Two key hormones, ecdysone and juvenile hormone, control metamorphosis and moulting in insects. Stated simply, the role of juvenile hormone in insect development is to determine the type of moult that is undertaken by the insect. The presence of juvenile hormone maintains juvenile characteristics and prevents development of the adult form (Kumaran, 1990). Very low levels of juvenile hormone are found in the insect immediately preceding a larval to pupal moult, while absence of juvenile hormone in the insect leads to a pupal to adult moult. There are at least six fonts of juvenile hormone that occur alone or in combination across different insect orders and developmental states. Juvenile hormone III is the most commonly detected form across insect orders. However, there is some evidence that in the higher Diptera such as D. melanogaster JHIII is a precursor for an alternative form of the hormone, juvenile hormone III bisepoxide (Richard et al 1989).