蚊子为啥只咬你？

世界上有超过3000种不同类别的蚊子。

Yet, perhaps surprisingly, only a fraction of them actually feed on human beings - and, even when they do, they discriminate when choosing who's their next meal.

或许会令你感到惊讶的是，其中只有很少一部分会吸人血。而且，即使是那些会吸人血的蚊子，在选择目标时也会挑食。

Some people end up covered in bites, while others escape with only a nibble or two. So why does this happen? And what factors might influence the mosquito’s choice?

有些人浑身瘙痒，另一些人身上却只有一两个包。那么为什么会这样呢?哪些因素会影响蚊子的口味呢?

Here, as detailed in The Conversation, Richard Halfpenny, a lecturer in biological sciences at Staffordshire University, explains what makes us worth biting.

来自斯塔福德郡大学的生物科学讲师Richard Halfpenny为我们揭晓了答案。

The human skin’s microbiota

人体皮肤上的微生物群

The best evidence for what motivates a mosquito’s choice between different people is the variation in our skin microbiota.

蚊子出于什么动机才会不同人群中做出选择呢?最佳答案为：我们皮肤上微生物群的变化。

We have an estimated 1m bacteria per square cm of skin, often comprising hundreds of species.

据估计，人体每平方厘米皮肤上拥有100万个细菌，且通常包括数百个种类。

The odour this emits from our pores and hair follicles is the critical factor in telling mosquitoes how tasty we’d be.

而从毛孔与毛囊中所散发的气味，是告诉蚊子我们有多么美味的关键因素。

In other words, mosquitoes don't select somebody for their inner biology, but rather for the micro-organisms that live on their skin.

换句话说，蚊子的口味其实并不会取决于人体内部，而是取决于生活在我们皮肤上的微生物。

The composition of our skin microbiota mostly depends on our environment – what we eat and where we live.

我们的皮肤上微生物群的成分主要取决于我们的环境：我们吃什么与我们住在哪里。

Everything we touch, eat, drink and wash with has the potential to introduce new microbes, but genetic variation is also thought to affect how hospitable our skin is to the various species of microbes.

我们碰、吃、喝、洗的所有东西，都有可能在皮肤上引入新的微生物。此外，遗传变异也会影响我们的皮肤对各种微生物的好客度。

This may be through genetically controlled production of proteins in the skin that act as barriers and prevent microbes from establishing and growing on the skin, or through more mundane aspects such as a person’s tendency to sweat or how oily their skin is.

比如说，我们可以通过基因控制皮肤上的蛋白质生产，而这些蛋白质可作为一道屏障，从而阻止微生物的停留与繁殖。再或者说，人体的出汗倾向与皮肤油性，也会影响微生物群的组成。

It’s worth remembering that, as pure sweat has no discernible odour, sweating itself may not be responsible for attracting mosquitoes.

值得记住的是，由于纯净的汗水没有可辨别的气味，因此出汗本身可能并不是吸引蚊子的原因。