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Farmer Giles the beetle
Like some ants and termites, ambrosia beetles grow crops.
People were not the first farmers. Several groups of ants, and one of termites, were tending fungal plantations for millions of years before Homo sapiens strode the planet. But ants and termites are social insects, able to spread the labour of running their estates among many pairs of jaws. Beetles, by contrast, are solitary. Yet work just published in the Proceedings of the Royal Society by Janina Diehl and Peter Biedermann of the University of Freiburg, in Germany, confirms the agricultural skills of at least one group of coleopterans.
The fruit-tree pinhole borer, as its name implies, bores holes in fruit trees. It lays its eggs and raises its young in the galleries thus created. Yet ambrosia beetles, of which this is a particularly pesky example, do not feed directly on the wood they bore into. Instead, they devour fungi which grow on the timber thus exposed.
Researchers have long suspected that this is a form of farming, because they have evidence the insects carry spores of their preferred crop, Raffaelea sulphurea, into their smallholdings—in effect, sowing it there. Now, Dr Diehl and Dr Biedermann have shown they also engage in another crucial agricultural practice, weeding.
Observations of natural fruit-tree pinhole-borer dwellings suggest that R. Sulphurea grows in them more abundantly than might be expected, given all the fungal competition around—but not why. To check whether the beetles are, indeed, weeding their crop Dr Diehl and Dr Biedermann did an experiment. They raised 40 captives in enclosures that gave them access to test-tubes filled with compacted beech sawdust which had been enriched with salts, sugar, starch and casein (a protein derived from milk), to mimic the nutrient value for fungi of the sort of wood that pinhole borers bore into. Then they watched what happened.
The beetles lived up to their name, creating galleries in the substitute wood quite similar to those they excavate in trees. As with natural galleries, they rapidly inoculated the walls of these tunnels with R. sulphurea spores. Around ten days later, when the fungi were flourishing, but before the beetles had started laying their eggs, the researchers collected all of the insects. They then returned half to their dwellings while leaving the other labyrinths vacant. Twenty days after that, they sampled the gallery walls for fungi.
As they had hoped and expected, R. Suphurea was much more abundant in beetle-tended galleries than in those deprived of their residents. In the former, it made up half of the fungal mass extracted. In the latter, less than a third. These beetles, and by implication other species of ambrosia beetle, are indeed weeding their crop. How this weeding happens remains unknown. But happen it does.
注释：
Gile: n
英文名,中文译为“贾尔”，在国外通常给人第一印象是坚定不移、手脚麻利，一丝不苟.
Ambrosia：n
表示“ 神的食物；特别美味的食物 ”，means " the food and drink of the gods; mortals who ate it became immortal“，如：He finds sweet ambrosia and rubiate nectar.他都发现了甜甜的神食和鲜红的神酒。
Ambrosia beetle: 殖菌蠢虫
termites: n
表示“ 白蚁 ”，means "whitish soft-bodied ant-like social insect that feeds on wood “，如：Remedy is spraying anti - termite syrup. 补救方法是喷洒防白蚁药水。
fungal: adj; n
1. adj表示“ 真菌的；由真菌引起的 ”，means "of or relating to fungi “，如：Athlete's foot is a fungal infection. 运动员的脚部是真菌感染。
2. n表示“真菌”，means "=fungus “，如：My roses were suffering from fungal. 我的玫瑰受到真菌的侵害。
coleopterans: n
表示“ [昆]甲虫类之昆虫；鞘翅类之昆虫 ”
pinhole: n
表示“ 针眼；小孔 ”，means " a small puncture that might have been made by a pin“，如：He then shines a narrow beam in horizontally through the pinhole. 然后他通过小孔水平地射入一窄光束。
spore : n
表示“ 孢子 ”，means " a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria and protozoans and that are capable of developing into a new individual without sexual fusion;“，如：Mushroom's spores are usually carried on the wind. 蘑菇的孢子通常由风传播。
compact: v
表示“ 紧密的；紧凑的；”，means " closely packed together; “，如：He received a compact package. 他收到一个扎得很紧的包裹。
beech: n
表示“山毛榉 ”，means "any of several large deciduous trees with rounded spreading crowns and smooth grey bark and small sweet edible triangular nuts enclosed in burs; north temperate regions “，如：There are many beeches in this wood. 这片树林里有许多山毛榉。
Sawdust: n
表示“ 锯屑 ”，means "fine particles of wood made by sawing wood “，如：Sawdust was scattered on the floor. 地板上撒上了锯木屑
casein: n
表示“ 干酪素；酪蛋白”，means " a milk protein used in making e.g. plastics and adhesives“，如：The casein micelle is important industrially because it is destabilized, resulting in precipitation or coagulation, by acidification and rennetting. 酪蛋白有重要的工业利用价值,因为它不稳定,加酸或凝乳酶作用便可以使其凝固或沉淀。
excavate: v
表示“ 挖掘；挖开”，means "recover through digging “，如：It took a long time to excavate the ancient city of Troy. 挖掘古老的特洛伊城，花了很长时间
inoculate: v
表示“ 给 ... 注射疫苗；灌输 ”，means "perform vaccinations or produce immunity in by inoculation “，如：A corps of doctors arrived to inoculate the recruits. 一队医生来给新兵打防疫针。
labyrinths: n
表示“ 迷宫, 迷路”，如：he went on the Research on Clearance of Labrinth Seal . 他继续迷宫密封的间隙研究
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