Weather associated with spring and summer migrations of rice pests and other insects in south-eastern and Eastern Asia

Abstract

Trajectory analysis of the windfields at 10 m and 1.5 km was used to determine the direction and extent of windborne movements of insects trapped in spring and summer in south-eastern and eastern Asia for the period 1968 to 1985. Approximately 2500 trajectories, depicting the movements of airborne particles, were constructed where temperatures were high enough (>=10°C) to allow flight and where wind speeds (> =5 kmh−1) were expected to lead to downwind displacements. Trap catches were dominated (97%) by delphacid species (e.g. Nilaparvata lugens Stål and Sogatella furcifera (Horváth)), with Cicadellidae (1.1%) and Diptera (0.7%) as the next most numerous. Very few Lepidoptera were reported. Most trajectories were less than or equal to 40 h in duration. The previously recognized northwards migration along a broad front in prevailing Summer Monsoon and Trade winds was confirmed, as was the important role of frontal depressions in the windborne migration of insects in temperate areas. Nearly 50% of the trajectories were constructed in mobile weather systems which both disturbed and strengthened the prevailing winds and led to pronounced differences in the direction and distance of sources for insects caught at any catching site. Similarly, fluctuations in position of quasi-stationary fronts induced considerable mixing of populations from different sources and influenced the northern extent of each phase of rice pest migration. The results supported earlier findings that migrations occurred between the tropics and temperate areas during the spring and summer, but also indicated that migrations within the tropics at this time of year were a more frequent occurrence than had been considered previously.

A migration analysis of the rice planthopper Nilaparvata lugens from the Philippines to East Asia with three‐dimensional computer simulations

“…The long-term migration analysis suggested that early migrations from the Philippines to southern China were likely to have occurred. Early migrations observed on ships off the coast of Guangdong province from March to June 1984 were analyzed by two-dimensional trajectory analysis, and their source was found to be the Philippines (Mills et al 1996). In addition, it is known that planthoppers emerge year-round in the Philippines because of its tropical climate.…”

Variation of pre‐ovipositional period in the brown planthopper, Nilaparvata lugens, collected in tropical, subtropical and temperate Asia

“…After a series of northward expansions from the source through a few generations, N. lugens invade East Asia (Cheng et al 1979;Sogawa and Watanabe 1992;Zhou et al 1995). Weather associated with these spring and summer migrations of N. lugens are often analysed by many workers (Watanabe and Seino 1991;Kisimoto and Sogawa 1995;Mills et al 1996;Turner et al 1999;Otuka et al 2005b). A hypothesis of autumn return migration from temperate China to hibernating areas was also proposed by Cheng et al (1979).…”

“…1995). Weather associated with these spring and summer migrations of N. lugens are often analysed by many workers (Watanabe and Seino 1991; Kisimoto and Sogawa 1995; Mills et al. 1996; Turner et al.…”

Starvation tolerance of macropter brown planthopper, Nilaparvata lugens, from temperate, subtropical, and tropical populations in East and South‐East Asia

“…After a series of northward expansions over a few generations, N. lugens invades as far as temperate East Asia (Cheng et al, 1979;Sogawa & Watanabe, 1992;Zhou et al, 1995). There have been many reports on the association between weather and spring and summer migrations of N. lugens (Watanabe et al, 1991;Kisimoto & Sogawa, 1995;Mills et al, 1996;Turner et al, 1999;Otuka et al, 2005Otuka et al, , 2006. Cheng et al (1979) proposed an autumn return migration from temperate China to hibernating areas, which has been supported by the detection of the southwestward mass movement of the planthopper by radar observations (Riley et al, 1991(Riley et al, , 1994 and weather analysis (Rutter et al, 1998).…”