安阳棉蚜寄主专化型及其形成机制初步分析

Host Biotypes of Cotton Aphid Aphis gossypii Glover and Preliminary Analysis of the Formation Mechanism in Anyang Region of China

为了解安阳地区棉蚜寄主专化型情况,进行了棉蚜不同寄主转接的适合度测定。结果显示,棉花上与黄瓜上的棉蚜相互转接后其存活率及繁殖力均明显下降,不能建立种群;棉花上的棉蚜转接到西葫芦上时,其存活率及繁殖力与其原寄主无显著差异;黄瓜上的棉蚜转接到西葫芦上时,其净增殖率及内禀增长率均显著地高于其原寄主;黄瓜上棉蚜对西葫芦的适应性比棉花上棉蚜强。表明安阳地区棉蚜存在黄瓜和棉花两种寄主专化型,且都可以利用西葫芦。进一步对3种植物苗期叶片游离氨基酸进行测定,结果显示,游离氨基酸种类及总量均在西葫芦中最多,棉花中次之,黄瓜中最少。寄主植物游离氨基酸种类及含量的多少会影响棉蚜的生长与繁殖,可能是棉蚜寄主专化型形成的影响因素之一。

To better understand cotton aphid host biotypes in Anyang region of China, we assessed cotton aphid fitness upon transplantation to different host plants. Results showed that the survival and fecundity of cotton aphid declined dramatically and population could not be established when the host plants of cotton aphid were exchanged. There were no significant differences in aphid net reproductive rate, intrinsic rate of increase and average generation time when transferred to zucchini leaves when compared with the original cotton leaves, while net reproductive rate and intrinsic rate of increase on zucchini leaves were higher than the host cucumber leaves. However, aphids from cucumber plants had greater fitness when transplanted to zucchini leaves than those from cotton plants, the intrinsic rate of increase was 0.41 for the aphids transplanted from cucumber plants and 0.34 for the aphids transplanted from cotton plants. In addition, free amino acids in cotton, cucumber and zucchini leaves were determined at the seedling stage. Amino acid types and total free amino acid content were most abundant in zucchini, followed by cotton, then cucumber. These data suggest that there are two biotypes in Anyang region, a cotton biotype and a cucumber biotype, yet both can survive on zucchini plants. Furthermore, free amino acid types and content may affect growth and reproduction of cotton aphid, thus promoting host biotype formation.