高温影响蚊子的繁殖

南方的朋友或许会发现，今年夏天的蚊子少了很多。越挠越痒的蚊子包，惹人心烦的嗡嗡声出现的频率都不及往年。早早准备好的蚊香和花露水似乎少了很多用武之地。有人不免发出疑惑：难道......连蚊子都要被热死了？

 

没错，但不是蚊子本蚊被热死，而是蚊子的孩子被热死了！

 

Have you noticed fewer itchy, red bumps on your skin this summer? It's probably due to the hot, dry weather this summer.

 

蚊子是怎么被“热死”的

 

蚊子的繁殖也得靠天时地利，而高温导致池沼、水沟等静水大量干涸，蚊子失去了产卵圣地，被纷纷“扼杀在摇篮里”。

 

The right amount of rain at the right time is needed for mosquitoes to breed because it lays eggs on the surface of stagnant¹ water.

 

即使成功“苟活”下来，在高温环境下长大的蚊子，虽然发育速度更快，但成虫体型更小，繁殖能力也更低，难以“传宗接代”。

Individuals reared at higher temperatures may develop more rapidly compared to lower temperatures, but adults tend to be smaller with reduced fitness given that size is often positively² related to fecundity³.

 

此外，高温还会降低成年蚊子的活跃程度。就像人们知道躲进空调房，蚊子也知道飞去阴凉处，不会在烈日炎炎的时候出来自讨苦吃。

As temperatures climb higher, mosquito activity can decline. Mosquitoes will bite less when it becomes excessively hot.

 

先别急着庆幸

 

要庆祝蚊子灭绝还为时过早。顽强的害虫不会坐以待毙，既然南方太热，那就去北方避暑！

 

许多蚊子原本生活在东南亚国家，经过海上贸易传到我国，主要在广东、广西和云南活动。近年来，高温席卷南方，蚊子也来到了北方“避暑”。

 

危害性更强的是，虽然高温不利于蚊子生存，却有利于蚊子携带的病毒传播。只要一息尚存，高温之后的凉爽期，很可能就成了蚊子传播疾病的最佳时机。

Higher temperatures also make any diseases they carry more active and hence more transmissible. So when mosquitoes are around, a cool spell following very hot temperatures could be ripe for mosquito borne diseases, as highly infectious mosquitoes increase their biting activity.

 

主要有三类蚊子会传播疾病：库蚊（Culex）、伊蚊（Aedes）和按蚊（Anopheles），传播的疾病包括疟疾（malaria）、丝虫病（filariasis）、和登革热（dengue）等。

 

高温对其他昆虫的影响

 

蚊子锐减可谓太快人心，但如果是对人类有益的昆虫受到影响，那就另当别论了。

 

最近连月高温，许多欧洲国家出现蜜蜂连续死亡，而且死去的大部分是雄蜂。雄蜂对温度十分敏感，高温的压力下，雄蜂的自然反应是射精，然后死去。

Beekeepers in European reported unusual deaths of honeybee queens, drones and small colonies. Drones, which are the reproductive males, spontaneously ejaculate when they die from stress.

 

就算雄蜂熬过了高温，生育能力也会受损。等到热浪过去，蜂后与雄蜂的交配机会减少，可能会导致整个蜂群的崩溃。依赖蜜蜂授粉的植物也会遭殃，其中有不少是人类赖以生存的农作物。

Worryingly, male fertility likely begins to decline well before the drones die. This means that after a heat wave, new queens — the reproductive females — will have fewer opportunities to mate. Colonies headed by poorly mated queens are more likely to collapse⁴, and this could pose problems for farmers who rely on honeybees to pollinate their crops.

 

说到底，蚊子变少，也是大自然对我们敲响的警钟。如果放任气候变暖、环境恶化，终有一天会波及人类自身。

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