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Four species in the genus of noctuid moths, Heliothis, are major agricultural pests throughout the world. We propose that their pest status is due, in part, to their capacity for long-range movement. This review discusses movement as an adaptive strategy in these moths, details the evidence for and against migratory movements, and evaluates techniques that can be used to investigate movement over long range.

1987). The migration of Nilaparvata lugens (stål) (delphacidae) and other hemiptera associated with rice during the dry season in the Philippines: a study using radar, visual observations, aerial netting and ground trapping. AbstractThe migratory flight behaviour of Nilaparvata lugens (Stal), other delphacid and cicadellid pests of rice and some of their heteropteran predators was investigated during the dry-season crop in an irrigated ricegrowing area of the Philippines. A combination of radar (including an X-band and a newly-developed Q-band system (8 mm wavelength)), aerial netting, ground trapping and visual observations was used to determine diel changes in aerial density and composition of arthropods in flight over the study site. The most abundant migrant caught in the aerial nets was Cyrtorhinus lividipennis Reuter (a mirid predator of N. lugens), with Nephotettix spp. and Nilaparvata lugens the next most abundant species. Flight activity in all migrants was found to be very largely confined to periods of about 30 min at dusk and dawn, with minimal activity at other times of the day and night. Migration distance in the dusk flight was generally limited to 6-30 km, depending on wind speed, and the dawn migration covered shorter distances due to the lighter winds. Small numbers of rice cicadellids and delphacids including N. lugens were occasionally detected later in the night, and these may have had the potential to migrate longer distances.

tern Australia. These migrations are interpreted as an adaptation to the geographie and climatic factors that control larval development and moth flight in this region, and especially to the erratic rainfall regime of the inland source areas. AbstractThe migrations of a number of species ofnoctuid and pvralid moths were studied with a specialpurpose radar unit and by direct sampling with a kite-borne net at a locality in central-western New South Wales during the early spring of 1980. The observations coincided with the appearance of very large numbers of moths throughout much of south-eastern Australia, and immediately followed a major caterpillar plague in south-western New South Wales.The migrations occurred mainly at night, and were most intense during periods of warm weather. Several different directions of migration were observed, but the movements were always approximately downwind; distances of a few hundred kilometres were typically covered during a single night. A number of quantitative measures of the migration intensity have been estimated for some of the flights. The migrating population frequently exhibited a degree of mutual alignment, which was sometimes in a direction different from that of the migration. Migrants became concentrated into layers at high altitudes (up to 1900 m) on two occasions during the night. Similar high-altitude migrations were also detected during daylight.It is inferred that an early spring re-invasion of drought-affected inland areas, and of areas on the continental periphery which have a cool winter climate, by means of long-distance migrations from inland areas where autumn and winter conditions have been favourable for larval development, is an almost regular feature of the population dynamics of several moth species that are of economic importance in south-eas-

Transoceanic migration of four species of macrolepidoptera to subantarctic Macquarie Island has been detected in 7 out of 33 years during the period 1962-96 and is restricted to spring and autumn. Analyses of synoptic charts during the migration period show that autumn immigrants originated from New Zealand and comprised a single species of noctuid moth, Agrotis ipsilon (Walker). Spring immigrants originated from Australia and comprised two noctuids, Dasypodia selenophora Guenée and Persectania ewingii Westwood and a butterfly, Vanessa kershawi (McCoy). Autumn migrations were associated with depressions in the southern Tasman Sea. Spring migrations were associated with the eastward passage of prefrontal airflows ahead of cold fronts which extended from southern Australia to the west of Macquarie Island. In an analysis of one of these events, winds exceeded 30 ms −1 at 300 m altitude and could have transported migrants from Tasmania to Macquarie Island overnight in less than 10 h. Flight activity was assisted by the presence of a nocturnal temperature inversion that maintained upper air temperatures above 5°C. The effect of potential global warming on the migration and colonization of Macquarie Island by insects is discussed.