Insects You Love to Hate|令你反感的小家伙

by Brian Foden

Experts believe mosquitoes are possibly the deadliest creatures on Earth.

　　It may be hard to believe that some experts consider tiny mosquitoes to be the most dangerous creatures in the world. However, categorizing these insects _(1)_ dangerous animals makes good sense, considering the fact that mosquito-borne illnesses kill millions of people each year. The list of deadly diseases includes malaria, encephalitis, West Nile virus, yellow fever, and dengue fever. In addition to infecting humans with life-threatening illnesses, mosquitoes also _(2)_ diseases to animals through parasites and viruses.

　　_(3)_ only a few of the 3,500 species of mosquitoes are capable of passing on diseases, the blood-sucking nature of these pests makes them universally hated. Tens of millions of years of evolution have turned mosquitoes into adept hunters with a _(4)_ sense of survival. One way that mosquitoes have evolved to track down potential meals of blood is through sensing carbon dioxide and lactic acid, which are substances emitted by mammals and birds, from a range of up to 36 meters. These insects can also detect heat and use visual _(5)_ to find hosts to feed on. _(6)_ visible clues, mosquitoes are drawn to movement and people wearing clothing that is in contrast to their surroundings.

　　For those wondering why some mosquitoes risk _(7)_ blood from hosts who would gladly kill them, the reason is that the protein found in blood acts as nourishment for producing eggs. In fact, only female mosquitoes suck blood. Males seek out nectar and other sugars to consume.

1.   (A) for       (B) to (C) as       (D) in

2.   (A) transmit     (B) recruit  (C) surpass     (D) intervene

3.   (A) When   (B) While   (C) Unless (D) Until

4.   (A) profitable   (B) parallel (C) logical (D) keen

5.   (A) restraints   (B) sensations (C) thresholds (D) sanctions

6.   (A) On the verge of    (B) In terms of      (C) In place of      (D) For fear of

7.   (A) to be drunk     (B) drink   (C) drinking    (D) to drink

令你反感的小家伙

专家认为蚊子可能是地球上最致命的生物。

　　一些专家将小蚊子视为世界上最危险的生物，这可能对你来说难以置信。然而，有鉴于蚊子带原传播的疾病每年让数百万人丧命的此一事实，将这些昆虫分类为危险动物是很合理的。致命疾病的名单包括疟疾、脑炎、西尼罗病毒、黄热病以及登革热。除了使人类感染到危及生命的疾病之外，蚊子还会透过寄生虫和病毒传播疾病给动物。

　　虽然 3 千 5 百种蚊子当中只有一些能传递疾病，但这些害虫的嗜血本性仍让牠们普遍受到厌恶。数千万年的演化已经把蚊子转变为很有生存感的猎人。蚊子进化成可追踪潜在血液食物的一种方法，即是凭借着感测二氧化碳和乳酸，这些物质会从哺乳动物和鸟类排放出来，感测范围广达 36 公尺。这些昆虫还可以探测到热度并利用视觉找到宿主以求温饱。以显见的线索来看，蚊子会受到动作以及穿着服装与周围环境成对比的人所吸引。

　　对于那些想知道为何有些蚊子要冒着生命危险吸取宿主的血，而宿主却会很乐意打死蚊子的人来说，蚊子吸血的理由就是存在于血液中的蛋白质可作为滋养以助产卵。事实上，只有雌蚊会吸血。雄蚊则是找寻花蜜和其他糖类以供食用。

答案： 1.   C   2.   A   3.   B   4.   D   5.   B

      6.   B   7.   C

 

　　蚊子使用口针，也就是 6 根类似抽血用针的针状构造来刺进人类的皮肤，吸取血液摄食。当蚊子叮咬人类时，会从口器输出唾液。其唾液含有蚁酸、抗凝血剂及目前成分不明的蛋白质（目前已知至少含 15 种），其中酸性物质是用来溶解皮肤表层的角质层；抗凝血剂则是避免在蚊子吸食血液时，血液突然凝固。第 1 次被咬时，身体不会有任何特殊反应。但从第 2 次开始，身体的免疫系统会释放出称为组织胺的物质，以便对抗蚊子所带来的外来物质，造成皮肤发痒和红肿。这种刺激性感觉，乃是被叮咬者对蚊子唾液的过敏反应。（数据源：维基百科）