Multiple-cohort approach for simulating development of insect populations under variable temperatures

This paper presents a rate-summation approach for modeling the development times of individuals in an insect population held under variable temperatures. The approach integrates a mechanistic poikilotherm rate function and a Weibull distribution function into a simulation model. The rate function determines the median rate of insect development per day at a given temperature, while the distribution function determines the fraction of cohort development at a given accumulated rate. When combined, the rates are accumulated under variable (field) temperatures, and become the independent variable of the distribution function for predicting the cumulative proportion of cohort development through time. Although the computer code relies on specific mathematical equations for describing development rates and the distribution of development times, the same modeling concepts are applicable using other appropriate equations.