Simulation of the dynamics of a microsporidian pathogen of mosquitoes

A biological system involving a microsporidian pathogen (Amblyospora dyxenoides) and two obligate hosts, a mosquito (Culex annulirostris) and a copepod (Mesocyclops spp.) is described. Due to the complexity of the infection cycle of the pathogen, its ability to cause benign infections, and the requirement of multiple host species to complete a life cycle, heuristic evaluation of the dynamics of this system was not adequate to evaluate proposed management strategies. Therefore, in order to assess the effects of differing environmental conditions and potential control strategies used to reduce mosquito populations, a detailed mechanistic simulation model was developed and evaluated using the Hierarchical Environment for Research Modeling of Ecological Systems (HERMES). HERMES is a hierarchical, object-oriented modeling system that facilitates interactive model construction and evaluation. We discuss the model structure, parameter estimation, sensitivity analysis, and critical processes in model verification, validation and evaluation. Comparisons of model results with actual field data reveal that the model reasonably mimicked natural mosquito and pathogen dynamics, allowing it to be used as a tool for evaluating proposed management strategies. Example augmentation releases of the biological control agent were simulated and results are discussed in respect to the C. annulirostris and A. dyxenoides life system and to other mosquito and pathogen life systems that may be considered for biological control manipulation in the future.