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The Asian corn borer, Ostrinia furnacalis, is the most notorious corn pest in East Asia and Oceania. The larvae seriously damage crops and lower yields. A previous study found that the O. furnacalis can migrate seasonally. However, the influencing factor on the flight performance of this pest has not yet been investigated. Here, the flight performance and its influencing factors of O. furnacalis were tested using computer-monitored flight mills. The results showed that the longest total flight of an individual was 71.49 km with a mean speed of 6.36 km·h−1 (1.77 m·s−1). Flight performance reached the peak when the moths were 2-days old, with a mean flight distance of 18.89 ± 2.03 km, mean flight duration of 7.34 ± 0.62 h and mean flight speed of 2.47 ± 0.10 km·h−1 (0.69 m·s−1). The flight capability of females was always higher than that of males. Mating status and nutritional status affected partial flight variables. For both sexes, only temperature and relative humidity among the abiotic factors significantly involved flight performance, which was most significant at 25–30 °C and 55–65%. Our study demonstrated that O. furnacalis have a high capability for migration and determined the influencing factors on flight performance. These results provide essential information for forecasting and management of this pest.

The Asian corn borer, Ostrinia furnacalis (Guenée), is a notorious pest of maize that migrates seasonally in Asia. Two migration peaks were found on Beihuang island in the Bohai Strait of China by observing the number of migrants. However, the origins and host plants of the migrants in the two migration periods remain unclear. Here, stable hydrogen (δ2H) and carbon (δ13C) isotope levels were measured to infer the origin and host plants of the O. furnacalis captured on Beihuang island in 2017–2019. δ2H in wings of spring-summer O. furnacalis captured from May to June ranged from −99 to −56‰, while that of autumn migrants from August to September ranged from −127 to −81‰. Based on the linear relationship between δ2H in the wing of migrants (δ2Hw) and δ2H in precipitation (δ2Hp), the spring-summer O. furnacalis likely originated from the summer maize area in the Huang-Huai-Hai Plain in China. In contrast, the autumn migrants came from the northern spring maize area in Liaoning, Jilin and Inner Mongolia. Based on δ13C, the spring-summer migrants fed on both C3 plants such as wheat (47.76%) and C4 weeds or belonged to the over winter individuals in maize field (52.24%), while the autumn migrants mainly fed on maize (C4, 91.21%). The results point to a northward migration in spring-summer and southward migration in autumn of O. furnacalis. Our study gives an important knowledge for improving the forecasting and management level of this pest.

Many lepidopteran species rely upon active flight to migrate over long distances, thus pursuing ephemeral resources, colonizing new habitats, or escaping adverse meteorological conditions. Though their biology and ecology are often well studied, there is only scant information on their wingbeat frequency (WBF), a key aerodynamic determinant of insect flight. In this study, we assessed interspecific and seasonal variability in WBF for 85 different migratory species of Lepidoptera (11 families) under the laboratory conditions of 25 ± 1°C and 75 ± 5% RH. WBF of migrant individuals ranged between 6.7 and 84.5 Hz and substantial interspecific differences were recorded, with members of the Bombycidae exhibiting the highest mean WBFs (i.e., 55.1 ± 1.0 Hz) and Saturniidae the lowest (8.5 ± 0.2 Hz). At a species level, seasonal variation was observed in WBF for Mythimna separata (Walker) (Lepidoptera: Noctuidae), Scotogramma trifolii Rottemberg (Lepidoptera: Noctuidae), and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Our findings add to the scientific knowledge on flight biology of migratory insects, facilitate (automatic) monitoring and population forecasting, and can have broader implications for insect pest management or biodiversity conservation.

Vast numbers of insects annually engage in trans-latitudinal migration and thereby impact structure and functioning of natural and man-made ecosystems. In eastern Asia, long-distance migration has historically been studied for single insect species rather than diverse species complexes. Here, we assessed migration dynamics of multiple economically important migratory species on an island in the Bohai Strait, China. Drawing upon 15-year trapping records of > 2.5 million specimens, we unveil inter- and intra-annual shifts in the species composition and abundance of migrant individuals. Migrants belonged to 9 orders and 36 families, primarily consisting of Lepidoptera (79% individuals), Odonata (8%), and Coleoptera (4%). Seven crop-feeding noctuids, e.g.,Helicoverpa armigera(Hübner),Mythimna separata(Walker), represented 54% of the total trapping records. Trap catches exhibited marked seasonal variation, with the highest capture rate during early fall. Yearly abundance of migratory noctuids was coupled with that of their associated natural enemies. Although overall trap catches did not decrease over the monitoring period, the entire order of Odonata experienced a 14.1% annual rate of decline. Furthermore, 19 out of 108 species exhibited a progressively declining abundance over time, including the cosmopolitan cutwormAgrotis ipsilon(Hufnagel) and the insectivorous dragonflyPantala flavescensFabricius. Our work provides unprecedented insights into insect migration dynamics in eastern Asia, helps fine-tune forecasting and early-warning systems of crop pests, and thereby guides integrated pest management within local agro-landscapes. Also, a long-term tracking of migrant insect populations can shine light on the fate of (insect-mediated) ecosystem services and trophic dynamic processes at a macroscale.

The fall armyworm (FAW), native to the Americas, has rapidly invaded the whole of Southern China since January 2019. In addition, it can survive and breed in the key maize- and rice- growing area of the Yangtze River Valley. Furthermore, this pest is also likely to continue infiltrating other cropping regions in China, where food security is facing a severe threat. To understand the potential infestation area of newly-invaded FAW from the Yangtze River Valley, we simulated and predicted the possible flight pathways and range of the populations using a numerical trajectory modelling method combining meteorological data and self-powered flight behavior parameters of FAW. Our results indicate that the emigration of the first and second generations of newly-invaded FAW initiating from the Yangtze River Valley started on 20 May 2019 and ended on 30 July 2019. The spread of migratory FAW benefitted from transport on the southerly summer monsoon so that FAW emigrants from the Yangtze River Valley can reach northern China. The maize-cropping areas of Northeastern China, the Korean Peninsula and Japan are at a high risk. This study provides a basis for early warning and a broad picture of FAW migration from the Yangtze River Valley.

The fall armyworm (FAW), native to the Americas, has rapidly invaded the whole of Southern China since January 2019. In addition, it can survive and breed in the key maize- and rice- growing area of the Yangtze River Valley. Furthermore, this pest is also likely to continue infiltrating other cropping regions in China, where food security is facing a severe threat. To understand the potential infestation area of newly-invaded FAW from the Yangtze River Valley, we simulated and predicted the possible flight pathways and range of the populations using a numerical trajectory modelling method combining meteorological data and self-powered flight behavior parameters of FAW. Our results indicate that the emigration of the first and second generations of newly-invaded FAW initiating from the Yangtze River Valley started on 20 May 2019 and ended on 30 July 2019. The spread of migratory FAW benefitted from transport on the southerly summer monsoon so that FAW emigrants from the Yangtze River Valley can reach northern China. The maize-cropping areas of Northeastern China, the Korean Peninsula and Japan are at a high risk. This study provides a basis for early warning and a broad picture of FAW migration from the Yangtze River Valley.

The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), is a notorious polyphagous insect pest in China and other regions of East Asia. The long-distance flight behavior of the ACB moths, however, is not well understood, especially in the field conditions. In this study, nightly monitoring data for multiple years (2003–2017) on the long-distance flight of adults crossing the Bohai Strait in northern China, showed that a large number of the adults frequently flew across the Bohai Strait from May to September with the peak migrations usually occurred, followed in order by September, June, July, and May, and the number of southward migrants was larger than that of northward migrants. From May to September in 2010, 2011, and 2017, a subsample of trapped ACB females was dissected (879 individuals in 2010, 197 individuals in 2011, and 247 individuals in 2017), and the results showed that the sex ratio of the trapped ACB moths was unbiased each month from May to September. While the proportion of mated females in northward populations (May to July = 92.85 ± 4.86%) was significantly higher than that in southward population (August and September = 74.53 ± 8.55%) . The seasonal pattern in the proportion of sexually mature females was similar to the above proportion of mated females. We conclude that the ACBs have a strong propensity and ability for long-distance migration, although local dispersal is generally considered to be the primary movement of the ACB. These findings may be helpful to improve the forecasting systems and the pest management schemes for the ACBs.