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China is the world's second-largest maize producer and consumer. In recent years, the invasive fall armyworm Spodoptera frugiperda (J.E. Smith) has adversely affected maize productivity and compromised food security. To mitigate pest-inflicted food shortages, China's Government issued biosafety certificates for two genetically modified (GM) Bt maize hybrids, Bt-Cry1Ab DBN9936 and Bt-Cry1Ab/Cry2Aj Ruifeng 125, in 2019. Here, we quantitatively assess the impact of both Bt maize hybrids on pest feeding damage, crop yield and food safety throughout China's maize belt. Without a need to resort to synthetic insecticides, Bt maize could mitigate lepidopteran pest pressure by 61.9-97.3%, avoid yield loss by 16.4-21.3% (range -11.9-99.2%) and lower mycotoxin contamination by 85.5-95.5% as compared to the prevailing non-Bt hybrids. Yield loss avoidance varied considerably between experimental sites and years, as mediated by on-site infestation pressure and pest identity. For either seed mixtures or block refuge arrangements, pest pressure was kept below established thresholds at 90% Bt maize coverage in Yunnan (where S. frugiperda was the dominant species) and 70% Bt maize coverage in other sites dominated by Helicoverpa armigera (Hübner) and Ostrinia furnacalis (Guenée). Drawing on experiences from other crop/pest systems, Bt maize in se can provide area-wide pest management and thus, contribute to a progressive phase-down of chemical pesticide use. Hence, when consciously paired with agroecological and biodiversity-based measures, GM insecticidal crops can ensure food and nutrition security, contribute to the sustainable intensification of China's agriculture and reduce food systems' environmental footprint.

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 fall armyworm (FAW), Spodoptera frugiperda is one of the most damaging crop pests, and it has become major threat to the food security of many countries. In order to monitor possible invasion of this pest into China, a searchlight trap was established in March 2018 in western Yunnan Province, China, where it has served as the “first station” for many pests that have migrated from Myanmar to China. A number of suspected FAW moths were captured and identified by DNA sequencing. The results showed that the FAW moth was first captured on December 11 and formed its first immigration peak in mid-December 2018. DNA detection revealed that the early invading FAW population was the “corn-strain”. The field survey indicated that the pest mainly colonized corn in Pu'er, Dehong and Baoshan areas. Migration trajectory simulation implied that the moths might have mainly come from the eastern area in the mid-latitude region of Myanmar (20–25°N, 94–100°E). This case study confirmed the first immigration of FAW into China, and will be helpful for guiding monitoring and management work to control this pest.

The fall armyworm (FAW, Lepidoptera: Noctuidae), Spodoptera frugiperda (J. E. Smith), invaded China in mid-December 2018; since then, it has become a great threat to Chinese agricultural production. Qinling Mountains–Huaihe River region (QM–HRR) is the transitional zone between northern and southern China, an important region for both corn and wheat production. Based on the actual occurrence of QM–HRR invaded by FAW in 2019, daily mean surface air temperature and nocturnal wind conditions at 925 hPa were examined, and migratory routes of FAW moths originated in QM–HRR were modeled by a forward-trajectory-analysis approach. The results indicated that migratory activities of FAW adults emerged in QM–HRR were initiated from late June. The moths from western QM–HRR, where has complex topographic terrain, mainly flied to Ningxia and Inner Mongolia before mid September. However, FAW moths from the eastern QM–HRR primarily engaged in high-altitude northward transport assisted by the prevailing southerly winds before mid August, and the North China Plain was identified as the main destination of FAW. Meanwhile, the migration trajectories of FAW moths had a possibility to reach the Northeast China Plain. From mid August, FAW moths in eastern QM–HRR largely migrated southward and returned to the Yangtze River Valley. This study provides detailed information on the occurrence and migration routes of FAW moths from QM–HRR and will be helpful for early warning and development of integrated pest management strategies for the control of this exotic insect 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 clover cutworm, Scotogramma trifolii Rottemberg (Lepidoptera: Noctuidae), is a serious polyphagous insect pest of Triticum aestivum Linnaeus, Zea mays Linnaeus, Gossypium herbaceum Linnaeus, and cruciferous vegetables in Asia and Europe. Although S. trifolii has been documented as a long-distance migratory species, the seasonal pattern of migration and the mating status associated with migration in this species have not been fully understood. In this paper, a set of multi-year monitoring data concerning S. trifolii migration was reported. The monitoring study was conducted by searchlight trapping on a small isolated island at the center of the Bohai Strait in northern China in 2003–2015. Data analyses showed that there were significant seasonal differences in the migration of S. trifolii moths across the sea, in which the expected numbers of moths caught per day in July through September were much higher than in the rest of months. The percentage of trapped moths was significantly female biased. The vast majority of females trapped in August and September were virgins, with little or no ovarian development. In contrast, most females trapped in May to July had mated and been sexually mature. The results suggest that S. trifolii migrates toward the north in prevailing southerly winds during late-spring (May) and early-summer (June and July), and returns to the south in prevailing northerly winds during late-summer and early-autumn. These findings may help improve the regional forecast and management of S. trifolii.

Long non-coding RNAs (lncRNAs) are of particular interest because of their contributions to many biological processes. Here, we present the genome-wide identification and characterization of putative lncRNAs in a global insect pest, Plutella xylostella. A total of 8096 lncRNAs were identified and classified into three groups. The average length of exons in lncRNAs was longer than that in coding genes and the GC content was lower than that in mRNAs. Most lncRNAs were flanked by canonical splice sites, similar to mRNAs. Expression profiling identified 114 differentially expressed lncRNAs during the DBM development and found that majority were temporally specific. While the biological functions of lncRNAs remain uncharacterized, many are microRNA precursors or competing endogenous RNAs involved in micro-RNA regulatory pathways. This work provides a valuable resource for further studies on molecular bases for development of DBM and lay the foundation for discovery of lncRNA functions in P. xylostella.

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.

To evaluate the effect of isogeneic CD4+CD25+ regulatory T cells on cardiac allograft tolerance in heterotopic heart transplant from Balb/c to C57BL/6 mice.Isogeneic and allogeneic CD4+CD25+ regulatory T cells were obtained from pregnant C57BL/6 mice crossed with male Balb/c mice and from regular Balb/c mice. Recipient C57BL/6 mice were treated with sublethal radiation (2 Gy) and an infusion of isogeneic CD4+CD25+ regulatory T cells, allogeneic CD4+CD25+ regulatory T cells, or phosphate-buffered saline alone 1 day before a Balb/c-to-C57BL/6 heterotopic heart transplant. At 10 days after the transplant, cardiac allografts and the sera of recipients were evaluated with histology and cytokine analysis. Splenocytes of recipients were collected to determine chimerism on the day of the cessation of allograft heartbeat.Mice that received an infusion of isogeneic CD4+CD25+ regulatory T cells had significantly greater mean median survival time, greater degree of chimerism, decreased levels of cytokines (monokine induced by interferon-γ, interleukin 6, interleukin 10, and regulated upon activation, normal T cell expressed and secreted protein), and decreased lymphocytic infiltration than did mice that received phosphate-buffered saline alone. The effects on allograft tolerance were stronger in mice that received the isogeneic than the allogeneic CD4+CD25+ regulatory T cells.Isogeneic CD4+CD25+ regulatory T cells may establish cardiac allograft tolerance by inducing mixed chimerism and suppressing immune responses. Infusion with isogeneic CD4+CD25+ regulatory T cells combined with radiation (sublethal dose, 2 Gy) may establish allograft tolerance in mice. Therefore, further study is warranted because isogeneic CD4+CD25+ regulatory T cells may have therapeutic benefits.