通辽市科尔沁区苜蓿蓟马物种多样性及优势种发生动态

Species diversity and occurrence dynamics of dominant species of alfalfa thrips in Horqin District,Tongliao City

为明晰科尔沁区苜蓿蓟马物种多样性及其优势种发生动态,于2019、2020年的7月上旬至9月上旬对当地刈割和不刈割两个处理苜蓿样地的苜蓿蓟马进行系统研究。结果表明,当地苜蓿蓟马由2科5属8种组成,优势种为花蓟马和八节黄蓟马。多样性分析显示,同年苜蓿蓟马4种多样性指数均表现为刈割样地高于不刈割样地,且Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J)在两年均以前者显著高于后者。两个优势种发生密度动态均呈波动性变化,同一年份其发生密度动态在两个样地基本一致,同年同一调查日期其发生密度基本以不刈割样地较高。当地苜蓿蓟马优势种为害盛期集中在每年的7月中旬至8月下旬,以8月中下旬为害最重。刈割可在一定程度上降低优势种的发生密度,但对不同物种或同一物种在不同年份的影响程度不同。气象因素、刈割情况(刈割时间、次数)、天敌种类和数量、苜蓿品种等综合影响苜蓿蓟马的发生动态。

This study aimed to investigate the species diversity of alfalfa thrips and the occurrence dynamics of the dominant species in Horqin District.A systematic study was conducted in mowing and non-mowing alfalfa plots from early July to early September in 2019 and 2020.The results showed that there were 8 species of alfalfa thrips in the area,from 5 genera of 2 families,with Frankliniella intonsa and Thrips flavidulus being the dominant ones.The diversity indices of alfalfa thrips were found to be higher in the mowing plots than the non-mowing ones in the same year,with the Shannon Wiener diversity index(H′)and Pielou evenness index(J)being significantly higher in the mowing treatment in both years.The population dynamics of the two dominant species show fluctuations.In the same year,the dynamics were similar in the two plots,and on the same survey date,the abundance of dominant thrips was usually higher in the nonmowing plots.The peak damage period of alfalfa thrips in the local area was from mid-July to late August each year,with the most severe damage occurring in mid-to-late August.Mowing can reduce the abundance of dominant species,but the impact varies in species and years.Meteorological factors,mowing conditions(time and frequency),species and quantities of natural enemies,and alfalfa varieties affected the occurrence dynamics of alfalfa thrips.