Adult blow flies are one of the first necrophagous insects to colonize fresh carcasses. The eggs they lay hatch into larvae, which then feed on the decomposing body. Like all organisms, blow flies “are what they eat,” meaning that the isotopic composition of their body tissues reflects their diet. This manuscript combines ecology with a forensic application by using isotope ratio mass spectrometry (IRMS) to understand the relationship between the δ¹³C of amino acids in different carrion sources and the blow fly that feed on them. We also measure the amino acid-level fractionation that occurs at each major life stage of the blow flies. Adult blow flies from a commercial strain of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) oviposited on raw pork muscle, beef muscle, or chicken liver. Larvae, pupae, and adult blow flies from each carrion were selected for amino acid compound-specific isotope analysis. Canonical discriminant analysis showed that flies were correctly classified to specific carrion types in 100% (original rules) and 96.8% (leave-one-out cross-validation [LOOCV]) of cases. Regarding life stages, we obtained 100% and 71% of correct classification in original rules and LOOCV, respectively. The isotope ratios of most of the essential amino acids did not significantly change between life stages (at 95% CI). However, some non-essential amino acids (Ala, Ser, and Glu) and some conditionally essential amino acids (Gly and Pro) were isotopically depleted in the adult stage. Except for the essential amino acids, the amino acids in larvae and pupae were enriched in ¹³C, and adult blow flies were depleted in ¹³C relative to the carrion on which they fed. These results make it possible to exclude potential sources of carrion as larval food. Amino acid-specific IRMS could help inform entomologists whether a fly has just arrived from another location to feed on a corpse or has emerged from a pupa whose feedstock was the corpse. Such insight could enhance the significance of blow flies for post-mortem interval determinations. The analytical ability to link organisms from one trophic level to another through the use of compound-specific isotope analysis of amino acids could have wide-reaching consequences in a variety of disciplines.

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成年蝇blow是最早在新鲜尸体上定居的食虫性昆虫之一。他们将卵孵化成幼虫，然后以腐烂的尸体为食。像所有生物一样，苍蝇“就是他们吃的东西”，这意味着它们身体组织的同位素组成反映了他们的饮食。这个手稿联合收割机生态学通过使用同位素比率质谱仪（IRMS）来了解之间的关系的法医学应用δ ¹³在不同腐肉源氨基酸的C和吹飞上他们饲料。我们还测量了在苍蝇的每个主要生命阶段发生的氨基酸水平分级分离。成年打击来自商业的Calliphora vicina菌株（Robineau-Desvoidy）（双翅目：Calliphoridae）产于生猪肉肌肉，牛肉肌肉或鸡肝上。从每个腐肉中选择幼虫，p和成年蝇，进行氨基酸化合物特异性同位素分析。典范判别分析显示，在100％（原始规则）和96.8％（留一法交叉验证[LOOCV]）的情况下，果蝇被正确地分类为特定的腐肉类型。关于生命阶段，我们分别在原始规则和LOOCV中获得了正确分类的100％和71％。大多数必需氨基酸的同位素比率在生命阶段之间（95％CI）没有显着变化。但是，在成年阶段同位素消耗掉了一些非必需氨基酸（Ala，Ser和Glu）和一些有条件必需氨基酸（Gly和Pro）。除了必需氨基酸¹³ ℃，相对于摄食的腐肉，成年蝇蝇在¹³ ℃被消耗掉。这些结果使排除腐肉的潜在来源成为幼虫食物成为可能。氨基酸特有的IRMS可以帮助昆虫学家告知蝇蝇是刚从另一个位置到达以尸体为食还是从from为尸体的中冒出。这样的洞察力可以提高蝇blow对于尸检间隔确定的重要性。通过使用氨基酸的化合物特异性同位素分析，将生物从一个营养级连接到另一个营养级的分析能力可能会在多种学科中产生广泛的影响。

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