Date of this Version
Nature Education Knowledge 1(10):2
Predictions of future population size often assume population structures are stable. Are we missing the boat if we ignore the occurrence of unstable or transient dynamics?
Agricultural crops are regularly infested with insect pests whose population size can reach outbreak densities in some years, causing considerable income loss to farmers. In general, the risk of pest outbreaks is highest when insects disperse to crop fields early in the growing season and the population growth rate is high. The population growth rate measures how much the population size (i.e., number of individuals of a species in a defined area) changes per unit time. Suites of natural enemies (predators and parasitoids) prey upon insects and thereby reduce the risk of pest insects causing economically significant damage. The most common tool for farmers to control pest insects is the application of insecticides. However, unnecessary insecticide applications incur costs to purchase and use and may increase future pest problems by killing beneficial insects. Scientists can help farmers avoid unnecessary insecticide applications using mathematical models to predict future pest population sizes. Predicting future population sizes and evaluating what factors are most critical for population growth are also essential to other areas in ecology such as invasive species management and conservation ecology.