英语听力：自然百科 萤火虫为何会发光？

 This week on Why? Tell Me Why! We are answering a viewer question as to why lightning bugs² light up.

 

Lightning bugs light up basically to find a mate. It’s a way that lightning bugs communicate with each other, to call each other together, because someone’s looking for a mate. They have these features in the abdomen³ of the body: they light up and they can control when they light up, when they blink and how long they blink. And they use that blinking signal to attract each other.

 

Do both males and females have the lights?

 

They both have the lights, but the females have brighter lights and bigger lights because they are the ones who are trying to attract males to them. Each different species of lightning bug¹ has a different pattern of flashing to only attract its own species. In this way, if there are five different species of lightning bugs all in the same field, they can tell who is their same species and who is not. So, they know who to be attracted to. There is an enzyme⁴ in these insects called luciferase. And it uses something that insects make from the food they eat to bind⁵ together and generate light with very little heat. So, one of the interesting things about fireflies is they generate this light without making heat.

 

The only time we see lightning bugs lighting⁶ up is when they are on a quest to find a mate? That’s a, that’s one time they'll use their lights?

 

There is one other time when lightning bugs will use their lights and that is there is one species of lightning bugs that uses the light to attract other lightning bugs which she will aim to eat.

1 bug   

n.虫子；故障；窃听器；vt.纠缠；装窃听器

参考例句：

• There is a bug in the system.系统出了故障。
• The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。

2 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

3 abdomen   

n.腹，下腹(胸部到腿部的部分)

参考例句：

• How to know to there is ascarid inside abdomen?怎样知道肚子里面有蛔虫？
• He was anxious about an off-and-on pain the abdomen.他因时隐时现的腹痛而焦虑。

4 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

5 bind   

vt.捆，包扎；装订；约束；使凝固；vi.变硬

参考例句：

• I will let the waiter bind up the parcel for you.我让服务生帮你把包裹包起来。
• He wants a shirt that does not bind him.他要一件不使他觉得过紧的衬衫。

6 lighting   

n.照明，光线的明暗，舞台灯光

参考例句：

• The gas lamp gradually lost ground to electric lighting.煤气灯逐渐为电灯所代替。
• The lighting in that restaurant is soft and romantic.那个餐馆照明柔和而且浪漫。