1. Macronutrients, comprising carbohydrates, proteins and lipids, underpin many ecological processes, but their quantification in ecological studies is often inaccurate and laborious, requiring large investments of time and bulk samples, which make individual‐level studies impossible. This study presents Macronutrient Extraction and Determination from Invertebrates (MEDI), a protocol for the direct, rapid and relatively low‐cost determination of macronutrient content from single small macroinvertebrates.
2. Macronutrients were extracted by a sequential process of soaking in 1:12 chloroform:methanol solution to remove lipid and then solubilising tissue in 0.1 M NaOH. Proteins, carbohydrates and lipids were determined by colorimetric assays from the same individual specimens.
3. The limits of detection of MEDI with the equipment and conditions used were 0.067, 0.065 and 0.006 mg/ml for proteins, carbohydrates and lipids respectively. Adjusting the volume of reagents used for extraction and determination can broaden the range of concentrations that can be detected. MEDI successfully identified taxonomic differences in macronutrient content between five insect species.
4. Macronutrient Extraction and Determination from Invertebrates can directly and rapidly determine macronutrient content in tiny (dry mass ~3 mg) and much larger individual invertebrates. Using MEDI, the total macronutrient content of over 50 macroinvertebrates can be determined within around 3 days of collection at a cost of ~$1.35 per sample.

中文翻译：

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MEDI：无脊椎动物中大量营养素的提取和测定，一种快速、廉价且简化的方案

1. 
   常量营养素包括碳水化合物、蛋白质和脂质，是许多生态过程的基础，但生态研究中的定量往往不准确且费力，需要投入大量时间和大量样本，这使得个体水平的研究变得不可能。本研究提出了无脊椎动物常量营养素提取和测定 (MEDI)，这是一种直接、快速且相对低成本测定单个小型大型无脊椎动物常量营养素含量的方案。
2. 
   通过浸泡在 1:12 氯仿:甲醇溶液中以去除脂质，然后在 0.1 M NaOH 中溶解组织的连续过程来提取常量营养素。通过比色法测定同一个体样本中的蛋白质、碳水化合物和脂质。
3. 
   在所用设备和条件下，MEDI 对蛋白质、碳水化合物和脂质的检测限分别为 0.067、0.065 和 0.006 mg/ml。调整用于提取和测定的试剂体积可以扩大可检测的浓度范围。 MEDI 成功识别了五种昆虫之间宏量营养素含量的分类差异。
4. 
   无脊椎动物中大量营养素的提取和测定可以直接快速地测定微小（干重约 3 毫克）和更大的个体无脊椎动物中的大量营养素含量。使用 MEDI，可以在收集后约 3 天内测定 50 多种大型无脊椎动物的总大量营养素含量，每个样品的成本约为 1.35 美元。