白蜡虫自然种群年龄特征生命表及主要死亡因素分析

Age-Specific Life Table of Chinese White Wax Scale(Ericerus pela) Natural Population and Analysis of Death key Factors

白蜡虫自然种群生命表研究表明：白蜡虫繁殖力强,怀卵量为8000～12000粒.♀-1,死亡率高,世代死亡率高达99%以上,高繁殖力和高死亡率是白蜡虫种的特征,白蜡虫以高繁殖力补偿高死亡率,使种群延续。白蜡虫阶段死亡差异较大,卵期死亡率为9.58%,1龄若虫死亡率为85.25%,死亡高峰期在新孵1龄若虫寻找寄主植物叶片上定叶的过程中;2龄若虫的死亡率为45.50%,死亡高峰期在2龄若虫初期从叶片上转移到枝条上定杆的过程中;成虫期死亡率94.64%。1龄若虫死亡率最高,占总死亡率的70%左右;2龄若虫死亡率占总死亡率的10%～15%;成虫期死亡率占总死亡率的2%～5%。平均种群增长趋势指数为32。气象条件和天敌是影响白蜡虫种群数量变动的主要因素。

Ericerus pela is an important resource insect with great economic value. The white wax excreted by this insect is an important chemical raw materials which is widely applied in some of chemical industries. The 6 generation age-specific life table showed that the fecundity of Ericerus pela was very high, with 8 000 ~ 12 000 egg＂ ~ - 1 . However, its death rate was high, female mortality was about 99 % and male mortality was more than 96 %. The high fecundity and the high death were unique characters of E. pela natural population. The mortality at egg average was 9.58 %, and the mortality of the Ist instar nymph was 85.25 %, about 70 % of total mortality in a generation. About 80 % of new hatched larvae died during the period when these nymph crawl and seek suitable leaf of host tree to live on. The mortality of the 2＂a instar nymph was 45.50%, 10% ~ 15% of a generation mortality, and death peak occured in the period when they moved from leave to branch to live on. The mortality at adult stage was average 94.64 %, which was 2 % ~ 5 % of total mortality. In one generation, average index of population increase trend were 32. Weather and natural enemy are were major death factors which affected natural population size. Before E. pela live on branch, weather was the key factor of nymph death. Most of nymph were blew away by wind or washed out by rain, because the nymph had poor defense capability. After the insect lived on branch, wax excreted by 2~a instar male larvae covered on themselves body, female body gradually became big and keratinized, so that their protective capability became stronger. After then natural enemy, such as parasite wasps and preyed beetles, became the main death factors.