密歇根新闻广播 郊区青蛙的一些不可思议的事实

Past studies have found strange things happening to frogs when they're exposed to farm chemicals. A new study shows estrogen in suburban¹ areas is messing with frogs' hormonal² systems too.

More females frogs than males

David Skelly is an author of the study. He's the director of the Yale Peabody Museum of Natural History and a professor of ecology in the Yale School of Forestry³ and Environmental Studies.

In the study, Skelly and his team studied green frogs living in ponds and suburban areas and they compared them to frogs living in undeveloped forests.

"The most striking thing we saw is that the sex ratio — that is the number of males versus⁴ females that we recovered in the ponds that we studied, and we looked at over 20 ponds — gradually trended towards more females when we were working in ponds that were in more developed, more suburbanized sites," Skelly says. "And that was really surprising."

A possibility: Male frogs could be turning into females.

Skelly says a potential explanation is that male frogs are being "sex-reversed."

"So you have genetic⁵ males becoming, in terms of their morphology and perhaps their physiology⁶, they're turning into females because of the chemicals they're encountering in the environment," he says.

But Skelly says they need to do more tests to see whether this is happening in these suburban sites.

Unknown consequences

A suburban pond and frog home.Credit Max Lambert/YaleEdit | Remove

What happens to frog populations when the sex ratio changes and there are more females than males?

"Well, that's a really good question," Skelly says. "And we don't know yet."

Before the effects on frog populations can be determined⁷, Skelly says it's crucial to figure out whether the extra females in these frog populations are functional⁸.

"Are they capable of having offspring or are they sterile⁹? We don't know yet and we're very anxious to find out," he says.

So where does the estrogen that's affecting frogs in suburban areas come from?

Skelly says that answer is complex. He says estrogen in the environment comes from many sources.

"It's everything from brake pads to components¹⁰ of plastics to — in other contexts, we've found that, you know, whatever goes into your domestic wastewater is likely to be getting in there," he says.

He also says many different kinds of metals can get into the environment from cars and household products.

"So it's really kind of comprehensive," he says.

Skelly says there's probably not a "single smoking-gun-type explanation."

"The idea that atrazine or any single chemical is going to be the one to cause this kind of phenomenon, as broadly as it's been documented, is probably not right," he says. "Instead, what we're probably looking at is that there are a wide variety of sources for the kinds of chemicals that can cause these sorts of changes in animals."

Tackling the problem

In the same way, Skelly says there's not a simple fix for this issue. That too must be addressed more comprehensively.

"We're not going to be able to just get, for instance, you know plasticizers, like BPA, out of baby bottles or just de-register one kind of pesticide¹¹ and take care of the problem," he says. "Not that those things might not make some kind of a difference. But they're not going to be comprehensive, effective solutions."

To learn more, see this interview with David Skelly by Yale Environment 360.

1 suburban   

adj.城郊的，在郊区的

参考例句：

• Suburban shopping centers were springing up all over America. 效区的商业中心在美国如雨后春笋般地兴起。
• There's a lot of good things about suburban living.郊区生活是有许多优点。

2 hormonal   

adj.激素的

参考例句：

• Some viral diseases are more severe during pregnancy, probably tecause of hormonal changes. 有些病毒病在妊娠期间比较严重，可能是由于激素变化引起的。
• She underwent surgical intervention and a subsequent short period of hormonal therapy. 他接受外科手术及随后短暂荷尔蒙治疗。

3 forestry   

n.森林学；林业

参考例句：

• At present, the Chinese forestry is being at a significant transforming period. 当前, 我国的林业正处于一个重大的转折时期。
• Anhua is one of the key forestry counties in Hunan province. 安化县是湖南省重点林区县之一。

4 versus   

prep.以…为对手，对；与…相比之下

参考例句：

• The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
• The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。

5 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

6 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

7 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

8 functional   

adj.为实用而设计的，具备功能的，起作用的

参考例句：

• The telephone was out of order,but is functional now.电话刚才坏了，但现在可以用了。
• The furniture is not fancy,just functional.这些家具不是摆着好看的，只是为了实用。

9 sterile   

adj.不毛的，不孕的，无菌的，枯燥的，贫瘠的

参考例句：

• This top fits over the bottle and keeps the teat sterile.这个盖子严实地盖在奶瓶上，保持奶嘴无菌。
• The farmers turned the sterile land into high fields.农民们把不毛之地变成了高产田。

10 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

11 pesticide   

n.杀虫剂，农药

参考例句：

• The pesticide was spread over the vegetable plot.菜田里撒上了农药。
• This pesticide is diluted with water and applied directly to the fields.这种杀虫剂用水稀释后直接施用在田里。