关注本公众号，回复“进群”进经济学人打卡群
概要：本文通过澳大利亚养牛业的案例，讲述了屎壳郎对农场养殖的积极意义。屎壳郎不仅能够清理粪便，让牛有更多时间增重，而且还能阻止寄生虫在牛群中传播，帮助土壤中的营养物质循环，并通过防止粪便进入溪流，从而改善水质。更重要的是，在真菌抗药性越来越强的今天，能够有效抑制真菌的生长。（生词在最后）
The noisome economics of dung beetles 屎壳郎经济学
They are worth millions a year to cattle ranchers 屎壳郎每年为养牛户带来数百万美元的价值
September 2nd 2024
THE ENGLISH colonists who brought cattle to Australia in 1788 soon faced a malodorous problem. The dung heaps that gradually and tastefully vanished back home were not going anywhere. Instead, they were growing ever-larger, and becoming infested with bloodsucking flies that wounded the livestock.
1788 年把牛带到澳大利亚的英国殖民者很快就面临了一个恶臭的问题。在英国，牛粪堆会逐渐且优雅地消失，而在澳大利亚却会留在原地。相反，牛粪会变得越来越大，并且被吸血苍蝇侵扰，这些苍蝇会伤害牲畜。
It took almost two centuries for the explanation to emerge: Australian dung beetles, more used to marsupial droppings than those from cattle, left the deposits where they lay. It was only when European dung beetles were introduced to the country in 1968 that the Australian cattle industry felt the benefits.
花了将近两个世纪才找到这一现象的解释：澳大利亚的屎壳郎更习惯有袋动物的粪便，不习惯牛的粪便，所以它们会把牛粪留在原地。直到 1968 年欧洲屎壳郎被引入澳大利亚，当地养牛业才开始好转。
Stories of this kind bear testament to the important services that dung beetles provide. The most iconic of these bugs gather up defecated material into a ball, roll it away and then bury it underground. Others tunnel underneath faeces and collect it without ever being seen. Some just burrow into dung piles and build a den from within which they feast. All of this activity can provide farmers with economic value, though just how much has long been unclear. In a recent paper in the journal Basic and Applied Ecology, Roisin Stanbrook-Buyer, an ecologist at Bethune-Cookman University in Florida, attempted to calculate an exact figure.
这类故事证明了屎壳郎的重要性。这些虫子的标志性特征是把粪便收集成一个球，滚着埋在地下。有的屎壳郎会在粪便下面挖掘隧道，在不被看到的情况下收集粪便。有些屎壳郎则钻进粪堆，在里面建造一个巢穴，然后享用。所有这些都能为农民带来经济价值，但长期以来价值具体几何人们并不清楚。最近发表在《基础与应用生态学》杂志上的一篇论文中，佛罗里达州白求恩 - 库克曼大学的生态学家罗辛・斯坦布鲁克 - 拜尔试图得出一个确切的数字。
She worked with a team of colleagues to study cattle faeces at two ranches and a state park in south-central Florida and found that the waste in a representative pile vanished at an average rate of 10.7 grams per day when dung beetles were present. By contrast, when the beetles were absent, the faeces vanished at a rate of 3.7 grams per day.
她和同事一起研究了佛罗里达州中南部两个牧场和一个州立公园的牛粪，并发现当有屎壳郎存在时，牛粪堆中的粪便通常会以平均每天 10.7 克的速度消失。相比之下，当没有屎壳郎时，这一速度是每天 3.7 克。
This disparity has consequences. Studies have shown cattle avoid eating in an area up to six times larger than the footprint of the dung. At first, the foul smell is responsible. Once the odour diminishes, however, nutrients in the faeces drive the grasses to mature quickly and become unpalatable. Over time, this can lead large sections of grazing fields to go unused and ultimately affect how quickly cattle fatten. Dr Stanbrook-Buyer found that dung beetles counter these negative effects. She calculates that ensuring a healthy beetle presence on all ranches in Florida would increase statewide revenues by more than $1m a year.
这种差异后果严重。研究表明，牛进食时会避开牛粪周围相当于牛粪占地面积大六倍的区域。一开始，难闻的气味会影响牛的进食。而当臭味减弱，粪便中的营养物质会迅速催熟草丛，使其变得不再可口。随着时间的推移，这会导致大片牧场无法使用，并最终影响牛的增重速度。斯坦布鲁克 - 拜尔博士发现屎壳郎能够抵消这些负面影响。她计算认为，如果佛罗里达州所有牧场都有健康的屎壳郎，每年全州收入将增加 100 多万美元。
This figure may seem small, especially by comparison with the hundreds of millions of dollars that pollinating insects are thought to offer the state each year, but it may well be an underestimate. Among other things, says Dr Stanbrook-Buyer, dung beetles disrupt parasites from spreading in cow populations, help cycle nutrients in the soil and improve water quality by keeping faeces out of streams. Studies conducted in other parts of the world suggest that the sum total of benefits granted to ranchers by the beetles will be in the tens of millions.
这个金额可能看起来不多，尤其是与人们认为的传粉昆虫每年为该州带来的数亿美元相比。但事实上这一金额很可能被低估了。斯坦布鲁克 - 拜尔博士说，除此之外，屎壳郎还能阻止寄生虫在牛群中传播，帮助土壤中的营养物质循环，并通过防止粪便进入溪流，从而改善水质。其他研究表明，屎壳郎给牧场主带来的总收益可达数千万美元。
The true value of these insects, though, goes far beyond merely increasing beef production. Dung beetles are locked in an evolutionary battle with fungi for access to their favoured food. To gain the upper hand, and keep dung fungi-free, they groom it with a mixture of their own faeces and saliva. To find out how this concoction works, Mario Favila at the Institute of Ecology in Xalapa, Mexico collected gut bacteria from three dung-beetle species and cultured these microbes in the lab.
然而，这些昆虫的真正价值远远不止于仅仅增加牛肉产量。屎壳郎在获取牛粪时会与真菌展开进化之战。为了占据上风并使粪便中没有真菌，它们会用自己的粪便和唾液的混合物来清理牛粪。为了了解这种混合物，墨西哥哈拉帕生态研究所的马里奥・法维拉从三种屎壳郎体内收集肠道细菌，并在实验室中培养这些微生物。
Working with a team of colleagues, he then exposed them to nine strains of pathogenic fungi that cause serious problems in agriculture. The team reports in Science of Nature that the microbes found in two of the dung-beetle species were very effective at hampering the growth of seven of the fungi. The microbes from the third species, Onthophagus batesi, significantly decreased the growth of all nine. With pathogenic fungi becoming ever more resistant to existing anti-fungals, dung beetles have never looked more attractive. ■
然后，他和同事一起将这些细菌暴露在九种会给农业带来严重问题的致病真菌菌株中。该团队在《自然科学》杂志上报告说，在两种屎壳郎的肠道细菌在抑制七种真菌的生长方面非常有效。第三种屎壳郎 —— 巴氏嗡屎壳郎能显著抑制所有九种真菌的生长。在致病真菌对现有抗真菌药物抵抗力越来越强的今天，屎壳郎从未变得如此具有吸引力。
加我自动邀请进群
生词：
malodorous /ˌmælˈəʊdərəs/ 有难闻气味的；恶臭的。例句：The room was malodorous after the chemical spill.(化学物质泄漏后房间里有难闻的气味。)
dung /dʌŋ/ 粪；肥料。例句：The farmer spread dung on the field.(农民把粪肥撒在田里。)
infested /ɪnˈfestɪd/ 大批滋生；大批出没于。例句：The house is infested with mice.(这所房子里老鼠成群。)
marsupial /mɑːˈsuːpiəl/ 有袋动物。例句：Kangaroos are marsupials.(袋鼠是有袋动物。)
bear testament to 证明；证实。例句：The old building bears testament to the city's rich history.(这座古老的建筑证明了这座城市丰富的历史。)
defecate /ˈdefəkeɪt/ 排泄；排粪。
faeces /ˈfiːsiːz/ 粪便；排泄物。例句：The dog left its faeces on the sidewalk.(狗在人行道上留下了粪便。)
burrow /ˈbʌrəʊ/ 挖掘（洞穴）；钻进。例句：The rabbit burrowed into the ground.(兔子钻进了地里。)
den /den/ 兽穴；窝。例句：The lion's den was hidden in the bushes.(狮子的巢穴藏在灌木丛中。)
ranch /rɑːntʃ/ 大农场；大牧场。例句：He works on a cattle ranch.(他在一个养牛场工作。)
grazing fields 牧场；草地。例句：The cows are grazing in the fields.(奶牛在牧场上吃草。)
pollinating /ˈpɒləneɪtɪŋ/ 授粉。例句：Bees are important for pollinating flowers.(蜜蜂对花朵授粉很重要。)
microbes /ˈmaɪkrəʊbz/ 微生物；细菌。例句：Microbes play an important role in the ecosystem.(微生物在生态系统中起着重要作用。)
anti-fungals /ˌæntiˈfʌŋɡəlz/ 抗真菌药。例句：The doctor prescribed anti-fungals for the infection.(医生开了抗真菌药治疗感染。)
