叶螨天敌塔六点蓟马生物学特性的研究

【目的】研究了在不同温度下塔六点蓟马Scolothrips takahashii Prisener的生物学参数以及温度对雌虫日产卵动态的影响。【方法】本研究通过在18、22、26、30、34℃5个恒温条件下用二斑叶螨Tetranychus urticae Koch卵对塔六点蓟马单头饲养,明确了不同温度下塔六点蓟马试验种群的生物学特性。【结果】观测表明:在18~34℃范围内,塔六点蓟马的发育随着温度的升高而逐渐加快,在18℃下需要1个月左右,而在34℃下完成1个世代仅需7.8 d;其发育起点温度和有效积温分别为12.4℃和171.0日·度。在18~34℃之间,塔六点蓟马成虫日均食螨卵量随温度升高而上升,在34℃条件下,单雌每日捕食螨卵量达到105粒左右,而若虫期对二斑叶螨卵的总取食量随温度变化不大。此外,塔六点蓟马的子代雌雄性比随温度升高有依次降低的趋势。【结论】根据室内观察结果认为塔六点蓟马是喜温昆虫,据此可以解释早春低温导致天敌塔六点蓟马种群上升缓慢,而6月份气温升高后田间密度迅速上升成为控制叶螨的优势天敌。

Biological characteristics ofScolothrips takahashii Prisener,a natural enemy of mites

Objectives] To investigate the biological parameters of the six spotted thrip Scolothrips takahashiiPrisener at different temperatures, and the effect of temperature on female fecundity.[Methods]The biological characteristics of the six spotted thrip, fed on the eggs of the two-spotted spider mite, were observed at 18, 22, 26, 30, and 34℃, respectively.[Results] The developmental durationof one generation at 18℃ was about one month compared to about 7.8 d at 34℃.The developmental zero and effective accumulated temperatures were 12.4℃ and 171.0 degree days, respectively. The number of mite eggs preyed on by adult six spotted thrips increased with temperature from 18℃ to 34℃. A single female six spotted thrip could consume about 105 mite eggs, however, the number of mite eggs preyed on by thrip larvae was not much affected by temperature. The sex ratio of the six spotted thrip decreased with increasing temperature.[Conclusion] It seems that the six spotted thrip is an insect suited to a high temperature environment. This may explain why six spotted thrip numbers are relatively low in spring but increase suddenly after June making them the dominant natural enemy of mites.