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  3. 　　More than 40% of insect species are declining and a third are endangered. The rate of extinction is eight times faster than th

　　More than 40% of insect species are declining and a third are endangered. The rate of extinction is eight times faster than th

admin2021-09-25  6
问题 　　More than 40% of insect species are declining and a third are endangered. The rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2. 5% a year, according to the best data available, suggesting they could vanish within a century. The planet is at the start of a sixth mass extinction in its history, with huge losses already reported in larger animals that are easier to study. But insects are by far the most varied and abundant animals, outweighing humanity by 17 times.
    Butterflies and moths are among the worst hit. For example, the number of widespread butterfly species fell by 58% on farmed land in England between 2000 and 2009. The UK has suffered the biggest recorded insect falls overall, though that is probably a result of being more intensely studied than most places. Bees have also been seriously affected, with only half of the bumblebee species found in Oklahoma in the US in 1949 being present in 2013. The number of honeybee colonies in the US was 6 million in 1947, but 3. 5 million have been lost since. There are more than 350,000 species of beetle and many are thought to have declined. But there are also big gaps in knowledge, with very little known about many flies, ants, aphids, shield bugs and crickets. Experts say there is no reason to think they are faring any better than the widely studied species.
    " The main cause of the decline is agricultural intensification," Sanchez-Bayo at the University of Sydney said. "That means the elimination of all trees and shrubs that normally surround the fields, so there are plain, bare fields that are treated with synthetic fertilisers and pesticides. " He said the demise of insects appears to have started at the dawn of the 20th century, accelerated during the 1950s and 1960s and reached "alarming proportions" over the last two decades. He thinks new classes of insecticides introduced in the last 20 years, including neonicotinoids and fipronil, have been particularly damaging as they are used routinely and persist in the environment. They sterilise the soil, killing all the grubs. This has effects even in nature reserves nearby; the 75% insect losses recorded in Germany were in protected areas.
    Other scientists agree that it is becoming clear that insect losses are now a serious global problem. " The evidence all points in the same direction," said Professor Dave Goulson at the University of Sussex in the UK. "It should be of huge concern to all of us, for insects are at the heart of every food web, they pollinate the large majority of plant species, keep the soil healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects. "
    It is gravely sobering to see this collation of evidence that demonstrates the pitiful state of the world’s insect populations. It is increasingly obvious that the planet’s ecology is breaking and there is a need for an intense and global effort to halt and reverse these dreadful trends.
Which of the following might be the best title for this text?
选项 A、Descending Insect Numbers Threaten the Nature
B、Insect Products Remain lucrative in the Global Market
C、Human Beings Kill More Insects than Necessary
D、Enhancing Insect Research and Monitoring is Needed
答案A
解析 主旨题。本文一二段阐述了昆虫数量下降的规模，第三段点名了原因，第四段和第五段主要论述昆虫消亡对生态环境的威胁，综合文章大意，答案选[A]。
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