INTERACTIONS OF THE AMBROSIA BEETLE, XYLEBORUS DISPAR (COLEOPTERA: SCOLYTIDAE), WITH ITS SYMBIOTIC FUNGUS AMBROSIELLA HARTIGII (FUNGI IMPERFECTI)

Abstract
Two bioassays were used to study the effects of the various life stages of a Temperate Zone ambrosia beetle, Xyleborus dispar (F.) (Coleoptera: Scolytidae), on the induction of the ambrosial form of its symbiotic fungus, Ambrosiella hartigii Batra (Fungi Imperfecti).Postdiapause adults and pupae of X. dispar cause a change from the mycelial to the ambrosial form of A. hartigii in culture.Larvae feed on the mycelial form in vitro, but ambrosia is required by larvae to develop and pupate. One of the main factors inducing the ambrosial form of A. hartigii is probably a secretory product of X. dispar.