In aquatic ecosystems, copepods are the most numerically dominant organisms, are ecologically significant, and are a key link in predator/prey trophic system. The terrestrial counterparts to copepods are insects and copepods have often been called the 'insects of the sea'. Extensive information exists on physiological pathways in insects, but little is known about copepod physiology. The central hypothesis to be tested in this proposal is that based on the knowledge that copepods and insects share similar life history strategies; it is likely that the controlling mechanism, that is the neurohormones and neuropeptides, also may be similar among these two taxa. In this study immunoreactivity of the 'insect neuropeptide' family, the FXPRLamides, will be tested in juvenile and adult stages of a freshwater copepod (Cyclops sp.), an estuarine copepod (Acartia sp.) and the commercial white shrimp (Litopenaeus setiferus). This neuropeptide family is a well-characterized group, which is important to producing neuropeptides controlling pheromone production, melanization, myotropic activity, pupariation and diapause in insects and may expected to have multiple effects in copepods as well. Preliminary data suggest that a pheromone synthesizing hormone is expressed in insects, copepods, ants, honeybees and a burrowing shrimp. It is important to determine if aquatic crustacea express the same neuropeptides as insects because antagonists to PBAN (pheromone biosynthesis activating neuropeptide), one of the neuropeptides of the FXPRLamide family, are presently being developed to alter or inhibit the development of insect pests. If insect neuropeptides have the potential of effecting aquatic crustacean population, then the use of insect neuropeptides for insect control has the potential of becoming a serious environmental problem, as chemicals sprayed for insect pest controls can end up in aquatic ecosystems. This project will provide an important first step in determining the presence and level of activity of these important neuropeptides in various life history stages of aquatic crustaceans and whether or not antagonists against insect neuropeptides may affect their development and survival.
