Observations on the seasonal biology and apparen tmigration of argynnis (Speyeria) coronis (Nymphalidae) in Central Washington

Abstract

Opportunistic observations on the seasonal biology of Argynnis coronis in central Washington obtained over 40 y ears, suggest that the ecology of this species is characterized by well defined seasonal population movements between low and high elevations. Unfed first instar larvae diapause and overwinter in lithosol shrub-steppe areas immediately east of the Cascade Mountains feeding and developing on sagebrush violets (Viola trinervata) during March-May. Males eclose 7-14 days before females in midlate May. After mating, females delay egg development and migrate 50-100 km westward reaching high elevations in the Cascades by late June-early July. Most males die in the shrub-steppe but a few migrate with the females. Female-dominated populations oversummer at 2,000-2,500m and are active feeding on flowers but remain non-reproductive. Ovaries develop in early August and females begin an eastward downslope movement returning to shrub-steppe areas by early September. Opposition on soil, stones, rocks and ground level woody plants where violets grow in spring, occurs during September and early October.