Brachionycha borealis Smith, 1899
Boreal Fan Moth
NatureServe Global Rank: G4
Virginia State Rank: S1S3
VA DGIF Tier: None
Federal Legal Status: None
Virginia Legal Status: None
Description: The Boreal Fan Moth is a medium-sized (50 mm) gray moth with a distinctive pattern. The wings are various shades of light gray with black scalloped am and pm lines, as well as other lines and dashes. The hind wing is lighter gray with dark spots along the margin of the wing and a larger dark patch in the upper middle part of the wing.
Similar species: There are no other similar species in North America, and there is no apparent difference in appearance among moths from the various portions of its disjunct range. The arrangement of lines on the wings can be used to distinguish similarly colored species.
North American Range: This species ranges from Montana and southwestern Canada to the eastern United States and south in several counties in West Virginia and Augusta and Rockbridge counties in Virginia.
VA Observations by Locality: Augusta | Rockbridge
Flight season and broods: Adults appear in April and it has been noted to be before Red Maples and Aspens flower, and only lasting for fourteen or fewer nights.
Habitat and Food Plants: The habitat in this part of its range appears to be in cold mountain oak forests at higher elevations. Larvae of this moth feed on spring foliage of oaks, blueberry, and other plants. It is the only species of its subfamily known to feed on plants from more than one family, and even to feed on other caterpillars.
Behavior and Ecology: Larvae occur in the spring, feed on new growth, and pupate in the soil mid-June. It is unknown if this species overwinters for more than one year. Adults will come to light in temperatures as low as 9.5°C (49°F).
Population trend and potential threats: This moth is better described as local and poorly understood, rather than as rare. Global warming, spring fires (threat to post larval stages), and pesticide application for the suppression of Gypsy Moths (Lymantria dispar) are all potential threats to the Boreal Fan Moth.
Management practices: Management for this species varies with habitat, but in Virginia, a better understanding of the implications of pesticide applications would be most important.
References: Bug Guide. 2003. Iowa State University Entomology. At: www.bugguide.net/node/view/514737. Accessed: 13Apr2013
Moth Photographers Group at the Mississippi Entomological Museum at Mississippi State University. Web application at: http://mothphotographersgroup.msstate.edu/large_map.php?hodges=10011 Accessed: 13Apr2013
Schweitzer, D. F., M. C. Minno, and D. L. Wagner. 2011. Rare, Declining and Poorly Known Butterflies and Moths (Lepidoptera) of Forests and Woodlands in the Eastern United States. USDA Forest Service, Morgantown, WV, FHTET-2011-01. 517 pp.