Complex Dynamics of Mason Pine Caterpillar, Dendrolimus punctatus (Lepidoptera: Lasiocampidae) Populations

We detected the existence of chaotic behavior in mason pine caterpillar (MPC) populations using response surface methods. We found that a small noise made the local Lyapunov Exponents fluctuated above zero, though all estimated Global Lyapunov Exponents were negative and the local Lyapunov Exponents were fluctuated below zero without the noise. This implies that noise could play an important role on the population dynamics and causes in the system. The simulation result showed the damped oscillation or limited cycle. The population dynamics of year-to-year time series damped quickly to the equilibrium while that of generation to generation time series ran relatively slowly to the equilibrium. The temporal pattern of MPC may vary at different temporal and spatial scales. Population dynamics are more relatively irregular and erratic at smaller scales. For the management of MPC most important prediction is at the beginning of the outbreak. Because of possible chaotic dynamics and first order density dependent, continuous monitoring is needed. The prediction for the next generation should be most reliable.