Neuropeptides as regulators of sesquiterpenoid biosynthesis in arthropods

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Juvenile hormone (JH) is the primary regulator of both the change in body form from larva to adult (metamorphosis) and the production of eggs (reproduction) in most insect species. JH must be present at appropriate times to stimulate the retention of larval characters or the growth of eggs. In its absence, these processes do not occur. Therefore the presence of JH at inappropriate times will disrupt the normal functioning of the insect. My laboratory has focused on the natural compounds that turn JH production on and off in pest species including cockroaches, moths and flies, with our major emphasis on the compounds responsible for turning JH production off. We have discovered a family of peptides (short chains of amino acids) termed allatostatins that are able to inhibit the production of JH. Some of our recent work has been directed to the development of mimics of these peptides that are resistant to breakdown and able to disrupt egg production. To this end, we have also been searching for additional allatostatin regulators of JH production in other pest species such as flies, since at present our knowledge of such compounds is largely confined to cockroaches. There are many related allatostatins in cockroaches but we know that these differ from those in other pest species such as moths and flies. This implies that allatostatins are highly specific, acting only on a narrow range of insects and it may be possible to exploit this specificity, by tailoring specific peptide mimics to act only on specific species. Our work has also focused on the receptors for allatostatins, the cellular keys responsible for the translation of the allatostatin signal since these molecules must be present in the insect's tissues to permit them to respond to the allatostatins. Expression of the receptors may permit the agrochemical industry to search for additional compounds that suppress JH production. We are also studying the JH-related compounds in the crustaceans, including lobster, shrimp and crab, with a view to identifying the regulators of crustacean reproduction and the peptides controlling their production. Such information may prove valuable to commercial aquaculture of lobster crab and shrimp, through the enhancement of growth and reproduction.