Study on Population Dynamics of Neodiprion xiangyunensis

Studies in 1992～1995 show that the key factor influencing the population dynamics of Neodiprion xiangyunensis is its mortality in pupal stage,i.e.the function of natural enemies. The larvae can give off a substance called “altruism hormone” to prevent themselves from preying by predators,so there is scarcely any influence of predation on its population. The main factor influence the motality of larvae is temperature. Usually the higher the altitude,the higher the mortality,but when at the same altitude,the motality in sunny orientation is greater than that in shady orientation. Due to its feeding habits and high resistance to the natural enemies,the pest can cause great damages within several years once occurred.