A logistic model simulating environmental changes associated with the growth of populations of rice weevils, Sitophilus oryzae, reared in small cells of wheat.
A logistic model is presented which simulates population growth and concomitant environmental changes when Sitophilus oryzae (L.) is reared on wheat. Parameters quantifying the influences of temperatures and grain moisture content on rates of development, survival and oviposition were determined experimentally. Published data were used to describe the influence of population density on rates of oviposition, while the model also described the distribution of eggs among grains and the depletion of oviposition sites. Published data on age-specific rates of respiration and an energy budget for S. oryzae were used in metabolic modules simulating respiration, feeding and egestion. With the model, it is possible to predict experimentally observed changes in numbers of live adults, moisture content of the grain and the weights of frass produced by populations of S. oryzae reared in small cells of wheat. Afterwards, the model was used in a series of computer experiments to predict the benefits associated with cooling and drying grain and the use of air-tight storage.