马尾松毛虫暴发机制分析

马尾松毛虫的暴发过程具有周期性和突发性相结合的特点,不同环境条件下,即不同的发生区,发生类型不一样,常灾区是典型的暴发发生类型,偶灾区和无灾区一般为渐进发生型、扩散发生型和低密度稳定发生型.暴发的原因一方面是马尾松毛虫具备了成为暴发种的遗传特性,另一方面是大面积马尾松纯林的存在.暴发的启动因子为高温干旱或由环境噪音引起的混沌动态,暴发的上升期为正密度相关作用驱使,下降期和潜伏期主要是由松树诱导抗性、严重失叶和天敌所引起的负密度相关的作用.松林和松林节肢动物群落结构的多样性是抑制马尾松毛虫暴发的主要因素.

Approach to Outbreak Mechanism of Dendrolimus punctatus(Lepidoptera: Lasiocampidae)

The outbreak pattern of Masson Pine Caterpillar(MPC),Demdraolimus punctatus,have both periodic and stochastic characteristics.In different environment conditions the outbreak pattern are different.In frequently outbreak area,the pattern is usually eruptive,while in occasionally outbreak and non-outbreak area the pattern are gradient,emigration,or stable at low population density.The outbreak causes in one hand is high fecundity of MPC and more importantly the existence of large-scale pure pine forests.Outbreaks usually initiate by high temperature and drought or chaotic dynamics under the influence of environmental noise.During the increase phase the dynamics are droved by positive density dependent factors while in decline and endemic phase the negative density dependent factors such as induced host resistance and natural enemies play an important role.Vegetation and invertebrate diversity take a main role in the suppression of MPC outbreaks.