larvae feed only at night.

Survey Guidance: On cloudy days Friggas fly very little, spending much of their time sitting on sedges. They have been observed flying under overcast conditions with temps. in the mid-50's (Johnson pers. obs.). On sunny days the males actively patrol patches of bog willow in search of females, and frequently bask on sedges or nearby shrubs. They seldom stray far from their preffered micro-habitat. They have been found to be locally common in a few sites, but most records are of small numbers of individuals. New county records should be documented with voucher specimens.

Inventory, Monitoring and Research Needs: Locate additional populations. A considerable amount of potential habitat in Wisconsin has not been surveyed. There are likely a significant number of undiscovered populations throughout northern Wisconsin.

Additional Information: B. frigga saga is the subspecies in Wisconsin.

Information originally presented as part of the Online Field Guide to Rare Lepidoptera: Bogs and Barrens.

Photos

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