摘要
对褐飞虱种群在不同含氮量稻株和若虫密度条件下的反应进行了研究。结果表明,若虫密度对褐飞虱存活的抑制作用随若虫密度提高而增强,但随寄主含氮量的增加而显著下降,表现为低含量的寄主植物可以增强对种群调节的负反馈作用。在低氮稻株上的饲养代数也明显影响若虫存活率,而在高氮稻株上饲养的不同代别褐飞虱之间则无显著差异。若虫率与稻株含氮量呈极显著的负相关,即在高若虫密度下寄主含氮量的增加可显著缩短褐飞虱若虫的发育历期。与高含氮量稻株上的褐飞虱种群相比,饲养在低含氮量稻株上的褐飞虱种群的若虫发育时间在高若虫密度下显著延长。在每盆40头褐飞虱若虫的密度下,成虫性比与稻株含氮量呈极显著的正相关,而在不同若虫密度下,随着若虫密度的增加雌性成虫比例显著下降。在每盆160头的若虫密度时低氮稻株上褐飞虱种群的性比低于0.3,显著低于在高氮稻株上的褐飞虱种群的性比0.85。在含氮量低的稻株上的雌成虫体重随若虫密度的增加极显著减少,连续取食第2代的雌成虫又比取食第1代时的轻。在所研究的所有若虫密度下,取食高含氮量稻株的褐飞虱种群的雌成虫寿命均为取食低含氮量稻株褐飞虱种群雌成虫寿命的3倍左右,差异极为显著。稻株含氮量和若虫密度对褐飞虱生殖力的作用最大,特别是在低氮稻株上若虫密度对褐飞虱生殖力的作用更为突出。在高含氮量稻株上的卵孵化率均随若虫密度的增加而有所下降,但在相同含氮量稻株上卵孵化率的差异均不显著。结果推测由于施用氮肥较多的水稻可以承受高密度的褐飞虱,提高了它们的迁出临界密度,减少了褐飞虱在克服逆境过程中的种群损失,从而造成更高的密度和更重的田间危害程度。
The brown planthopper （BPH）, Nilaparvata lugens （Still）, is an important insect pest of rice in Asia. Its importance has been attributed to the effects of “Green Revolution” which promoted intensive rice monocultures with high fertilizer and pesticide applications. Since BPH depends on rice for its existence, host plant chemistry plays a major role in the population biology of BPH. The combined effects of increased colonization and improved performance may result in rapid population growth and high densities in nitrogen enriched crops. To fully clarify the ecological mechanism of BPH outbreak on the rice plants with high nitrogen regimes, this study was emphasized on the response of BPH to high nymph density on rice plants with different nitrogen regimes and was conducted in International Rice Research Institute （IRRI）, Philippines. The results indicated that the nymph survival rates were markedly decreased with the increase of nymph density and with the reduce of nitrogen content in rice plants, implying the negative feedback mechanisms restricting population growth by both high nymph density and low quality of host plants, while lower nymph survival rates were found in the populations of BPH fed on rice plants with low nitrogen regime. The ratio of nymphs to total number of BPH was negatively related to the content of nitrogen in host plants at high nymph densities of 80 and 160 per pot, indicating the shortened nymphal development on the rice plants with high nitrogen content under high nymph densities, meanwhile significant longer nymph durations of BPH were recorded in the populations continuously fed on rice plants with low nitrogen regime compared to those on rice plants with high nitrogen regime. The ratio of female to male adults was positively related to the nitrogen content in host plants at the nymph density of 40 per pot, however, it decreased with the increase of nymph density. Female adult weight was significantly reduced with increased nymph density on rice plants with low nitrogen fertilizer. Female adult longevities on high nitrogen host plants were 3-fold longer than those on low nitrogen plants at all three tested nymph densities. Increased nitrogen content in rice plants significantly increased BPH fecundity, and the great difference in fecundity among three tested nymph densities was recorded on rice plants with low nitrogen fertilizer. Those results should suggest the application of high nitrogen fertilizer increased the load capacity of rice plants for a high BPH density.
出处
《生态学报》
CAS
CSCD
北大核心
2005年第8期1838-1843,共6页
Acta Ecologica Sinica
基金
国际水稻研究所资助项目~~
关键词
褐飞虱
水稻
氮肥
若虫密度
生长发育
生殖
brown planthopper ； rice
nitrogen fertilizer
nymphal density
growth and development
reproduction
