The effects of the patterns of within-stage survival and feeding rates on modeling foliage consumption were evaluated with a computer simulation model for the immature stages of Mexican bean beetle,Epilachna varivestisMulsant, on dry beans,Phaseolus vulgarisL. Feeding and survival rates were simulated as linear and nonlinear functions of degree-days. Constant and linear age-specific feeding rates within a developmental stage were found to result in different levels of daily consumption. Different types of survival within a developmental stage also greatly altered the amount of daily and total consumption. More importantly, the interaction between survival and feeding patterns resulted in a difference of up to 40.04% of total stage foliage consumption. These results suggest the importance of incorporating within-stage feeding and survival patterns in insect simulation models.