11-10 昆虫侦探（上）（在线收听）

The Bug Detectives

Forensics¹ has always used anything that science can give us to cope with various crimes. But forensics has always had its limits. In fact there are major factors in any murder that 21st century science still cannot crack². Crucially, for example, even with all our technology, it is impossible for forensic science to estimate the time of death when a body is found more than 72 hours after a murder. For a body that has lain for more than a few days, guesswork is the best forensics can do in telling us how long ago a person was murdered. But, over 100 years ago two disciplines came together entomology³, the study of insects, and forensics, the scientific analysis of crime. But it is only now that this remarkable discipline, Forensic Entomology, is coming into its own and solving the unsolvable.

Dr Dorothy Gennard is a Senior Lecturer in Biological Sciences at Lincoln University. To study what happens to a human body after death or murder scientists like Dr Gennard experiment on pigs. The carcass⁴ of any animal is of intense interest to insects. The first on the scene, within minutes of death, is the common housefly. She quickly decides if the carcass will be a good place to lay her eggs, so that when they hatch⁵, they will have a convenient source of food. When the fly lays its eggs it starts a biological clock ticking. The lifecycle of egg to maggot⁶ to adult fly takes place over a known period of time usually 10 days. By identifying what stage the insect is at, experts can estimate its age and relate this to how long the body has been dead.

Dr. Dorothy Gennard said: “If a body has been found and it is covered in maggots then we can go back and we can identify what species of maggot that is. And we can work out how old that maggot is and therefore the period of time since colonisation⁷ of the body.”

Creatures like flies give us that opportunity to determine that post mortem⁸ interval at a period later than the pathologist⁹ can. The pathologist can tell us how long the person has died up to about 72 hours quite accurately, from there the entomologist is able to add a further dimension. By timing the biological clock of insect activity backwards， vital clues can be discovered about the time of death.

Britain’ s most distinguished forensic entomologist, who has helped solve over 500 criminal cases during 27 years, is Dr Zakaria Erzinciolglu. And in case after case, he is pinpointing¹⁰ time of death months and even years after the death took place, solving murders or mysteries. The classic case, unsolvable by traditional forensics, was the case of the body in the boarded up house. Murder or accident?

The corpse of an old man was discovered lying in bed. His body was infested with maggots. He had no family or friends, indeed no one knew he was there at all, except the insects. The question was, did he die before the house was boarded up or afterwards? There were maggots on the body. The doctor had a sample brought to him by a policeman. Once he had reared¹¹ the maggots to adult flies he made a crucial discovery. The flies in this case were greenbottle flies, they are not normally the sort of fly that you would find indoors, they are only attracted indoors because of the presence of a carcass or a corpse. However it is most unlikely that the body had been somewhere else. There was no evidence that anybody went in and placed the body there and then boarded the house up again. And there were entry points for the flies.

The age of the maggots on the body showed that the minimum time of death was considerably later than the date of the boarding up of the house. We can safely conclude that in fact he did die some time after the house was boarded up. He was alive and he died there without being able to attract attention to himself. Which is quite a horrific way to end one’s life.

注释：         

1. forensics [fE5rensiks] n. 法医学

2. crack [krAk] vt. 破译，侦破，解（难题等）

3. entomology [entEu5mClEdVi] n. 昆虫学

4. carcass [5kB:kEs] n. （鸟、兽的）尸体

5. hatch [hAtF] vi. （蛋）孵化，（小鸡等）出壳，孵出，（母鸡等）孵蛋

6. maggot [5mA^Et] n. [昆]蛆（双翅目昆虫的无足幼虫）

7. colonisation [7kClEnaizeiFEn] n. （动、植物）移植，移生，移地发育

8. post-mortem [7pEust5mCtEm] a. 死后的

9. pathologist [pE5WClEdVist] n. 病理学家

10. pinpoint [5pin7pCint] vt. 准确描述，确认，确定

11. rear [riE(r)] vt. 培植，饲养

昆虫侦探（上）

法医学总是采用我们现有的一切科学知识来对付各种犯罪。但是法医学总有它的局限性。实际上在21世纪的今天，任何一桩谋杀案中都有一些重要疑点是科学仍然无法破解的。例如，非常关键的一点是，尽管采用了所有的科学技术，法医学仍旧无法判断一个已经被谋杀超过72小时的死者的具体死亡时间。对于已被放置超过数天的尸体，猜测是法医学告诉我们这个人何时被谋杀的最好方法。但是，在100多年前，研究昆虫的昆虫学和科学分析犯罪的法医学这两个学科走到了一起。但只是在现在，这一不寻常的学科——法医昆虫学才开始发挥重要作用，解决一些无法解决的问题。

　　多萝西·杰纳德博士是林肯大学生物科学系的高级讲师。为了研究一个人死后或被谋杀后尸体发生的变化，杰纳德博士等科学家用猪来作实验。任何动物的尸体对昆虫都有很强的吸引力。在死亡的数分钟内，首先到现场的是常见的家蝇。它迅速确定尸体是否是产卵的好地方，这样当卵孵化时，它们会有很方便的食物来源。当苍蝇产完卵，它就启动了一个生物时钟。卵变成蛆再变成成年苍蝇的生命周期发生在一个已知的时间段内，通常为10天。通过识别昆虫所处的生命阶段，专家可以估计出它的年龄，并推断出尸体的死亡时间。

　　多萝西·杰纳德博士说：“如果发现了一具尸体，而且上面爬满了蛆，我们就可以把蛆带回去，辨别蛆的种类。接下来，我们可以推算出蛆的年龄，进而推断出死者的死亡时间有多长。”

像苍蝇这样的生物为我们提供了病理学家无法提供的确定死者死亡时间的机会。病理学家可以非常精确地告诉我们72小时以内人的死亡时间，昆虫学家可以推断的时间更长。通过反推昆虫活动的生物钟，就可以发现死亡时间的重要线索。

　　英国最杰出的法医昆虫学家是扎卡里亚·额尔金格鲁博士，他在27年当中已经帮助警方破解了500多个犯罪案件。在一个接一个的案件中，在死者死亡数月甚至数年之后，他可以准确地判断出死亡时间，破解谋杀案或神秘事件。传统法医无法破解的经典案例是，被封闭的屋中的尸体。是谋杀还是意外？

　　一个老人被发现躺在床上，已经死去了。尸体上生了成群的蛆。他没有家人或朋友，事实上，除了昆虫之外根本没人知道他在那里。问题是，他是在屋子被封闭前死亡的，还是在封闭后死亡的呢？尸体上有蛆。博士让警察为他取来了一个样本。等他把蛆培育成成年苍蝇后，他有了决定性的发现。本案中的苍蝇是叉叶绿蝇，并不是在室内很常见的苍蝇种类。只有当室内有尸体时，它们才会被吸引到室内。然而，尸体绝对不可能曾经处于其他地方。没有证据表明，有人曾进来过并把尸体放在那里，然后将屋子重新封闭。而且有苍蝇可以进入的空隙。

尸体上蛆的年龄显示，死者死亡的最早时间比房屋被封闭的时间要晚得多。我们可以有把握地下结论，事实上，他确实是在房屋被封闭之后，过了一段时间死亡的。他当时还活着，但无法吸引人们来注意他，于是死在那里。这是结束一个人生命的非常恐怖的方式。(待续)