在自然界的动物种群中,昆虫的种群是最多的。全世界已知动物150多万种,昆虫就占2/3以上,其中有许多昆虫长期栖息繁衍于森林之中,形成较稳定的森林生态系统。但是,由于自然因素和人为因素的不断影响,往往引起昆虫群落组成的变化和种群数量的消长,以致有的种群得以昌盛,有的种群却逐渐凋落。毫无疑义,弄清森林昆虫区系的演替规律,不仅在害虫防治、益虫利用及植物检疫上具有十分重要的意义,而且对于林业区划,对树种的选育、配置、引进和更新,对森林的营造、间伐和抚育管理等亦有一定的参考价值。建国三十四年来,陕西也和全国一样,在中央林业部的统一部署下,进行过两次大规模的全省性森林昆虫区系调查,并对一些主要害虫进行了较深入的研究,取得一定成 Among the natural animal populations, the insect population is the largest. More than 1.5 million animal species are known in the world, accounting for more than two-thirds of the insects. Many insects multiply in their forests for a long time to form more stable forest ecosystems. However, due to the continuous influence of natural and man-made factors, the composition of insect community often changes and the population growth and decline, so that some populations flourish, while others decline gradually. No doubt, to understand the forest law of succession of insect fauna, not only in pest control, beneficial insects and plant quarantine has a very important significance, but also for forestry zoning, tree breeding, configuration, introduction and update, Forest creation, thinning and tending and management also have some reference value. In the 34 years since the founding of the People’s Republic of China, Shaanxi has, like the whole country, under the unified arrangements of the Central Forestry Department, conducted two large-scale surveys on the province’s forest insects and carried out in-depth studies on some major pests to obtain Certainly