Schinia indiana (Smith, 1908)
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Basis for Listing
The phlox moth is considered to be rare throughout its limited range, which extends from Minnesota through Wisconsin, Illinois, Indiana, and Michigan, with apparently disjunct records from Arkansas and Texas. There are no recent records from Arkansas, Texas, or Illinois, and the species is considered imperiled to critically imperiled in the other three states east of Minnesota (NatureServe 2008). The phlox moth was first documented in Minnesota in 1976, and has been found at only four other locations since then. All occurrences are in native prairie remnants in the western part of the state. This moth is limited to prairies, savannas, and sandy open woodlands where its larval food plant grows. It is difficult to detect, and may be more common in the state than the few records indicate. However, less than 1% of Minnesota's original prairie remains, and this continues to diminish. Rapidly increasing development severely threatens the sandy woodland habitats. For these reasons, the phlox moth was listed as a special concern species in Minnesota in 1996.
In the phlox moth, the sexes are similar in size and coloration. Adults are small, with a forewing length (base to apex) of 8-10 mm (0.31-0.39 in.). The forewings are gray-violet with a patch of crimson near the base and a broad crimson band near the margin. There is a prominent fringe of pale tan to gray scales in fresh individuals. The thorax is clothed in a dark violet-gray fur of long hairlike scales. The hind wings, rarely visible in living moths, are a dark charcoal with a pale fringe. Adults are usually observed resting on the inflorescenses of prairie phlox (Phlox pilosa var. fulgida), their wings folded back over their bodies like a tent, where their coloration makes them resemble a recently withered phlox blossom. There is no similar moth in Minnesota.
In Minnesota, the phlox moth has been observed only in native upland prairie habitat. In Wisconsin, most documented occurrences are in sandy savanna or barrens habitats (Wisconsin DNR 2008). The crucial habitat feature is the presence of prairie phlox, the larval food plant.
Biology / Life History
As its name implies, the phlox moth is intimately associated with phlox. The only documented larval food plant in the wild is prairie phlox, although larvae have been successfully reared in captivity on other phlox species. Larvae eat the reproductive parts of phlox plants: early instars (developmental stages) bore into the flower bud and developing ovary, while later instars feed externally on the ripening fruit (seed capsules) (Hardwick 1996).
Conservation / Management
Survey work is needed to determine if the phlox moth is more common in Minnesota than current records indicate. Prairie phlox is typically present in remnant native prairies as far north as Polk County. Survey work is also needed in sandy woodlands and barrens east of the prairie-forest boundary.
Conservation Efforts in Minnesota
The five known occurrences of the phlox moth are within protected sites managed to maintain the native prairie. Three of these sites were recently discovered during the first survey effort directed at this species, which was limited to eight counties in the southwest corner of the state. This suggests that the moth is likely to occur at many other protected and managed prairie remnants in Minnesota. Guidelines for protecting Lepidoptera populations within a fire-management program are employed by most of the major owners of potential phlox moth habitat in Minnesota, and efforts have been made to educate other land managers. Data on the locations of phlox moth colonies are maintained by the Minnesota DNR's Natural Heritage and Nongame Research Program and consulted during the state environmental review process so that projects can be modified to reduce or avoid harm.
References and Additional Information
Hardwick, D. F. 1996. A monograph to the North American Heliothentinae (Lepidoptera: Noctuidae). David F. Hardwick, Ottowa, Ontario. 281 pp.
NatureServe. 2008. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, Virginia.
Swengel, A. B., and S. R. Swengel. 1999. Observations on Schinia indiana and Schinia lucens in the midwestern United States (Lepidoptera: Noctuidae). Holarctic Lepidoptera 6(1):11-21.
Wisconsin Department of Natural Resources [WIDNR]. 2008. Phlox Flower Moth Schinia indiana (Smith).