科学美国人60秒 SSS 青蛙的声音影响其求偶的偏好

This is Scientific American's 60-second Science, I'm —Jason Goldman.

这里是科学美国人——60秒科学系列，我是杰森·戈德曼。

In the shadow of Huangshan Mountain in southeastern China lives a beige frog with black stripes.

在中国东南部的黄山背光处，生活着一种带有黑色条纹的浅褐色青蛙。

The concave-eared torrent¹ frog, or Odorrana tormota, gets its name from its unusual hearing apparatus².

凹耳洪流蛙(Odorrana tormota)，因其不同寻常的听觉器官而得名。

"It has kind of an ear canal-like structure like humans, and like most mammals.

“它像人类和大多数哺乳动物一样有一种类似耳道的结构。

For most frog species, the eardrums are located on the body's surface, on the lateral³ part of the body surface.

对于大多数蛙类来说，耳膜位于身体表面，在身体表面的侧面。

But here the eardrum is invisible because it is embedded⁴ deep inside the head, in the skull⁵."

但凹耳洪流蛙，耳膜是看不见的，因为它深嵌在头部的头骨中。”

Biologist Albert Feng, from the University of Illinois at Urbana-Champaign.

来自伊利诺伊大学香槟分校的生物学家阿尔伯特·冯说。

Back in 2006, Feng and his colleagues discovered that this unusual anatomy⁶ allows the frogs to hear ultrasound, which includes frequencies greater than 20 Kilohertz.

早在2006年，阿尔伯特·冯和他的同事就发现，这种不同寻常的解剖结构使青蛙能够听到超声波，其中包括频率超过20千赫兹的超声波。

Biologists had always assumed that ability was restricted to some mammals because it was only known in bats, whales, dolphins, and some rodents⁷.

生物学家一直认为这种能力仅限于一些哺乳动物，因为只知道蝙蝠、鲸鱼、海豚和一些啮齿动物有这种能力。

We can’t hear in that range.

我们听不见那个范围的声音。

The streams that the frogs live in are quite noisy, but most of those sounds are low frequency.

青蛙生活的河流非常吵闹，但大多数声音的频率都很低。

By restricting their vocalizations to the higher frequencies, including ultrasound, the frogs are better able to hear each other.

通过将它们的叫声限制在更高的频率，包括超声波，青蛙们能更好地听到彼此的叫声。

"The higher the frequency, the less that signal is distorted, or at least masked, by the ambient noise."

“频率越高，环境噪声影响下的信号失真越少或至少信号被掩盖得越少。”

In many animals, females prefer mating with larger males, usually because that's a sign of health and strength.

在许多动物中，雌性更喜欢与体型较大的雄性交配，通常是因为这是健康和力量的象征。

And bigger males tend to produce lower frequency vocalizations.

体型较大的雄性会发出较低频率的声音。

But with higher frequency calls being more effective in this habitat, Feng wondered if females might actually prefer smaller males.

但在这种栖息地，更高频率的叫声更有效，阿尔伯特·冯想知道雌性是否真的更喜欢小一点的雄性。

Over the course of several nights, the researchers captured thirty-five pairs of frogs engaged in what biologists call amplexus.

通过几个晚上的进展，研究人员捕获了35对处于生物学家所说的抱合状态的青蛙。

Which means while having sex.

也就是说正在交配的时候。

The biologists measured the length of each male, as well as the length of those males found nearby who were unlucky enough to be caught and also not having sex.

生物学家测量了每只雄性的长度，以及在附近发现的那些不幸被捕获且没有交配的雄性青蛙的长度。

Turns out, size really does matter.

事实证明，尺寸确实很重要。

"Yes, the females are very unusual in that they really prefer smaller males over larger males."

“雌性很不寻常，它们真的更喜欢小的雄性而不是大的雄性。”

Next, the researchers brought the frogs into the lab.

接下来，研究人员把青蛙带进了实验室。

Each female was placed alongside two males.

每只雌性被放在两只雄性旁边。

Here, too, females opted⁸ to mate with smaller-bodied males.

在这里，雌性也选择与体型较小的雄性交配。

And an analysis of the mating calls showed that the smaller males did use higher frequency sounds.

对求偶叫声的分析表明，体型较小的雄性确实使用频率更高的声音。

The study was published in the Journal of Zoology⁹.

这项研究发表在《动物学杂志》上。

"We are thinking by females preferentially choosing small-sized males, that actually we can see the trend over generations…you can see the gradual evolutionary¹⁰ changes in the trait.

“我们认为雌性会优先选择体型较小的雄性，实际上我们可以在几代蛙中看到这种趋势……你可以看到这一特征的逐渐进化。”

Over multiple generations you gradually develop these ultrasonic¹¹ capabilities¹²."

经过几代，会逐渐发展这些超声波能力。”

What isn't clear yet is whether the females are visually assessing the males for their size, or whether they just have an easier time hearing their higher-frequency calls—making them more likely to mate with smaller males.

目前尚不清楚的是，雌性是通过视觉判断雄性的体型，还是因为更容易听到它们高频的叫声，从而更有可能与体型较小的雄性交配。

That's exactly what Feng's team is testing now, by broadcasting mating calls to the females in a laboratory—with the lights out.

这正是阿尔伯特·冯的团队现在正在测试的，他们在实验室里关灯向雌性青蛙出交配信号。

Thanks for listening for Scientific American's 60-second Science. I'm Susanne Bard¹³.

感谢收听《科学美国人》60秒科学节目。 我是杰森·戈德曼。

1 torrent   

n.激流，洪流；爆发，(话语等的)连发

参考例句：

• The torrent scoured a channel down the hillside. 急流沿着山坡冲出了一条沟。
• Her pent-up anger was released in a torrent of words.她压抑的愤怒以滔滔不绝的话爆发了出来。

2 apparatus   

n.装置，器械；器具，设备

参考例句：

• The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
• They had a very refined apparatus.他们有一套非常精良的设备。

3 lateral   

adj.侧面的，旁边的

参考例句：

• An airfoil that controls lateral motion.能够控制横向飞行的机翼。
• Mr.Dawson walked into the court from a lateral door.道森先生从一个侧面的门走进法庭。

4 embedded   

a.扎牢的

参考例句：

• an operation to remove glass that was embedded in his leg 取出扎入他腿部玻璃的手术
• He has embedded his name in the minds of millions of people. 他的名字铭刻在数百万人民心中。

5 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

6 anatomy   

n.解剖学，解剖；功能，结构，组织

参考例句：

• He found out a great deal about the anatomy of animals.在动物解剖学方面，他有过许多发现。
• The hurricane's anatomy was powerful and complex.对飓风的剖析是一项庞大而复杂的工作。

7 rodents   

n.啮齿目动物( rodent的名词复数 )

参考例句：

• Rodents carry diseases and are generally regarded as pests. 啮齿目动物传播疾病，常被当作害虫对待。 来自《简明英汉词典》
• Some wild rodents in Africa also harbor the virus. 在非洲，有些野生啮齿动物也是储毒者。 来自辞典例句

8 opted   

v.选择，挑选( opt的过去式和过去分词 )

参考例句：

• She was co-opted onto the board. 她获增选为董事会成员。
• After graduating she opted for a career in music. 毕业后她选择了从事音乐工作。

9 zoology   

n.动物学，生态

参考例句：

• I would like to brush up my zoology.我想重新温习一下动物学。
• The library didn't stock zoology textbooks.这家图书馆没有动物学教科书。

10 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

11 ultrasonic   

adj.超声的；n.超声波

参考例句：

• It was very necessary for people to take type-B ultrasonic inspection regularly.定期进行B超检查是十分必要的。
• Sounds are classified into two kinds: sonic and ultrasonic.声波分为两类，即普通声波与超声波。

12 capabilities   

n.能力( capability的名词复数 )；可能；容量；[复数]潜在能力

参考例句：

• He was somewhat pompous and had a high opinion of his own capabilities. 他有点自大，自视甚高。 来自辞典例句
• Some programmers use tabs to break complex product capabilities into smaller chunks. 一些程序员认为，标签可以将复杂的功能分为每个窗格一组简单的功能。 来自About Face 3交互设计精髓

13 bard   

n.吟游诗人

参考例句：

• I'll use my bard song to help you concentrate!我会用我的吟游诗人歌曲帮你集中精神！
• I find him,the wandering grey bard.我发现了正在徘徊的衰老游唱诗人。