温度对扶桑绵粉蚧生长发育的影响

Effects of temperature on the development and reproduction of Phenacoccus solenopsis(Hemiptera:Pseudococcidae)

【目的】扶桑绵粉蚧Phenacoccus solenopsis Tinsley是近年在我国新发现的一种重要外来人侵害虫，对我国棉花生产具有潜在的巨大威胁。本研究以棉花作为寄主，探索恒温及变温条件对扶桑绵粉蚧生长发育的影响。【方法】在光周期为12L：12D，RH70％±5％，在系列恒温及变温（温度波动范围为±1℃）条件下，用棉花饲养扶桑绵粉蚧，观察和分析了不同温度下各龄虫态的发育历期、发育速率、存活率和繁殖力及发育起点温度、有效积温、最适发育温度、极限高温等。【结果】在恒温17-32％范围内，扶桑绵粉蚧各虫态的发育历期随温度升高而逐渐缩短，当温度达到27℃时发育速率值增幅最大，其中在恒温22—32℃范围内，该虫具有较高的生长发育速率和存活率，且繁殖能力较强，而在恒温37％条件下，该虫不能完成整个生活史而死亡。在循环变温条件（25—40℃）下，该虫表现出更好的适应性：发育历期更短，速率更快，存活率更高，繁殖力也达到了恒温条件下的平均水平。雌雄虫的发育起点温度分别为9．0℃和8．1℃，而达到成虫时所需有效积温分别为322．6日度和344．8日度。通过拟合发育速率与温度之间的非线性回归关系求出雌雄虫最适发育温度分别为30．5℃和29．9℃，而极限高温分别为36．6℃和35．8℃。【结论】扶桑绵粉蚧适温范围广泛，特别是在变温条件下的适应性非常强。这些结果为预测扶桑绵粉蚧在我国主要棉区的分布提供了依据。

[ Aim ] The solenopsis mealybug, Phenacoccus solenopsis Tinsley （ Hemiptera ： Pseudococcidae）, is an important alien invasive pest recorded in China in the past several years and has a potential threat to cotton. In this study, the effects of constant and fluctuating temperatures on the growth and development of P. solenopsis on cotton was studied. [ Methods ] Under laboratory conditions （photoperiod 12L： 12D, RH 70% ± 5% ）, the developmental duration, developmental rate, survival and fecundity were investigated under a series of temperatures, and the effective accumulated temperature, developmental threshold temperature and optimal development temperature were analyzed. [ Results ] The results showed that the temperature had significant effect on the development of P. solenopsis. Within the constant temperature ranging from 17 to 32℃, the developmental duration of each stage of P. solenopsis shortened as the temperature rose gradually, and the developmental rate showed a significant positive correlation with temperature. The mealybug had higher developmental rate, survival rate and fecundity during the constant temperatures of 22 - 32℃. However, under the constant temperature of 37℃, the development was suppressed obviously and the mealybug died before completing a whole life span. In the fluctuating circumstance （25 -40℃ ）, P. solenopsis showed a better acclimatization, and had shorter developmental duration, higher survival rate and faster developmental rate. The minimum temperaturethresholds （ Tmin） of females and males were 9.0 and 8. 1 ℃, respectively. The effective accumulated- temperatures （K） of females and males were 322.6 degree-days and 344.8 degree-days, respectively. By analyzing the nonlinear regression relationships of the developmental rate and temperature, we calculated the optimal temperatures （ Topt ） of females and males （30.5 and 29.95 ℃, respectively）, and the maximum temperature thresholds （ Tmax ） of females and males （36.6 and 35.8℃, respectively）. [ Conclusion] P. solenopsis has a wide range of adaptive temperature and can adapt to high temperature threshold under the fluctuating temperatures. These results will be helpful for predicting the distribution of this pest in the cotton regions in China.