JUVENILE HORMONE-III BISEPOXIDE - NEW MEMBER OF THE INSECT JUVENILE-HORMONE FAMILY

The insect juvenile hormone family has recently been enlarged by the a ddition of its 6th member, juvenile hormone III bisepoxide (JHB3). JHB 3 is first discovered as an unknown juvenoid biosynthesized, in vitro, by the adult corpus allatum (CA) of the female black blow fly, Phormi a regina (Liu 1985, Liu et al. 1988). A similar substance is produced by the isolated larval ring gland of Drosophila melanogaster; its chem ical structure is identified as methyl -6,7;10,11-bisepoxy-3,7,11-trim ethyl-2-dodecenoate or methyl-6,7;10, 11-bisepoxyfarnesoate (Richard e t al. 1989a). This substance is structurally identical to juvenile hor mone III, except for the 6,7-epoxy group. Bioassays of synthetic JHB3 demonstrate its biological activities in the regulation of development , metamorphosis and oogenesis in Drosophila melanogaster and Phormia r egina (Richard et al. 1989a,b 1990, Yin et al. submitted). JHB3 also h as been found to be a product of either the ring glands or the CA in a ll the higher dipterans (i.e., cyclorrhaphous flies) studied so far. I ts production by the mosquito male accessory gland and the thick synga glion, in vitro, has also been reported (Borovsky et al. 1994, Roe et al. 1993). The occurrence of JHB3 calls for future research aiming at the discovery of JHB0, JHB1, and JHB2. Its presence also makes clear t hat the conventional wisdom of thinking that all non-lepidopterans can produce only JH III is far from reality.