A dynamic life table model of Psorophora columbiae in the southern Louisiana rice agroecosystem with supporting hydrologic submodel. Part 2. Model validation and population dynamics.

In an earlier paper, the development of 2 simulation models designed to describe the interaction between key elements of the rice agroecosystem and the population dynamics of Psorophora columbiae were presented (Focks et al. 1988a). The objective of the work reported herein was to validate these models with field data. The first model (WaterMod) predicts soil hydrology conditions as a function of weather, agricultural practices, and soil characteristics for a variety of habitats found within the rice agroecosystem which are utilized by Ps. columbiae. Using a continuous series of hydrologic data collected in southwestern Louisiana during 1984 and 1985, WaterMod was demonstrated capable of adequately predicting runoff rates and the temporal timing of soil moisture and surface water. The second model (PcSim) simulates the population dynamics of Ps. columbiae based upon a host of variables including the output from WaterMod. This model was validated by comparisons made with density estimates from the literature on the temporal and spatial distribution of various life stages and by correspondence with light trap data gathered during the same time and location as the hydrologic data. PcSim was seen to respond appropriately to host animal densities and unusual meterological events occurring during 1984 and 1985 in southern Louisiana. A discussion is presented of the interaction between agricultural practices and certain key factors of the life history strategy of Ps. columbiae which permit the unusually successful exploitation of the rice agroecosystem by this species. A subsequent paper will use these models to evaluate current and proposed IPM strategies for this mosquito (Focks et al. 1988b).