Although recent research has expanded knowledge of the myriad physiological roles played by crustacean hemocytes, synthesis of this knowledge is impossible at present because of the lack of a coherent, unified classification scheme for these cells. Using the penaeid shrimp, Sicyonia ingentis, as a prototype for the decapod crustaceans, a hemocyte classification system was developed which relates cellular morphology and cytochemistry with three essential functions, clotting, phagocytosis, and encapsulation. The overall goals of this research are to develop a unified hemocyte classification system for the decapods to include taxonomically diverse species, taking into account possible variability in hemocyte morphology, cytochemistry, and function throughout the molt cycle, which is known to affect hemocyte abundance and function. Two experiments are proposed for the coming year. The first, using methods developed for the shrimp, will explore the relationships between hemocyte morphology, cytochemistry, and the physiological functions of clotting, phagocytosis, and exoskeleton hardening, using a macruran, Panulirus interruptus, and a brachyuran, Loxorhynchus grandis. The second experiment will determine whether there are temporal changes related to molting state in the abundance, production, and activity of hemocytes. Using the shrimp, changes in total hemocyte abundance and differential proportions at various points during proecdysis, ecdysis, and post ecdysis will be correlated with the proportions of hemocytes participating in clotting, phagocytosis and hardening of the exoskeleton. Abundance of hemocytes comprising each category will be correlated with their production within the hematopoietic nodules. This information should permit correlation of specific features of decapod hemocytes with their ability to perform specific functions essential to survival of the organisms throughout the molt cycle. The results of this research will broaden our understanding of the self recognition and self defense mechanisms of crabs and shrimp, and, since it will be pursued at an undergraduate institution, it will provide bright and motivated students with the opportunity to gain first hand experience with research.
