艾德斯蚊子咬人

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雌性蚊子传播了疟疾和登革热等寄生虫病，而雄性蚊子对我们来说相对无害。但是，雄性蚊子可以被利用是非常致命的 - 至少对自己的物种。

Previously on BugBitten, we discussed a new auto-dissemination technique that employs insecticide-contaminated male mosquitoes to target larvae, and this week we look at a new sterile insect technique (SIT) that also could become an effective vector control.

SIT is a non-insecticidal control method that releases sterile male mosquitoes into endemic areas to mate with wild females and stop them having offspring. SIT has been used since the 1960s, but had limited success until recently because it was difficult to produce sufficient numbers of competitive sterile males. The SIT method has had more success in recent years when transgenic techniques have been used to produce sterile mosquitoes. However, the use of genetically modified insects still needs refinement and there is also the public concern over anything GM, making an alternative SIT method advisable.

这是Whyard和他的同事进来的地方。他们已经发展了非GM方法使用RNAi技术创建无菌男性埃及埃及蚊子and, at the same time, also suppress the development of female mosquitoes.

显示涉及精子发生的靶向基因的五个DSRNA显示出雄性不育，并将后代降低超过75％。为了产生无菌雄性，将蚊子幼虫浸泡在包含DSRNA的溶液中或喂养的溶液中e.coli表达发夹dsRNA的细菌。两种技术都产生了多达92％的无菌雄性。为了确保仅产生雄性，幼虫也可以馈送或浸泡在靶向doublesex基因的dsRNA中（从而阻止了女性的发育）。

为了测试他们的RNAI诱发的无菌雄性是否可以真正抑制蚊子的种群，Whyard和他的同事将无菌雄性（以不同的密度）与未处理的雄性混合在一起，并将其置于有野生女性的笼子里。结果表明，当种群被25％的无菌雄性种子时，蚊子种群显着下降，但是当无菌雄性蚊子的比例上升到50％时，后代下降了50％。此外，当无菌雄性蚊子的比例为75％时，人口抑制在95％至100％之间。

Whyard及其同事开发的方法是生产有竞争力的无菌男性蚊子的一种有效而优雅的方法，该蚊子解决了先前SIT方法的缺点，例如社会对GM技术的厌恶。这也意味着我们可以避免将化学杀虫剂释放到环境中。但是，生产DSRNA很昂贵 - Whyard和他的合着者承认这是目前大规模矢量控制方法的昂贵的。但是，如果将来通过技术进步来降低DSRNA的产生成本，那么它可能会成为一种可行的向量控制方法。