【目的】 昆虫肠道微生物对于其食物消化、生长发育以及环境适应性等方面都具有重要作用，本研究旨在探究小菜蛾Plutella xylostella (L.)溴氰菊酯敏感和抗性品系幼虫肠道微生物群落的功能多样性。【方法】 采用Biolog-ECO技术对两品系小菜蛾1-4龄幼虫的肠道样品进行分析。【结果】 小菜蛾溴氰菊酯敏感和抗性品系的低龄幼虫肠道微生物的代谢活性（AWCD）均高于高龄幼虫，两品系同龄幼虫肠道样品代谢活性类似。两品系样品均能代谢30种供试碳源，均不能代谢羧酸类的2-羟基苯甲酸。敏感品系样品的Shannon指数和Mclntosh指数均高于抗性品系。敏感品系1-3龄幼虫肠道样品的Shannon指数类似，且均高于该品系4龄样品；抗性品系1-4龄幼虫肠道样品的Shannon指数逐渐减小。两品系McIntosh指数均为1龄幼虫的最高，2-4龄的相当。【结论】 小菜蛾低龄幼虫肠道微生物的生理活性均高于高龄幼虫，同时小菜蛾溴氰菊酯敏感和抗性品系幼虫的肠道微生物在功能多样性上存在差异。

[Objectives]  The gut microbiota of insect play an important role in food digestion, development and environmental adaptation. This study aims to compare the functional diversity of the gut microbial communities of deltamethrin-resistant and -sensitive diamondback moth larvae. [Methods]  Gut samples from 1^st to 4^th instar larvae of deltamethrin-resistant and -sensitive diamondback moths were analyzed with Biolog-ECO. [Results]  AWCD values from younger instar larvae were all higher than those of older larvae and AWCD values for larvae of the same age were nearly identical. Thirty tested carbon substrates were metabolized by all gut samples with the exception of the carboxylic acid substrate 2-Hydroxy benzoic acid. The Shannon and McIntosh indices of sensitive larvae were higher than those of the resistant larvae. The Shannon indices of 1^st to 3^rd instar sensitive larvae were nearly the same, and were higher than that of 4^th instar larvae. Resistant larvae could be ranked in terms of the Shannon index as follows: 1^st instar> 2^nd instar>3rd instar>4^th instar. In both sensitive and resistant larvae, the gut microbial McIntosh index was highest in the 1^st instar, with 2^nd to 4^th instars having similar McIntosh index values. [Conclusion]  The physiological activity of larval gut microorganisms in younger larval instars was higher than that in older instars. The functional diversity of the gut microbial community differed between deltamethrin-resistant and -sensitive diamondback moth larvae.