(B)
In the past two years, scores of scientific studies have suggested that trillions of murmuring,
droning, susurrating honeybees, butterflies, caddisflies, damselflies and beetles are dying off. Most
of the studies describe declines of 50% and more in different measures of insect health over decades.
The immediate reaction is consternation. Because insects enable plants to reproduce, through
pollination, and are food for other animals, a collapse in their numbers would be catastrophic. “The
insect apocalypse is here,” trumpeted the New York Times last year.
Yet only a handful of databases record the abundance of insects over a long time. There are no
studies at all of wild insect numbers in most of the world, and reliable data are too scarce to declare a
global emergency. Where the evidence does show a collapse—in Europe and America—agricultural
and rural ecosystems are holding up. Plants still grow, attracting pollinators and reproducing. Farm
yields also remain high. As some insect species die out, others seem to be moving into the niches
they have left, keeping ecosystems going, albeit with less biodiversity than before.
People rely on healthy ecosystems for everything from nutrient cycling to the local weather,
and the more species make up an ecosystem, the more stable it is likely to be. The scale of the
observed decline raises doubts about how long ecosystems can remain resilient. An experiment in
which researchers gradually plucked out insect pollinators from fields found that plant diversity held
up well until about 90% of insects had been removed. Then it collapsed. As one character in a novel
by Ernest Hemingway says, bankruptcy came in two ways: “gradually, then suddenly.”
【題組】36. In Europe and America, what happens when some insect species become extinct?
(A) The insect decrease wreaks significant economic damage.
(B) With less biodiversity, the ecosystem continues with great difficulty.
(C) The environmental health remains intact.
(D) The sudden collapse of the ecosystem is expected.
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