Changing patterns of the East Asian monsoon drive shifts in migration and abundance of a globally important rice pest

Numerous insects including pests and beneficial species undertake windborne migrations over hundreds of kilometers. In East Asia, climate-induced changes in large-scale atmospheric circulation systems are affecting wind-fields and precipitation zones and these, in turn, are changing migration patterns. We examined the consequences in a serious rice pest, the brown planthopper (BPH, Nilaparvata lugens) in East China. BPH cannot overwinter in temperate East Asia, and infestations there are initiated by several waves of windborne spring or summer migrants originating from tropical areas in Indochina. The East Asian summer monsoon, characterized by abundant rainfall and southerly winds, is of critical importance for these northward movements. We analyzed a 42-year dataset of meteorological parameters and catches of BPH from a standardized network of 341 light-traps in South and East China. We show that south of the Yangtze River during summer, southwesterly winds have weakened and rainfall increased, while the summer precipitation has decreased further north on the Jianghuai Plain. Together, these changes have resulted in shorter migratory journeys for BPH leaving South China. As a result, pest outbreaks of BPH in the key rice-growing area of the Lower Yangtze River Valley (LYRV) have declined since 2001. We show that these changes to the East Asian summer monsoon weather parameters are driven by shifts in the position and intensity of the Western Pacific subtropical high (WPSH) system that have occurred during the last 20 years. As a result, the relationship between WPSH intensity and BPH immigration that was previously used to predict the size of the immigration to the LYRV has now broken down. Our results demonstrate that migration patterns of a serious rice pest have shifted in response to the climate-induced changes in precipitation and wind pattern, with significant consequences for the population management of migratory pests.     

基于两种轨迹模型的褐飞虱迁飞轨迹比较研究

异地预测是迁飞性害虫发生预测的重要内容,迁飞轨迹模拟和预测是能较好地反映害虫迁飞时空动态的一种异地预测方法。褐飞虱作为我国水稻生产上的一种重要迁飞性害虫,其迁飞轨迹的准确预报,可为其灾变预警和有效防控提供科学依据。为了比较选择一些准确性好、分辨率高、易于推广应用的害虫迁飞轨迹模型,选取2006年7月初发生在湖南省洪江市的一次褐飞虱重大北迁过程作为典型个例,运用中尺度天气研究和预报模式WRF,结合NCEP气象再分析数据,利用HYSPLIT和FLEXPART两种轨迹计算模式对褐飞虱迁飞轨迹进行模拟,并验证模型模拟和计算的准确度和精确度。研究结果表明:(1)WRF-HYSPLIT和WRF-FLEXPART两种轨迹计算模式在虫源地、迁飞路径(迁飞方位角和走向)、迁飞高度、迁飞速率和迁飞距离计算上总体趋势一致,但存在一定的差异,后者的起伏变化大于前者。(2)尽管两种耦合模式在调用WRF模式输出的预报场物理变量方面有很多相同之处,但WRF-FLEXPART耦合模式在运行计算过程中比WRF-HYSPLIT耦合模式多考虑了对流参数、地表胁迫和各种地形参数,因而能更全面地反映中尺度天气过程(特别是对流性天气过程)对昆虫起飞、空中飞行和降落的动力作用,也能更真实地反映地表物理过程、大气湍流结构和地形起伏对褐飞虱种群迁飞的影响。(3)从褐飞虱种群对生境和取食条件选择上看,两种模式模拟的各高度迁入种群的虫源区、迁飞路径和降落地都是合理的、准确的。但从褐飞虱迁出、空中飞行和降落所处的三维流场来看,WRF-FLEXPART模式轨迹走向与盛行气流方向的吻合度要明显高于WRF-HYSPLIT模式。(4)两种模式均可作为业务工具在迁飞性害虫测报中推广应用。     

云南省褐飞虱早期迁入虫源及其发生大气背景分析

为了探明我国西南稻区褐飞虱早期迁入种群的虫源地,为后期预测和防治提供依据,通过对2007—2016年云南植保站4—5月份褐飞虱虫情进行分析,选取出云南省勐海、芒市、江城、师宗、麻栗坡、广南6个代表性站点,利用WRF-FlexPart耦合模式对2013年、2015年和2016年这些站点的早期迁入峰进行了数值模拟,得到近年来云南省褐飞虱早期迁入虫源的虫源地。选取了2013年褐飞虱早期迁入量较大的迁入峰进行了大气背景分析,结合峰期影响褐飞虱迁飞的大气动力场、温度场和相对湿度场,探讨了影响云南省褐飞虱早期迁入的大气背景。研究结果表明:(1)近年来云南省褐飞虱迁入的虫源主要来自缅甸,部分来自老挝和泰国,少数来自越南,还有极少量来自孟加拉国。(2)这一时期,当释放高度分别为1500、2000 m时,褐飞虱的迁飞高度分别集中在2216 m和2489 m,平均迁飞高度分别是2167、2454 m,从不同释放高度回推的褐飞虱迁飞高度的起伏趋势具有较好的一致性,表明模式能较好地反映系统性垂直气流和下垫面起伏对其上层三维流场和种群迁飞的影响。(3)选取2013年5月22—26日发生在云南勐海、麻栗坡和广南的一次典型褐飞虱迁入过程,分析了大气背景场对褐飞虱迁飞的影响,结果显示:受印缅低压控制或影响,高空从境外虫源区至云南降虫区有西南水平气流作为种群输送动力;温场在降虫区东北侧有"低温屏障墙"存在,阻止了种群的继续北迁;垂直速度场上虫源区有上升气流促使种群起飞迁出,降虫区有下沉气流促使种群降落;弱降水形成的拖曳下沉气流对降虫也十分有利;相对湿度场对此次迁飞过程不形成任何胁迫。     

Reemerging vivax malaria: changing patterns of annual incidence and control programs in the Republic of Korea

Changing patterns of the reemerging Plasmodium vivax malaria in the Republic of Korea (South Korea) during the period 1993 to 2005 are briefly analyzed with emphasis on the control measures used and the effects of meteorological and entomological factors. Data were obtained from the Communicable Diseases Monthly Reports published by the Korea Center for Disease Control and Prevention, and webpages of World Health Organization and United Nations. Meteorological data of Kangwon-do (Province) were obtained from local weather stations. After its first reemergence in 1993, the prevalence of malaria increased exponentially, peaking in 2000, and then decreased. In total, 21,419 cases were reported between 1993 and 2005 in South Korea. In North Korea, a total of 916,225 cases were reported between 1999 and 2004. The occurrence of malaria in high risk areas of South Korea was significantly (P > 0.05) correlated with the mosquito population but not with temperature and rainfall. Control programs, including early case detection and treatment, mass chemoprophylaxis of soldiers, and international financial aids to North Korea for malaria control have been instituted. The situation of the reemerging vivax malaria in the Republic of Korea is remarkably improving during the recent years, at least in part, due to the control activities undertaken in South and North Korea.     

2010年牧区2代草地螟成虫迁飞的虫源分析

草地螟(Loxostege sticticalis L.)是危害我国北方农牧区的重要迁飞性害虫,明确其迁飞、扩散规律以及与境外虫源交流情况,对早期预警和有效防治具有重要意义。2010年6月1日至9月17日,利用垂直监测昆虫雷达的观测资料,结合探照灯和地面灯灯诱虫情、迁飞高峰期雌虫卵巢解剖、区域大气环流形势和迁飞轨迹分析,在内蒙古锡林浩特西郊研究了牧区2代草地螟的迁飞过程,结果表明:2010年牧区2代草地螟迁飞高峰期出现在2010年8月8日至8月21日,高峰日为8月11日,高峰日探照灯诱虫量达9167头,卵巢发育级别以1—2级为主,高峰日雷达回波主要集中在300—400 m。轨迹分析显示:迁飞高峰期8月8日、8月10—12日牧区草地螟迁飞虫源主要来自蒙古共和国东南部及中蒙边境地区,由蒙古气旋西南侧的西北气流输送进入我国内蒙古锡林郭勒盟,再随西南气流迁入呼伦贝尔草原。     

Agamermis unka (Mermithidae) Parasitism of Nilaparvata lugens in Rice Fields in Korea

The mermithid Agamermis unka, a parasite of the brown planthopper (BPH), was found in many rice paddies in Gyeongnam Province, Korea. Nematode parasitism of adult BPH varied from year to year, reaching as high as 50% in paddies not treated with an insecticide. Parasitism was lower in insecticide-treated paddies. Generally, mermithid parasitism was higher in BPH adults collected from the lower part (19%) compared with adults collected from the upper part (8%) of the rice plant and in brachypterous (57%) compared with macropterous forms (8%). No difference in parasitism between first (54%) and second (57%) generation was observed.     

Gene Flow between the Korean Peninsula and Its Neighboring Countries

SNP markers provide the primary data for population structure analysis. In this study, we employed whole-genome autosomal SNPs as a marker set (54,836 SNP markers) and tested their possible effects on genetic ancestry using 320 subjects covering 24 regional groups including Northern ( = 16) and Southern ( = 3) Asians, Amerindians ( = 1), and four HapMap populations (YRI, CEU, JPT, and CHB). Additionally, we evaluated the effectiveness and robustness of 50K autosomal SNPs with various clustering methods, along with their dependencies on recombination hotspots (RH), linkage disequilibrium (LD), missing calls and regional specific markers. The RH- and LD-free multi-dimensional scaling (MDS) method showed a broad picture of human migration from Africa to North-East Asia on our genome map, supporting results from previous haploid DNA studies. Of the Asian groups, the East Asian group showed greater differentiation than the Northern and Southern Asian groups with respect to Fst statistics. By extension, the analysis of monomorphic markers implied that nine out of ten historical regions in South Korea, and Tokyo in Japan, showed signs of genetic drift caused by the later settlement of East Asia (South Korea, Japan and China), while Gyeongju in South East Korea showed signs of the earliest settlement in East Asia. In the genome map, the gene flow to the Korean Peninsula from its neighboring countries indicated that some genetic signals from Northern populations such as the Siberians and Mongolians still remain in the South East and West regions, while few signals remain from the early Southern lineages.     

白背飞虱的迁飞生物学:起飞与迁出

2001—2002年在苏州吴中区2个生长季节的田间观察和罩笼试验表明,白背飞虱Sogatella furcifera(Horváth)7月上旬以前迁入苏州,并在当地繁殖2代。从8月中下旬开始陆续有少量向外迁飞,9月份大田出现外迁高峰。田间白背飞虱起飞比率约为50%～65%,迁出峰期的每日迁出率约为80%。8月下旬白背飞虱一般已不构成危害。但20世纪90年代中期之后,白背飞虱8月份很少迁出而在迁入地大量滞留形成增殖代和主害代,危害时间大大延长,这与20世纪80年代的发生规律有了很大的不同。轨迹分析表明,8月中下旬从苏州迁出的个体中,40%可以到达江淮稻区,另有大约40%进入黄海和东海海域,若有强西南低空急流出现时则可跨海到达韩国和日本。9月份则主要是迁往我国的南方稻区,但很少可以直达岭南地区。     

大尺度下褐飞虱种群空间结构初步分析

褐飞虱是我国主要的水稻害虫,有着复杂的空间结构.地统计学可用来分析空间相关变量的结构和插值模拟空间相关变量的分布.运用地统计学中的变差函数和克立格插值法对广东省褐飞虱种群3个主要世代在早稻田间的空间结构进行分析和模拟的结果表明,大尺度的褐飞虱田间种群的空间分布为聚集型,不同世代褐飞虱种群的局部空间结构有差异,聚集的范围分别为400、200和205km;空间分布模拟地图能反映褐飞虱种群在田间的具体分布情况,广东西部地区每一世代褐飞虱的发生密度均高于东部地区.     

大尺度下褐飞属种群空间结构初步分析

褐飞虱是我国主要的水稻害虫,有着复杂的空间结构,地统计学可用来分析空间相关变量的结构和插植模拟空间相关变量的分布,运用地统计学中的变差函数和克立格插值法对广东省褐飞虱种群3个主要世代在早稻田间的空间结构进行分析和模拟的结果表明,大尺度的褐飞虱田间种群的空间分布为聚集型,不同世代群在田间的具体分布情况,广东西部地区第一世代褐飞虱的发生密度均高于东部地区。     

Invasion pathway of the honeybee pest,small hive beetle,Aethina tumida (Coleoptera: Nitidulidae) in the Republic of Korea inferred by mitochondrial DNA sequence analysis

The small hive beetle (SHB), Aethina tumida, is native to the Sub-Saharan region of Africa, but it became invasive in many countries after its first introduction to the USA in 1996. The SHB is a destructive pest of the honey industry and can cause damage in apiaries due to feeding on the honey, pollen, honey bee brood and honey fermentation. SHB was recently found infesting honeybee colonies in the South-Eastern part of Korea, Miryang city in 2016. No inference of the origin or the pathway of the invasion into Korea has been made, so far. We analyzed partial cytochrome oxidase I gene of mitochondrial DNA to unveil the possible source of the invasive populations of SHB in South Korea. A Bayesian inference tree and median joining haplotype network revealed a strong relationship between South Korean and North American populations suggesting that the SHB in South Korea came from the USA. Low genetic variation among Korean populations suggests that the invasion might have occurred in a single event with small number of founders. In addition, a new global distributional map of SHB is provided.     

“海棠”台风气流场对褐飞虱北迁路径的影响

基于GIS、GrADS软件和HYSPLIT 4.8轨迹模式,分析了0505号台风“海棠”发生期间（2005年7月19—21日）中国10个省42个虫情观测点的逐日灯诱褐飞虱虫量、850 hPa等压面的风场和20个虫情监测点的褐飞虱迁飞轨迹.结果表明：台风“海棠”登陆中国后,改变了引导褐飞虱向北迁飞的西南气流,造成风场在台风西南部的辐合和大范围的转向,阻止了褐飞虱的向北迁飞,迫使其在某些区域集中迫降;850 hPa等压面上切变线附近是褐飞虱集中降落的区域;在台风衰亡时期,台风东南部气流暖式切变区是大量降虫的区域;台风整体登陆后,西南气流的再次建立,造成褐飞虱的大量北迁.     

台风莫兰蒂对褐飞虱迁飞的影响

通过对2010年10号台风莫兰蒂(Meranti)进行流场分析和过程分析,阐明了此次台风对浙江稻区9月上中旬褐飞虱Nilaparvata Lugens(Stl)的迁飞造成的影响。结果表明:(1)台风过境前,其外围前方的强东南气流及高空下沉气流为褐飞虱提供了运载工具和降落条件,虫源基本来自浙江东南部和迁入区附近区域;(2)台风过境时,由于天气恶劣,部分站点上灯虫量很小,但金华和遂昌处于台风眼范围内,天气较好,风速较小,为之前随大风和降雨迁入的大量虫群提供上灯的机会,造成上灯高峰,虫源地主要来自浙江省南部;(3)台风过境后,受台风后部西南风和降雨影响,福建中北部和南部有褐飞虱随降雨迁入浙江稻区,但虫量较小。(4)根据浙江为东部临海的地理位置和台风的气旋式辐合流场的特点,从本研究结果看,莫兰蒂台风的影响仅为中小尺度范围。     

Trajectory modeling revealed a southwest-northeast migration corridor for fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) emerging from the North China Plain

The fall armyworm Spodoptera frugiperda, an invasive insect pest native to the Americas, has established populations throughout eastern China. The North China Plain—a key corn-producing area in East China with a unique topography—was invaded by fall armyworm in 2019 and is seriously threatened by this migratory pest. However, the spatiotemporal extent of the migratory movements of fall armyworm from the North China Plain remains poorly understood. Using an air transport-based trajectory modeling approach that incorporates flight behavior, we simulated the potential nocturnal migration trajectories of fall armyworm from the North China Plain based on historical meteorological data from June to October of 2015–2019, and examined the night-time atmospheric conditions associated with their possible flights. The emigration patterns showed monthly variation in the main landing area and common migration direction. The displacement of newly emerged moths from the North China Plain was concentrated in the Northeast China Plain (including Liaoning, Jilin and Heilongjiang provinces) before late summer, after which they were most likely to undertake return flights to the south (especially into Hubei, Anhui and Hunan provinces). This southwest-northeast aerial migration corridor follows the topography of East China and is affected by the East Asian monsoon. These topographic-atmospheric conditions have resulted in the North China Plain becoming a key stopover for fall armyworm populations engaging in multigenerational long-distance migration across East China. These findings contribute to our knowledge of fall armyworm migration and will aid in the implementation of management and control strategies against this highly migratory agricultural pest.     

Pseudococcus orchidicola (Hemiptera: Pseudococcidae), a newly found mealybug pest,confused with P. longispinus in Korea

Pseudococcus longispinus, a notorious cosmopolitan pest species of mealybugs, known to be distributed indoors in Korea since 2002, is found to be mixed with another species, Pseudococcus orchidicola. Finding P. orchidicola as a pest of tropical plants in Korea is rather unexpected because of their main distribution in the Pacific area and South Asia. However, all the available information from morphology, molecule and advice on identification from mealybug specialists indicates this is the best match for P. orchidicola. Morphological, molecular and some biological notes on P. orchidicola are provided with some adult and nymphal images, and compared with P. longispinus. A full discussion mainly on identity and distribution of P. orchidicola is given.     

Rice planting systems, global warming and outbreaks of Nilaparvata lugens (Stål)

Brown Planthopper (BPH, Nilaparvata lugens (St?l)) is one of the most serious pests of rice in both temperate and tropical regions of East and South Asia and has become especially problematic over the past few years. In order to analyze the effect of the change of rice cropping system on the population dynamics of BPH, field surveys of the occurrence and distribution of BPH were performed and other relevant data, including light trap data and ovary dissection data were collected in nearly 40 Chinese counties encompassing six provinces (or municipalities), including Hainan, Guangxi, Anhui, Shanghai, Fujian and Guangdong from April to October in 2007.The mixed planting areas of single- and double-cropping rice in China include Hubei, South and Central Anhui, North Hunan, and North Jiangxi. In these areas, double-cropping rice has now been greatly reduced and single-cropping rice has been rapidly increasing since 1997. The surveys revealed that when the immigration peak of BPH occurred in June and July, the single-cropping rice was at the tillering to booting stage and fit for BPH, but early rice had already matured and most of late rice had not yet been transplanted. BPH immigrants from southern rice areas prefer to inhabit and breed in single-cropping rice paddies. Moreover, farming activities between early rice and late rice interrupted the continuous growth of BPH populations in double-cropping rice paddies. As a result, in comparison with data collected 30 years ago, the spatiotemporal dynamics and migration patterns of BPH have dramatically changed in the lower-middle reaches of the Yangtze River. In the mixed planting areas, due to their high suitability, the BPH population in single-cropping rice grew so quickly that it caused serious local damage and there was mass emigration of macropterous progeny to the Yangtze River Delta in late August and early September.Global warming may also affect BPH populations, where results suggest steadily warmer autumns have occurred from the 1990s on, with such conditions gradually the norm. The combination of 'cooler summer' and 'warmer autumn' are conditions known to promote outbreaks of BPH in the lower-middle reaches of the Yangtze River. Immigrant BPH arrivals in late August and September now cause serious damage to late-maturing mid-season rice and late rice in the lower-middle reaches of the Yangtze River.     

Genetic status of Asiatic black bear (Ursus thibetanus) reintroduced into South Korea based on mitochondrial DNA and microsatellite loci analysis

The Asiatic black bear is one of the most endangered mammals in South Korea owing to population declines resulting from human exploitation and habitat fragmentation. To restore the black bear population in South Korea, 27 bear cubs from North Korea and Russian Far East (Primorsky Krai) were imported and released into Jirisan National Park, a reservoir of the largest wild population in South Korea, in 2004. To monitor the success of this reintroduction, the genetic diversity and population structure of the reintroduced black bears were measured using both mitochondrial and nuclear DNA markers. Mitochondrial D-loop region DNA sequences (615 bp) of 43 Japanese black bears from previous study and 14 Southeast Asian black bears in this study were employed to obtain phylogenetic inference of the reintroduced black bears. The mitochondrial phylogeny indicated Asiatic black bear populations from Russian Far East and North Korea form a single evolutionary unit distinct from populations from Japan and Southeast Asia. Mean expected heterozygosity (H(E)) across 16 microsatellite loci was 0.648 for Russian and 0.676 for North Korean populations. There was a moderate but significant level of microsatellite differentiation (F(ST) = 0.063) between black bears from the 2 source areas. In addition, genetic evidences revealed that 2 populations are represented as diverging groups, with lingering genetic admixture among individuals of 2 source populations. Relatedness analysis based on genetic markers indicated several discrepancies with the pedigree records. Implication of the phylogenetic and genetic evidences on long-term management of Asiatic black bears in South Korea is discussed.     

Population Structure of Pacific Cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in the Southern Part of the Range Based on the Microsatellite Analyses

The population structure of Pacific cod Gadus macrocephalus in the southern part of the range and adjacent regions is studied on the basis of the results of microsatellite analyses. Collected data indicate heterogeneity of this species population within the studied area. According to the obtained F_ST values, Pacific cod from the waters of the Republic of Korea (Yellow Sea side) and northwestern part of the Sea of Okhotsk significantly differ from all other studied regions (Table 4). Significant differentiation was also revealed between samples from the waters of the Tatar Strait and all other regions except for South Kurils Pacific cod (both Sea of Okhotsk and Pacific Ocean sides). These two latter sample collections were similar to each other as well. A low level of differentiation was also shown for the Peter the Great Bay and the East Sea/Sea of Japan waters of the Republic of Korea.     

安徽大别山北坡植物区系与邻近地区植物区系关系探讨

安徽大别山北坡是大别山的主体部分,也是目前大别山森林植被保存较好的地区之一。作者通过对该区植物区系与邻近地区植物区系之间共有种和区系成分的对比分析,以及通过与邻近山地森林植物区系之间相似性系数的对比分析,初步得出下列结论:(1) 该区植物区系与华东植物区系的关系最密切,其次是华中,再次依次为日本、华北、华南、西南、东北,与西北和青藏高原植物区系之间很少有联系。(2) 该区植物区系与日本植物区系之间的关系比与我国西南植物区系之间的关系要密切。(3) 该区植物区系与天目山、神农架、中条山、庐山、武夷山诸山地森林植物区系之间关系紧密程度依次为天目山、庐山、神农架、武夷山、中条山。(4) 大别山植物区系在我国植物区系分区上应属于华东区。(5) 在我国植物区系分区上,华东区与华中区的分界线在湖北省境内应位于“襄樊—宜昌”一线,华东区与华北区的分界线在安徽省境内应位于“霍丘—滁县”一线。