Observations on the autumn migration of Nilaparvata lugens (Homoptera: Delphacidae) and other pests in East Central China
Radar, aerial netting and ground sampling were used to study the autumn migration of Nilaparvata lugens (Stål) in Jiangsu Province in east central China. Emigration of macropterous adults increased from late August until late September as the main rice crop matured and was harvested. In early and mid September, the resulting windborne migrations carried the planthoppers mainly towards the west, although the migration directions ranged (within the western sector) from south to north. By late September, however, displacements were predominantly to the south-west on the then prevailing north-east monsoon winds: migration was particularly rapid when the north-easterlies were reinforced by typhoons. Although in late September such movements to more southerly latitudes are essential for the survival of the planthoppers' progeny, we found no definite evidence for preferential emigration on winds blowing towards the south. There were, however, indications that when winds towards the north occurred, the duration of migratory flight was curtailed. Irrespective of any possible preference for migration on northerlies, a large proportion of the N. lugens population would normally be carried in an adaptive southwards direction, because the advent of the north-east monsoon occurs at a time when the number of flight-ready planthoppers approaches its peak.
Riley, J.R.; Reynolds, D.R.; Smith, A.D.; Rosenberg, L.J.; Cheng XiaNian; Zhang XiaoXi; Xu GuoMin; Cheng JiYi; Bai AiDong; Zhai BaoPing; Wang HaiKou. Observations on the autumn migration of Nilaparvata lugens (Homoptera: Delphacidae) and other pests in east central China. Bulletin of Entomological Research (1994) 84 (03) 389-402. [DOI: 10.1017/S0007485300032521]