K. Hejno

Natural and synthetic materials with insect hormones activity 8. Juvenile activity of the farnesane-type compounds on Galleria Mellonella

Abstract Farnesol, farnesyl ethers, farnesoate esters, and similar compounds act as potent analogues of juvenile hormone on several insect species (1,2,3). In tests on the larvae of Galleria mellonella , however, these chemicals displayed only very slight activities (unpublished observation). Their failure to induce a juvenilizing effect was puzzling since the larvae readily react to tiny amounts of Cecropia juvenile hormone (4,5) which is structurally related to farnesane-type sesquiterpenoids. Being stimulated by the contrast between the high activity of natural juvenile hormone (JH) and the negligible activity of farnesyl ethers and alkyl farnesoates, we started a detail investigation of the relation between the chemical structure and the juvenile hormone activity. This report describes the activity of compounds with the farnesane carbon skeleton but differing in the number of double bonds and the presence of halogen atom(s) or oxirane ring(s) in the molecule. It has been well established that there are great species specific differences in the activity of JH-analogues; e.g. the juvabione and related compounds act on Pyrrchocorids but not on other bugs (6). No attempts have been made, however, to examine whether similar differences do not exist also between successive developmental stages of a single species. Aiming to this goal, we employed in our tests both larvae and pupae of Galleria .