施用蝗虫微孢子对草原地上部分天敌群落多样性的影响

为明确蝗虫微孢子对蝗虫的持续控制,2015年在青海省开展了蝗虫微孢子防治草原蝗虫的试验和连续跟踪调查。结果表明,施用蝗虫微孢子前后温性和高寒草原蝗区天敌种类无明显变化,但部分天敌类群所占比例发生了变化,施用蝗虫微孢子2、3、4周后,温性草原中寄生蝇所占比例分别显著增加了330.6%、752.8%、752.8%,高寒草原中寄生蝇所占比例分别显著增加了108.1%、309.9%、310.8%,温性草原中芫菁所占比例分别显著下降了43.5%、45.5%、75.5%,高寒草原中芫菁所占比例分别显著下降了54.2%、77.2%、76.3%。施用蝗虫微孢子2、3和4周后,温性草原的Shannon指数比防治前分别显著增加了5.7%、7.0%、3.8%,Pielou指数比防治前分别显著增加了6.2%、6.2%、3.7%,Simpson指数比防治前分别显著增加了5.4%、6.8%、4.1%;施用蝗虫微孢子2周后,高寒草原的Shannon指数、Pielou指数和Simpson指数比防治前分别显著升高了4.8%、5.4%、3.8%,施用3周后,3个天敌群落多样性指数比防治前分别增加了1.8%、1.3%、2.2%,但Shannon指数和Simpson指数与防治前无显著差异,而Pielou指数比防治前显著增加,施用4周后,3个指数均与防治前无显著差异。施用蝗虫微孢子2、3和4周后,天敌群落布雷柯蒂斯距离与防治前差异显著,而重复样区间的布雷柯蒂斯距离在整个调查期无显著变化。表明蝗虫微孢子施用后对不同生态类型草原天敌群落多样性有一定的保护作用。

Effects of microsporidia Paranosema locustae on the community structure and diversity of aboveground natural enemies of grasshoppers in rangelands

For sustainable control of grasshoppers by microsporidia Paranosema locustae, the effects of P. locustae on grasshoppers were investigated in Qinghai Province in 2015. The results showed that there was no significant difference in the species of natural enemies in temperate and alpine steppe before and after treatment with P. locustae, but the ratios of natural enemies were different. After treating P. locustae for two, three, or four weeks, the ratio of the parasitic flies from the temperate steppe increased by 330.6%, 752.8%, 752.8%, and those from the alpine steppe increased by 108.1%, 309.9%, 310.8%, while the ratio of blister beetles from the temperate steppe decreased by 43.5%, 45.5%, 75.5%, and those from the alpine steppe decreased by 54.2%, 77.2%, 76.3%, respectively. The Shannon index of natural enemies increased by 5.7%, 7.0%, 3.8%; the Pielou index increased by 6.2%, 6.2%, 3.7%,and the Simpson index increased by 5.4%, 6.8%, 4.1% after treating P. locustae for two, three, or four weeks in the temperate steppe, respectively. In the alpine steppe, the Shannon, Pielou and Simpson indexes increased by 4.8%, 5.4%, and 3.8%, respectively, two weeks after treatment; the Shannon and Simpson indexes non-significantly increased by 1.8% and 2.2%, respectively, and the Pielou index significantly increased by 1.3% after treatment for three weeks, but the three indexes showed no significant changes post treatment for four weeks. The Bray-Curtis distances of the community of natural enemies showed significant difference after treatment with P. locustae for two, three, or four weeks, but within the replicates no significant change was observed. These results suggested that P. locustae had no sideeffects on the community diversity of natural enemies in the temperate and alpine steppes after treatment with P. locustae.