保护地黄瓜截形叶螨种群动态的研究

截形叶螨在保护地黄瓜上的空间格局为聚集分布．分布的基本成分为个体群，聚集强度与叶螨的密度有关，随着密度的上升而下降；截形叶螨在保护地黄瓜上呈指数增长，模型为N1=1．3634e^0.31261(R=0．9174^**)。应用最优分割法将截形叶螨种群动态划分为3个阶段：初建期、发展期和高峰期。在种群初建期，截形叶螨开始迁入，数量较低，以扩散为主，分布不均匀，聚集强度较高；在发展期，截形叶螨种群不断扩散，分布日均匀，聚集强度逐渐下降；在高峰期，截形叶螨种群数量急剧增长到高峰，聚集强度继续下降，此阶段由于黄瓜接近成熟及受害枯萎．截形叶螨因缺少食物而数量急剧下降。

STUDIES ON THE POPULATION DYNAMICS OF Tetranychus truncatus Ehara IN GREENHOUSE

The spatial patterns of Tetranychus truncatus Ehara were aggregated among the cucumber plants in plastic greenhouse. The basic components of aggregation were colonies. The aggregation intensity correlated with the density of the mites and declined with the increase of the mite population density. The mite populaion increased following the exponential nodel:N_t=1.3634e~(0.3126t)(R=0.9174~(**)).Using the division method, the population dynamics was divided into three periods. In the early establishment period, the mites began to occur in the greenhouse and diffuse among the plants. The population density was lower and the aggregation intensity was high during early period. In the developmental period, the mites reproduced and diffused constantly. They tended to distributd evenly and the aggregation intensity decreased gradually. In the fastigium, the plpulation increased sharply to the highest and distrbuted almost all the plants, and the aggregation continued to decrease. Since then, the population declined rapidly due to the wil of cucunber plants caused by the injury.