TEMPERATURE-CHANGE AND COMPLEX DYNAMICS

Density-dependent factors, such as population growth rate and migratio n, influence dynamic behaviour in ecological models. Temperature, an a biotic and density-independent factor, is also an important determinan t of insect population growth. We investigated the endogenous dynamics of a density-dependent response-surface model that included temperatu re, based on time series for two aphid species. We investigated the ef fects of temperature and random noise on the model dynamics. In most c ases, an increase in temperature resulted in a higher predicted equili brium density; it could induce complex dynamics. Noise at the level of the natural variation in temperature resulted in extinctions in some models. Our results from these models indicate that aphid populations might become more abundant, and less stable in some circumstances, if there is climate warming.