SPRUCE CONE AXIS MIDGE, DASINEURA RACHIPHAGA TRIPP (DIPTERA: CECIDOMYIIDAE), IN CONES OF BLACK SPRUCE, PICEA MARIANA (MILL.) B.S.P.

Abstract

AbstractThe development of spruce cone axis midge, Dasineura rachiphaga Tripp, and its parasitoids, Platygaster lucida Fouts and Torymus sp., was studied in relation to the availability and development stage of black spruce, Picea mariana (Mill.) B.S.P., cones.Spruce cone axis midge inhabiting black spruce cones appeared to undergo an extended diapause. This phenomenon probably was related to the production of cones. Platygaster lucida also appeared to undergo extended diapause and the proportion of P. lucida extending their diapause paralleled that of spruce cone axis midge which suggested a close dependance to their host.Spruce cone axis midge, P. lucida, and Torymus sp. emerged from mature cones about the same time and were closely synchronized with the availability of black spruce flowers.External morphological characters of the spruce cone axis midge that separate the two sexes in the pupal stage were described.