科學家稱蒼蠅能給驗屍提供線索

As soon as a person dies, decomposition begins. And the first visitors arrive.

人一死亡，分解過程就開始了。參與分解的首批訪客也隨之而來。

"Within five to 15 minutes of death, blowflies or other insects begin to colonize the body." Rabi Musah, an organic chemist at the University at Albany.

奧爾巴尼大學的有機化學家拉比·穆薩表示：“人死後五到十五分鐘內，蒼蠅或其他昆蟲便開始佔領屍體。”

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."

她表示，不同物種在不同的分解階段出現。“因此，依據發現的昆蟲學證據，可以從昆蟲的死亡時段來了解死者的死亡時間。”

Flies don't tend to stick around when disturbed—by detectives, for example. But they do leave behind eggs.

當受到干擾時，蒼蠅便不會在附近逗留，比如它們會被偵探打擾。但是它們會留下卵。

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.

僅憑外觀很難分辨這些是哪種昆蟲的卵，所以法醫昆蟲學家會把它們養大直至孵化，幾周後他們就會知道這是哪個物種，再稍加猜測，便可推斷出一個人的死亡時間。

But Musah has come up with a less time-intensive approach: chemical analysis of the eggs.

但是穆薩提出了一種更省時的方法：對蟲卵進行化學分析。

She and her team investigated that method by first harvesting flies with pig-liver traps stashed throughout New York City.

她和她的團隊將豬肝藏到紐約市各處，作爲誘餌來誘捕蒼蠅，以此來對這種方法進行研究。

"So it turns out that it's easy to hide pig livers in various parts of Manhattan. There's a lot of foliage and whatnot, so no one knew."

“結果發現，在曼哈頓各個地方藏豬肝很容易。有很多植物樹葉可以藏東西，沒人會知道。”

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.

他們將捕獲的蒼蠅收集起來，然後用化學方法分析蠅卵。結果發現，每種蠅卵都有一種獨特的化學指紋圖譜，不用等卵發育成熟也可以分辨它們。

And in a useful twist, the technique uses eggs preserved in alcohol—eggs that wouldn't be viable for rearing live insects anyway.

另外，這種方法還應用了將卵保存在酒精中的技術，使卵不能孵化出活體昆蟲。

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."

現在，穆薩和同事詹妮弗·羅薩蒂將在一個真實案例上測試這種方法。“進行測試以後，我們將發表一些案例研究結果，以證明這種方法可行，希望它最終成爲在法庭上站得住腳的證據。”

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

而且這種方法還能提高破案效率，或在破解懸案上提供幫助。