This award will support collaborative research between Dr. William Murdoch, University of California at Santa Barbara, and three British ecologists: Profs. Roger Nesbit and William Gurney, University of Strathclyde, Glasgow, and Dr. Charles Godfray, Population Biology Center, Imperial College Field Station, Silwood Park. In cooperation with these scientists, Dr. Murdoch will develop and analyze a number of related models, describing the interaction between red scale, a pest insect on citrus, and its controlling parasitoid, Aphytis. Examples of biological control provide the population ecologist with unparalleled opportunities to study the mechanism by which enemies (parasitoids and predators) control host or prey populations. Biological control has provided the impetus for a broad range of parasitoid-host theory. Surprisingly, however, very few population ecologists have done field studies of real biological control systems. Dr. Murdoch has collected extensive sets of experimental field data on red scale/Aphytis interactions, and in collaboration with British colleagues, has also developed several stage-structured models. The proposed collaboration will complete the analysis of existing versions of these models, parameterize and carry out extensive computer investigations of these versions, and develop new versions in response to field results recently obtained by Dr. Murdoch. The project will benefit from the complementary expertise of the U.S. and British collaborators. Profs. Nisbet and Gurney are the foremost experts on the development and analysis of the stage-structured models being used in this project. Dr. Godfray is an expert on the strategic versions of the sex-allocation/host feeding model.
