OBSERVATIONS OF INCISALIA-IRUS (LEPIDOPTERA, LYCAENIDAE) IN CENTRAL WISCONSIN 1988-95

In surveys conducted during 1988-95, 164 individuals of the frosted el fin (Incisalia irus) were found, 139 of them during formal transects t hat totaled 92.9 hr and 179.4 km of survey effort during the frosted e lfin flight period. Individuals were observed between 10 May and 14 Ju ne, with maximum night spans in a single year of 27-31 days. Peak flig ht occurred just before or at the beginning of peak flowering of the l arval host, wild lupine (Lupinus perennis), and the first spring adult s of Karner blue (Lycaeides melissa samuelis), also monophagous as lar vae on wild lupine. Fourteen individuals exhibited oviposition behavio r on young stalks of green lupine newer buds. 94% of individuals occur red in savannas, nearly evenly split between open (10-24% canopy) and closed (25-49% canopy) ones. Relative lupine abundance at both the mic rosite and landscape scales appeared more important as a habitat facto r than actual size of the particular lupine patch occupied. Both long- term lack: of site management and too frequent/intense management (for estry, rotational fire) appeared unfavorable. Recreational trailsides, areas burned by wildfire >4 years ago, and rights-of-way mowed annual ly or less often were favorable habitat. All frosted elfin sites also supported Karner blues, but within these sites, correlation of frosted elfin abundance with that of Karner blues was rather weak, indicating a fair degree of niche segregation between these two species.