The insect juvenile hormone family has recently been enlarged by the addition of its 6th member, juvenile hormone III bisepoxide (JHB3) . JHB3 is first discovered as an unknown juvenoid biosynthesized, in vitro, by the adult corpus allatum (CA) of the female black blow fly, Phormia regina (Liu 1985, Liu et al. 1988). A similar substance is produced by the isolated larval ring gland of Drosophila melanogaster; its chemical structure is identified as methyl (2E,6E)-(10R,11S)-6,7;10,11-bisepoxy-3,7, 11-trimethyl-2-dodecenoate or methyl-s, 7;10,11-bisepoxyfarnesoate (Richard et al. 1989a). This substancev is structurally identical to juvenile hormone 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 regina (Richard et al. 1989a,b 1990, Yin et al. submitted). JHB3 also has been found to be a product of either the ring glands or the CA in all the higher dipterans (i.e., cyclorrhaphous flies) studied so far. Its production by the mosquito male accessory gland and the tick synganglion, 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 that the conventional wisdom of thinking that all non-Iepidopterans can produce only JH III is far from reality.
Phormia, Corpus allatum, Diptera, JH bisepoxide, JH biosynthesis
