温度对西花蓟马生长发育、 繁殖和种群增长的影响

西花蓟马Frankliniella occidentalis (Pergande)是一种入侵我国的重要害虫， 温度是决定蓟马能否建立稳定种群的最基本因素。为明确温度对西花蓟马种群增长的影响， 本研究在室内观察了西花蓟马在15℃， 20℃， 25℃， 30℃和35℃温度条件下的生长发育、 存活与繁殖能力， 并计算各温度条件下的种群增长参数。结果表明： 在35℃条件下， 西花蓟马不能完成发育， 其他温度条件下西花蓟马从卵孵化至蛹羽化成成虫， 以20℃条件下的存活率最高， 为62.8%。西花蓟马发育速率随温度升高明显加快， 在15℃下， 完成发育需要近30 d； 而在30℃下， 西花蓟马完成发育仅需10 d 左右。西花蓟马成虫寿命随温度的升高而明显缩短， 在15℃下， 平均寿命为36 d， 最长寿命达60 d； 在30℃下， 西花蓟马的平均寿命为10 d。西花蓟马在 15℃， 20℃和25℃条件下的平均繁殖力差异不显著， 分别为37.70， 32.56， 37.80头1龄若虫/雌， 但显著高于30℃条件下的平均繁殖力（9.36头1龄若虫/雌）。西花蓟马的种群增长参数净生殖率(R0)、 内禀增长率(rm)， 在25℃时达最高值， 分别为20.10和0.178 d-1， 而在15℃下分别仅为18.67和0.096 d-1。据此得出， 20~25℃是最适宜西花蓟马生长发育和繁殖温度范围， 温度过高或过低都不利于西花蓟马种群增长。西花蓟马的发育起点温度为7.4℃， 充分完成发育所需的有效积温为208.0日·度。不考虑其他阻碍生长发育因素的情况下， 华南、 华中、 华北和东北地区的年发生代数分别为24~26， 16~18， 13~14和1~4代， 西南地区昆明与丽江分别为13~15和8~10代。

Effects of temperature on development, reproduction and population growth of the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae)

The western flower thrips, Frankliniella occidentalis (Pergande), is an invasive pest in China. Temperature is a key determinant for the stable establishment of thrips population in a new environment. In order to know the effects of temperature on the population growth of the western flower thrips, we investigated the development, survivorship and reproduction of F. occidentalis at different temperatures (15, 20, 25, 30 and 35℃), and calculated the parameters of population increase under different temperature conditions. The results indicated that the survivorship of F. occidentalis from egg-hatch to adult was the highest (62.8%) at 20℃, but no individual developed into adult at 35℃. The development rate increased significantly with rising temperature, the average developmental duration from egg to adult stage was about 30 d at 15℃, while the shortest was about 10 d at 30℃. The adult longevity was evidently shortened with rising temperature, at 15℃ the average lifespan was 36 d, the longest adult longevity even reached more than 60 d, while at 30℃ the shortest was only 10 d. The differences of fecundity (total number of the 1st instar nymphs produced by individual female) were not significant among 15, 20 and 25℃, with the values of 37.70, 32.56 and 37.80, respectively, which were all higher than that of the thrips at 30℃ (9.36 1st instar nymphs produced by individual female). The parameters of population growth ［the intrinsic rate of increase (r_m) and the net reproductive rate (R₀)］ were the highest at 25℃, with the values of 0.178 and 20.10 d^-1, respectively, while those at 15℃ were only 0.096 and 18.67 d^-1, respectively. From these results we concluded that temperature has great effect on the development of F. occidentalis, and the most suitable temperature range for this pest is 20-25℃, during which the intrinsic increase rate is higher. The development threshold temperature of F. occidentalis was estimated to be 7.4℃ and the effective accumulated temperature for development was 208.0 degree days. In South China, Central China, North China and Northeast China, the estimated numbers of generations per year are 24-26, 16-18, 13-14 and 1-4, respectively, without consideration of other factors influencing the development and growth of the thrips. Especially in Kunming and Lijiang, Yunnan in Southwest China, the estimated number of generations per year are 13-15 and 8-10, respectively.