VOA慢速英语--Scientists Say Many ‘Good’ Insects Are Disappearing

 

It is common to see many different kinds of insects while spending time outside in the summer. Some of these tiny creatures do not bother people and can even add beauty to the natural environment. Examples of these are insects like ladybugs, butterflies and fireflies.

Other insects can harm the environment or humans. Many are known to bite or sting¹. Some carry dangerous diseases. This group includes insects like mosquitoes, ticks and cockroaches². The population of these insects seems to stay large and healthy.

But scientists say this does not appear to be true for some flying insects that serve an important purpose. There is growing evidence that these insects are decreasing across the world.

Many of these insects are very important to plant growth and development. They also serve as a necessary link in the food chain and can help break down life when animals die.

One researcher looking into the current insect population is Doug Tallamy, a professor at the University of Delaware. He worries that a continual drop in the number of helpful insects could lead to disastrous³ results.

If the insects disappeared, Earth’s important life forms would begin to go away too, Tallamy told the Associated Press. This could result in a total breakdown⁴ of the ecosystem⁵.

“How much worse can it get than that?” he asked.

Tallamy noted⁶ a statement by one of America’s best-known biologists, E.O. Wilson of Harvard University. Wilson once called insects “the little things that run the world.”

Wilson is now 89 years old. He told the AP that he remembers walking through Washington, D.C., in the past when it was “alive with insects, especially butterflies.”

Now, he said, “the flying insects are virtually gone.”

Wilson said this point seemed to be confirmed during a drive he made last year from Boston, Massachusetts, to the neighboring state of Vermont. He was surprised that, during his trip, he counted only one insect that had hit the car’s front window.

Several other scientists have carried out similar tests by checking how many insects hit their cars while traveling. An insect researcher from the University of Florida, Philip Koehler, reported that far fewer insects hit his vehicle today than in the past.

While researchers admit this method is not scientific, they say it can still help them understand the changing insect population.

Scientists say there are likely many reasons for the drop in flying insects. Most are related to the destruction of insect habitat caused by things like insecticides, other animals, pollution and climate change.

There have not been many studies done on the insect populations covering large areas. However, some international research suggests a downward turn.

In 2006, a group of studies estimated there had been a 14-percent drop in ladybugs in the United States and Canada from 1987 to 2006.

In Costa Rica, researchers have been studying the flying insect population at the La Selva Biological Station since 1991. One of the researchers is Lee Dyer from the University of Nevada, Reno. He told the AP his team has repeatedly examined a big trap that would have been covered with insects decades ago. Now, they find no insects in the trap.

In Germany, a 2017 study found an 82-percent drop in the number of flying insects captured in 63 traps across the country, compared to levels recorded in 1990. This is the main insect population study carried out so far.

Researchers say it is difficult making similar comparisons in other areas. That is because similar insect counts were not done decades ago.

After the German study, other countries also started looking into the problem. Toke Thomas Hoye of Aarhus University in Denmark studied flies in a few areas of rural Greenland. He said he discovered an 80-percent drop in the insects since 1996.

David Wagner of the University of Connecticut says other evidence leads him to believe the findings of the 2017 study are “clearly not a German thing.” Wagner has measured drops in moth⁷ populations in the northeastern United States.

“We just have to find out how widespread the phenomenon is,” he said.

I’m Bryan Lynn.

Words in This Story

bother – v. annoy, worry or cause problems for someone

sting – v. produce a small but painful injury by making a small hole in the skin

ecosystem – n. all the plants, animals and people living in an area considered their environment

virtually – adv. almost

habitat – n. the natural surroundings in which a plant or animal usually lives

insecticide – n. chemical substance used to kill insects

phenomenon – n. someone or something considered special because it is completely different or extremely unusual

1 sting   

vt.激怒，刺痛，刺伤，蛰伤；n.刺痛，刺伤

参考例句：

• Most flies do not sting.大多数苍蝇不叮人。
• The scorpion has a sting that can be deadly.蝎子有可以致命的螫针。

2 cockroaches   

n.蟑螂( cockroach的名词复数 )

参考例句：

• At night, the cockroaches filled the house with their rustlings. 夜里，屋里尽是蟑螂窸窸瑟瑟的声音。 来自辞典例句
• It loves cockroaches, and can keep a house clear of these hated insects. 它们好食蟑螂，可以使住宅免除这些讨厌昆虫的骚扰。 来自百科语句

3 disastrous   

adj.灾难性的，造成灾害的；极坏的，很糟的

参考例句：

• The heavy rainstorm caused a disastrous flood.暴雨成灾。
• Her investment had disastrous consequences.She lost everything she owned.她的投资结果很惨，血本无归。

4 breakdown   

n.垮，衰竭；损坏，故障，倒塌

参考例句：

• She suffered a nervous breakdown.她患神经衰弱。
• The plane had a breakdown in the air,but it was fortunately removed by the ace pilot.飞机在空中发生了故障，但幸运的是被王牌驾驶员排除了。

5 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

6 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

7 moth   

n.蛾，蛀虫

参考例句：

• A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
• The sweater is moth-eaten.毛衣让蛀虫咬坏了。