Seed production and propagation of northern bog violet (Viola nephrophylla) for Nokomis fritillary (Speyeria nokomis) butterfly habitat restoration

Abstract

The Nokomis fritillary (Speyeria nokomis Edwards [Lepidoptera: Nymphalidae]) is a North American butterfly with unique dietary and reproduction requirements. The only confirmed food source of the Nokomis fritillary larva is the northern bog violet (Viola nephrophylla Greene [Violaceae]), making seed and plant production of this plant critical to habitat restoration. Fifty mother plants established from seed in spring produced 10,000 seeds by cleistogamy during the summer. Stratification plus soaking in oxygenated water yielded mixed results on germination. Maximum germination (33%) was observed with 60 d stratification on blotter paper. Attempts to produce plants through asexual propagation were unsuccessful. Anecdotal observations suggest that improved seed cleaning and exposure to freeze/thaw cycles may improve seed germination.