高温处理不同龄期埃及伊蚊对其发育的影响

Development effects of Aedes aegypti treated with high temperature water in different larval stages

目的研究水体高温处理不同阶段幼虫后对埃及伊蚊成虫体型、体重和性别比例的影响,探究水体高温对埃及伊蚊这些特征产生影响的关键龄期。方法将不同龄期埃及伊蚊(卵期、1～4龄幼虫)置于36℃水浴中,使埃及伊蚊在水浴锅中度过一个龄期后,移至标准条件下〔温度(25±1)℃,湿度(75±5)%〕常规饲养,羽化为成虫后记录雌雄蚊数量,60℃烤箱中干燥15min测量翅长及体重;同时将同批埃及伊蚊(分别按卵、1～4龄幼虫)置于饲养室常规饲养得到标准值。结果高温作用2～4龄幼虫,其长成的雌蚊翅长明显小于正常值;2龄和4龄幼虫受高温作用后发育的雌蚊体重下降,而卵期、1龄和3龄体重下降不明显;3龄和4龄受高温作用后发育的成虫中雌蚊比例升高,雄∶雌分别为0.88和0.95,2龄幼虫则情况相反,雄∶雌=2.43∶1。结论埃及伊蚊不同阶段受高温作用的影响不同,卵期和1龄幼虫受高温影响较小,2～4龄受高温影响较大,说明2龄雌性埃及伊蚊是发育的关键阶段,而3龄雄性埃及伊蚊是发育的关键阶段。

Objective To investigate the effects of high temperature water treatment in different larval stages on the body size, body weight, and sex ratio of adult Aedes aegypti and to determine the critical stages when high water temperature exerts significant effects on the above indices. Methods Ae. aegypti larvae of different instars （including egg stage and the first to fourth instars） were divided into experimental group and control group. The larvae in experimental group were kept in a water bath （36 ℃） till they developed to the next instar, and then the living larvae were moved to the insectariums with normal condition [temperature, （25 ± 1）℃ ; humidity, （75 ± 5）% ] and reared conventionally. After eclosion, the numbers of female and male mosquitoes were recorded, and the wing length and body weight were measured after they were dried in an oven （60 ℃） for 15 min. The larvae in control group were reared conventionally in the insectariums to get the standard values. Results For Ae. aegypti larvae of the second to fourth instars in experimental group, their female adults had wing lengths significantly lower than the standard value. For Ae. aegypti larvae of the second and fourth instars in experimental group, their female adults had decreased body weights, but the decrease was not significant for the larvae in the egg stage, first instar, and third instar. For Ae. aegypti larvae of the third and fourth instars, their adults had male/female ratios of 0.88∶1 and 0.95∶1, while the ratio was 2.43∶1 for the larvae of the second instar. Conclusion The effects of high temperature water treatment on Ae. aegypti vary depending on the larval stage; the larvae in the egg stage and first instar are less sensitive to the high water temperature than those in the second to fourth instars. The second instar is a critical stage for the development of female Ae. aegypti, and the third instar is a critical stage for the development of male Ae. aegypti.