Comparative analysis of population dynamics of the brown planthopper between the tropical and temperate region.

热带和温带不同种植制度的稻区褐飞虱种群动态基本特征有明显差异：(1)在热带同步种植区，褐飞虱种群在初代至高峰期迅速繁殖，尽管初迁种群密度较低，但常常达到破坏性水平，如温带地区所示。但在交错区和同步区的二季作物中，种群增长率和峰值种群密度都较低。寄生蜂等天敌的数量在决定季节性种群发展的这种差异方面发挥了重要作用。(2)各稻田高峰期或暴发密度可根据各季节初世代或上一季世代密度进行预测，预测精度较高。然而，在后一种情况下，种群增长速度和峰值种群密度在不同农田之间差异很大，这取决于每一农田的水分状况。(3)在前者中，由于种内竞争，只有在导致寄主植物严重恶化的高密度下才能检测到调控过程。然而，在后一阶段，调控过程在作物早期阶段的密度要低得多。长翅目成虫的密度依赖扩散对稳定田间种群波动起着重要作用。

Distinct differences in the basic features of population dynamics of the brown planthopper were detected between the different rice cropping systems in the tropical and temperate regions : (1) In the synchronous cropping area in the tropics, BPH populations multiplied rapidly in the period from initial to peak generation, reaching quite often the destructive level despite the low density of initial immigrants, as shown in the temperate regions. However, in the staggered cropping area and also in the second crops in the synchronous area, the population growth rate and the peak population density were much lower. The abundance of natural enemies such as parasitic wasps playd a major role in determining such a difference in seasonal population development. (2) The density at the peak generation or the occurrence of outbreaks in each paddy field was predictable in the formers with fairly high accuracy on the basis of the density at the initial or previous seasonal generations. In the latters, however, the rate of population growth and the peak population density widely varied among the fields depending on the water status in each field. (3) In the formers, the regulatory processes were only detected in such high densities as cause the considerable deterioration of host plant, because of intra-specific competition. However, in the latters, the regulatory processes operated at a much lower density in the earlier stages of the crops. Density-dependent dispersal of macropterous adults playd an important role to stabilize the population fluctuation among the fields.