科学美国人60秒 SSS Flying Through a Corpse's Clues（在线收听）

Flying Through a Corpse's Clues

能帮法医验尸的苍蝇

As soon as a person dies, decomposition begins. And the first visitors arrive. "Within five to fifteen minutes of death, blow flies or other insects begin to colonize the body." Rabi Musah, an organic chemist at the University of Albany.

人一旦死亡，分解便马上开始。第一批访客也会随之而来。“人死后五到十五分钟内，苍蝇或其他昆虫便会开始在身体中繁殖。”奥尔巴尼大学的有机化学家拉比·穆萨说道。

She says different species turn up at different stages of decomposition. "Because of that, depending on what entomological evidence you find, you can learn something about when the person died in terms of the timing of the death."

她说，不同的物种会在不同的分解阶段出现。“因此，根据发现的昆虫学证据，可以从死亡时间段的角度了解到一个人的死亡时间。”

\Flies don't tend to stick around when disturbed—by detectives, for example. But they do leave behind eggs. The eggs are hard to tell apart by appearance alone, so forensic entomologists rear them until they hatch, a few weeks later—getting a species ID, and, with a little guesswork, a person's time of death.

例如，当侦探来打扰时，苍蝇便不会在附近逗留，但它们却会留下苍蝇卵。这些卵很难单凭外观观察就能被分辨出来，因此法医昆虫学家们会把它们养大，直到它们孵化，然后几周后拿到一个物种ID，加上一点猜测便会得出一个人的死亡时间。

But Musah has come up with a less time-intensive approach: chemical analysis of the eggs. She and her team investigated that method by first harvesting flies with pig liver traps, stashed throughout New York City. "So it turns out that it's easy to hide pig livers in various parts of Manhattan. There's a lot of foliage and what not, so no one knew."

但是穆萨提出了一种更省时的方法：对卵进行化学分析。她和她的团队通过将猪肝藏到纽约市各处设置诱捕苍蝇的陷阱，来对这种方法进行了研究。“所以事实证明，曼哈顿各区都很容易藏匿猪肝。那里有很多植物树叶等等，所以没人会知道。”

They collected the trapped flies, and then chemically analyzed their eggs. And it turns out each species of fly egg has a unique chemical fingerprint—enough to tell the bugs apart without raising the eggs to maturity. And in a useful twist, the technique uses eggs preserved in alcohol—eggs that wouldn't be viable for rearing live insects anyway. The study is in the journal Analytical Chemistry.

她们将捕获的苍蝇收集起来，然后用化学方法分析它们的卵。结果发现，每一种苍蝇卵都有一种独特的化学指纹图谱——足以在不让卵发育成熟的情况下分辨它们。此外，这项技术还利用了将卵保存在酒精中的方法，致使昆虫无法在卵上繁殖。这项研究发表在《分析化学》杂志上。

Musah and her colleague Jennifer Rosati are now testing the method on a real case. "And once we do that we will be publishing some case studies to illustrate that this is a method that can be used, and hopefully eventually it's something that will stand up in court."

穆萨和她的同事詹妮弗·罗萨蒂现在正将这一方法用在一个真实案例上进行测试。“一旦我们这样做了，我们就将能够发表一些案例研究来说明这是一种可行的方法，并且希望最终它能成为在法庭上站得住脚的证据。”

And something that could speed up detective work—or help revive a cold case.

而且它还能加速破案进程——或者帮忙解决一些旧案悬案。