REFUGE THEORY AND BIOLOGICAL-CONTROL

An important question in ecology is the extent to which populations an d communities are governed by general rules. Recent developments in po pulation dynamics theory have shown that hosts' refuges from their ins ect parasitoids predict parasitoid community richness patterns. Here, the refuge theory is extended to biological control, in which parasito ids are imported for the control of insect pests. Theory predicts, and data confirm, that the success of biological control is inversely rel ated to the proportion of insects protected from parasitoid attack. Re fuges therefore provide a general mechanism for interpreting ecologica l patterns at both the community level (their species diversity) and p opulation level (their dynamics).