This paper explores the engineering contributions of a Web-based simulator of fruit fly, particularly with regards to software and system infrastructure. This simulation system is the result of a multidisciplinary effort in the areas of ecological simulation modelling and software/systems engineering, in order to provide tools to support decision making in biosecurity. We report on the following interesting software and system engineering aspects: catering for a variety of users, scalability issues, response time requirements, a three-tiered development environment, Web-suitable architecture, a flexible data interchange format, a range of cooperating underlying temporal–spatial models, and the need for evaluation in for non-functional aspects such as scalability in execution time and memory requirements.