低温胁迫对荔枝蒂蛀虫幼虫存活和发育的影响

Effects of low-temperature stress on the survival and development of the litchi fruit borer

荔枝蒂蛀虫Conopomorpha sinensis是为害荔枝龙眼的重要害虫,以幼虫越冬。了解其幼虫经历低温胁迫后的存活率和发育历期有助于预测其种群数量动态。本研究于室内测定荔枝蒂蛀虫幼虫在不同低温条件下(5、10℃和15℃)处理1、3、5、7、10 d和15 d的存活率和发育历期及其对蛹和成虫发育的影响。结果表明,幼虫在5℃下处理1 d、3 d其存活率分别为48.54%和35.79%,分别为对照的1/2、1/3;10℃下处理7 d存活率为41.75%,降为对照的1/2。幼虫在5℃下处理3 d后蛹的存活率为45.95%,降至对照的1/2;10℃和15℃处理15 d降为31.11%和30.61%,约为对照的30%左右。幼虫历期在5℃处理3 d(8.14 d)、10℃处理5 d(8.43 d)和15℃处理7 d(9.32 d)时均可达对照的2倍。3种低温条件均造成荔枝蒂蛀虫蛹历期和成虫寿命缩短。由此可见,冬春季5~15℃的低温会引起荔枝蒂蛀虫幼虫和蛹存活率显著降低以及不同虫态历期的异常变化,可导致荔枝蒂蛀虫的虫源减少。

The litchi fruit borer,Conopomorpha sinensis Bradly,is an important pest of litchi and longan.It overwinters as larvae.Understanding the survival rate and developmental period of the larvae after low-temperature stress would help to predict the population dynamics.In this study the survival rates and developmental durations of C.sinensis larvae were determined by treating the larvae at 5,10℃and 15℃in the laboratory for 1,3,5,7,10 d and 15 d,and the effect of the treatments on the development of pupae and adults was also investigated.The survival rates of larvae were 48.54%and 35.79%,when larvae exposed to 5℃for one day and three days,respectively,which were only 1/2 and 1/3 of that of the control group;and the survival rate waS41.75%(1/2 of that of the control group)when the larvae were treated at 10℃for seven days.The survival rate of pupae dropped to 45.95%(1/2 of that of the control group)when the larvae was treated at 5℃for three days,and it dropped to 31.11%和30.61%(about 30%of that of the control group)when the larvae were treated at 10℃or 15℃for 15 d.The larval durations were 8.14,8.43 d and 9.32 d,when larvae were treated at 5℃for three days,10℃for five days and 15℃for seven days,respectively,which were twice as much as that of the control group.Pupal duration and adult lifespan of C.sinensis were all shortened after treatment at 5,10℃and 15℃.It indicated that,in winter and spring when the temperature is in the range of 5-15℃,the survival rates of C.sinensis larvae and pupae will be significantly reduced,leading to abnormal development of insect and a decrease of the C.sinensis populations size.