模拟干旱胁迫对稻虱缨小蜂的影响

为明确干旱胁迫对稻虱缨小蜂Anagrus nilaparvatae Pang et Wang生态适应性的影响,采用不同浓度的聚乙二醇(polyethylene glycol,PEG)6000模拟干旱生境,研究了干旱胁迫对稻虱缨小蜂生长发育、繁殖的影响,并观察了稻虱缨小蜂对感虫品种TN1和抗虫品种IR36水稻上褐飞虱Nilaparvata lugens Stl卵的选择情况。结果表明,稻虱缨小蜂幼虫的发育历期随PEG6000浓度的升高而延长;成虫寿命则随着PEG6000浓度的升高而缩短,经20%PEG6000处理7 d后雌蜂寿命最短,在TN1和IR36水稻上分别为25.1 h和25.4 h;经20%PEG6000胁迫处理7 d后,在TN1、IR36水稻上稻虱缨小蜂的平均卵寄生量最低,分别为10.9粒和8.1粒。与20%PEG6000处理相比,稻虱缨小蜂对未经干旱胁迫处理水稻上的褐飞虱卵具有明显的选择性。研究表明,模拟干旱胁迫能降低稻虱缨小蜂生态适应性,且降低对褐飞虱卵的寄生力和选择性。

Effects of simulated drought stress on the ecological fitness of Anagrus nilaparvatae Pang et Wang

To study the ecological fitness and selectivity of Anagrus nilaparvatae Pang et Wang under varied drought stress, the development of A. nilaparvatae, the selectivity and parasitic capacity of A. nilaparvatae to brown planthopper (BPH), Nilaparvata lugens Stål, on different rice varieties TN1 and IR36 simulated by polyethylene glycol 6000 (PEG6000) were determined in the laboratory. The results showed that the nymphal duration of A. nilaparvatae was obviously prolonged with the concentration of PEG6000 increasing; however, the longevity of the female adult was shortened. The longevity of female adults treated by 20% PEG6000 for seven days was the shortest among different treatments, and the shortest longevities of female adults on TN1 and IR36 were 25.1 h and 25.4 h, respectively. The parasitic capacity of A. nilaparvatae treated by 20% PEG6000 for seven days was lower than that in the other treatments, and the parasitic capacity of A. nilaparvatae on TN1 and IR36 were 10.9 and 8.1 per female, respectively. Compared with the TN1 and IR36 rice plants treated by 20% PEG6000, the female adults had significant selectivity to BPH eggs on the rice plants untreated by drought stress. The results indicated that simulated drought stress not only reduced the ecological fitness of A. nilaparvatae, but also decreased its selectivity and parasitic capacity.