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This is Scientific American's 60-second Science, I'm Bob Hirshon.

这里是科学美国人——60秒科学系列，我是鲍勃·赫尔尚。

Most animals are pretty good at avoiding the embarrassing faux pas of having sex with the wrong species. But what if you're a millipede under a cramped¹, dark, slippery rock with a dozen or more species all scurrying² about, looking for love?

大多数动物都能很好地避免与其它动物交配这种尴尬的失误。但如果你是在狭窄、黑暗、光滑的石头下，与十几种或更多物种一起乱爬、寻找爱情的马陆呢？

Fortunately, the critters evolved a solution: elaborate male gonopods—literally "genital feet"—with all manner of branches, bumps and bristles³. And even with 12,000 species of millipedes, no two varieties of gonopods are exactly the same. So the little arthropods can immediately tell if they're consorting⁴ with the wrong species—convenient not only for the millipedes, but also for biologists.

幸运的是，这些生物进化出了解决方案：复杂的雄性生殖肢——字面意思是“生殖脚”，即有着各种各样的分支、隆起和刚毛。虽然有12000种马陆，但没有两种生殖肢是完全相同的。因此，这些小节肢动物能迅速判出是否在与错误的物种交配——这一点不仅方便了马陆，还方便了生物学家。

"So you just have to pick it up and look at it and you say, yup, that's the species, and you can identify it."

“你只需要拿起它观察，然后说，‘对，这就是马陆，'之后你就可以认出来。”

That's millipede researcher Petra Sierwald at the Field Museum in Chicago. The only problem is—no offense⁵ to any male millipedes—the gonopods are tiny.

芝加哥菲尔德博物馆的马陆研究员佩特拉·西尔瓦尔德说到。唯一的问题是——无意冒犯任何雄性马陆——它们的生殖肢很小。

"If you look at a millipede, it's not that big to begin with. So you can imagine their modified legs... are even smaller."

“如果你观察马陆，它们的生殖肢一开始没有那么大。所以你可以想象它们改进过的腿……甚至更小。”

Now, before we go any further, you might be wondering, "Who cares about millipedes, let alone their genitals?" And the answer is, not enough of us. Millipedes are believed to be the first land animals, lured⁶ out of the water by tasty dead vegetable matter on earth's primeval shores.

现在，在我们进一步讨论之前，你可能会想，“谁会关心马陆啊，更不用说它们的生殖器了？”答案是，我们的关注不够。马陆被认为是最早的陆地动物，被地球原始海岸上美味的死亡植物物质引诱出水面。

"They have been in the business of waste management for 460 million years. And that means they are eating rotting vegetation. That returns the nutrients⁷ to the soil. And the healthy soil is what we need to grow our food."

“它们从事废物管理工作已有4.6亿年。这意味着它们在吃腐烂的植物。这种行为可将养分送回土壤。健康的土壤是我们种植食物所必须的。”

But today there aren't enough millipede researchers to determine if their populations are stable and healthy. In fact, Sierwald says there are thousands of unknown millipede species out there, just tapping their many, many, many, many feet, waiting to be noticed.

但如今，没有足够的马陆研究者能确定其种群是否稳定和健康。事实上，西尔瓦尔德表示，存在数千种未知马陆物种，它们正踏着许许多多、许许多多的脚等待被注意。

Which brings us back to gonopods. Recently Sierwald and her colleagues decided⁸ to shine ultraviolet light onto the millipede collection at the Field Museum, because that's just exactly the sort of thing people who work in museums do.

这将我们带回生殖肢这个话题。最近，西尔瓦尔德和同事决定用紫外线照射菲尔德博物馆的马陆收藏品，因为这正是博物馆工作人员所做的事情。

"We found... that their copulatory organs fluoresce."

“我们发现……它们的交配器官会发出荧光。”

And not just with one color, which would have been cool enough.

荧光不只一种颜色，而能发出一种颜色就已经够酷了。

"Different parts of this copulatory organ will fluoresce in different colors: blue, greenish, bluish-greenish and yellow." The finding is in the Zoological Journal of the Linnean Society.

“交配器官的不同部位会发出不同颜色的荧光：蓝色、绿色、蓝绿色 黄色。”这一发现发表在《林奈学会动物学杂志》上。

As to why the male sex organs fluoresce, Seirwald says no one—perhaps not even the millipedes themselves—know for sure. But the color-coded private parts do make identifying millipedes much easier for scientists. Sierwald and her colleagues are now working to photograph different species.

至于为什么雄性的生殖器官会发出荧光，西尔瓦尔德说，没有人——也许连马陆自已——都不能确定原因。但是，用颜色编码的隐私部位，确实令科学家更易识别马陆。西尔瓦尔德及其同事现在在正致力于为不同种类的马陆拍照。

"We need pictures of the male gonopods, and we need them online, and we need them fast!"

“我们需要雄性生殖肢的照片，我们在线等，很急！”

So that scientists can help millipedes keep the soil healthful, for them and for us.

这样科学家就能帮助马陆保持土壤健康，这对它们和我们都有益。

Thanks for listening for Scientific American — 60-Second Science. I'm Bob Hirshon.

谢谢大家收听科学美国人——60秒科学。我是鲍勃·赫尔尚。