中文摘要：

利用mt DNA COI基因序列对采自我国7个地理种群的甜菜夜蛾（Spodoptera exigua Hübner）遗传多样性与种群扩张历史进行研究。结果表明,比对206条序列（序列长度为547 bp）,共发现8个变异位点,定义5个单倍型,其中包括3个共享单倍型和2个独有单倍型;群体遗传多样性较低（Hd=0.320,π=0.000 70,Kxy=0.383）。群体间存在一定的遗传分化（FST=0.398）、基因流水平较低（Nm=0.378）。AMOVA分析表明,甜菜夜蛾遗传变异主要来自种群内,种群间变异水平较低。中性检验（Tajima’s D=-1.576,P〈0.05;Fu and Li′s F=-3.834,P〈0.05）与错配分布分析表明,我国北方甜菜夜蛾种群曾经历种群近期扩张。

英文摘要：

Mt DNA COI gene sequences collected from the 7 geographic populations of Spodoptera exigua Hübner in China was used to study the genetic diversity and population expansion in history. The results showed that a total of 8 substitution sites were detected from 206 sequences（sequence length was 547 bp）, identified 5 haplotypes from which including 3 shared hapolotypes and 2 unique hapolotypes. Population genetic diversity was lower（Hd=0.320,π=0.000 70,Kxy=0.383）. There was a certain genetic differentiation（FST=0.398） and little gene flow（Nm=0.378） between different geographic populations. The analysis of molecular variance（AMOVA） showed that the genetic variation come mainly from population, and variation within a population was greater than that between the populations. The neutral test（Tajima＇s D =-1.576,P 0.05;Fu and Li′ s F =-3.834,P〈0.05） and unimodal mismatch distribution indicated that S. exigua Hübner experienced recent population expansion in North China.