Abstract：Many mathematical models have been used to study population dynamics of host-parasitoid systems. Some model predictions have been qualitatively proved by empirical data. However, majority of these models assume fixed times for development stages of insects. In reality, it is not the case for most insects. In this talk, I will talk about the effects of distributed development time on population dynamics of host-parasitoid systems, and fitting our model to the data from a specific host-parasitoid system in our lab.