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(A) Photograph of the display of the 8-mm wavelength scanning radar at 22.04 hrs on the evening of 28 September 1988 at Jiangpu (near Nanjing) China, showing a dense layer comprised mainly of brown planthoppers (Nilaparvata lugens) overflying the radar site between about 380 and 825 m above ground level. N. lugens comprised 90% of the radar-detectable insects in an aerial netting sample taken from the bottom of this layer. (Radar beam elevation ¼ 44 ; distance to outer range-ring ¼ 0.75 nautical miles (1390 m); the heading marker points north). (From Riley et al., 1991. Reprinted with
Source publication
The Migration of Insect Vectors of Plant and Animal Viruses
I. Introduction
A. Definition and Characteristics of Migration
B. Extended Foraging
II. Techniques for the Study of Vector Migration
A. Aerial Sampling
B. Networks of Ground-Based Traps
C. Radar
D. Artificial Markers
E. Natural Markers
F. Flight Mills and Flight Chambers
G. Trajectories...
Context in source publication
Context 1
... to allow flight to start before the air temperature at ground level fell below the threshold for take-off. After taking off the planthoppers climbed actively at a rate of c. 0.2 ms À1 , and flew for several hours during the evening, often form- ing dense concentrations 400-1000 m above ground, which produced a dramatic display on the radar screen (Fig. 1A and B). These layers often had a well-defined ceiling, which corresponded to an air temper- ature of c. 16 C, close to the minimum for sustained flight in N. lugens. The mean migration height was well above the top of the surface temperature inversion, so most of the planthoppers did not fly at the height where the air was warmest. Layers ...
Citations
... These insect ecosystem functions also constitute services and disservices that affect human agriculture, economy and health-the most relevant of which are probably crop consumption, crop pest consumption [51], and vectoring the agents of crop, livestock, wildlife and human diseases [79,80]. A prime example are locusts that are infamous worldwide for their capacity to devastate massive amounts of crop [81]. ...
In the current biodiversity crisis, populations of many species have alarmingly declined, and insects are no exception to this general trend. Biodiversity monitoring has become an essential asset to detect biodiversity change but remains patchy and challenging for organisms that are small, inconspicuous or make (nocturnal) long-distance movements. Radars are powerful remote-sensing tools that can provide detailed information on intensity, timing, altitude and spatial scale of aerial movements and might therefore be particularly suited for monitoring aerial insects and their movements. Importantly, they can contribute to several essential biodiversity variables (EBVs) within a harmonized observation system. We review existing research using small-scale biological and weather surveillance radars for insect monitoring and outline how the derived measures and quantities can contribute to the EBVs ‘species population’, ‘species traits’, ‘community composition’ and ‘ecosystem function’. Furthermore, we synthesize how ongoing and future methodological, analytical and technological advancements will greatly expand the use of radar for insect biodiversity monitoring and beyond. Owing to their long-term and regional-to-large-scale deployment, radar-based approaches can be a powerful asset in the biodiversity monitoring toolbox whose potential has yet to be fully tapped.
This article is part of the theme issue ‘Towards a toolkit for global insect biodiversity monitoring’.
... Pest insects were also important components of the small-insect fauna sampled by aerial netting above the ECP (SI Appendix, Fig. S3). Sucking hemipteran crop pests (families Delphacidae, Cicadellidae, and Aphididae), which cause physical damage and act as vectors of important crop diseases [e.g., rice black-streaked dwarf virus, maize rough dwarf virus, and barley yellow dwarf virus (11,45,49,50)], comprised 39.3% of the aerial samples of small insects (SI Appendix, Fig. S3 and Table S7). The most abundant of these were rice planthoppers (SI Appendix, Table S4), the most important rice pests globally and well-known long-distance migrants (14,35,45,51,52). ...
Long-distance migrations of insects contribute to ecosystem functioning but also have important economic impacts when the migrants are pests or provide ecosystem services. We combined radar monitoring, aerial sampling, and searchlight trapping, to quantify the annual pattern of nocturnal insect migration above the densely populated agricultural lands of East China. A total of ~9.3 trillion nocturnal insect migrants (15,000 t of biomass), predominantly Lepidoptera, Hemiptera, and Diptera, including many crop pests and disease vectors, fly at heights up to 1 km above this 600 km-wide region every year. Larger migrants (>10 mg) exhibited seasonal reversal of movement directions, comprising northward expansion during spring and summer, followed by southward movements during fall. This north–south transfer was not balanced, however, with southward movement in fall 0.66× that of northward movement in spring and summer. Spring and summer migrations were strongest when the wind had a northward component, while in fall, stronger movements occurred on winds that allowed movement with a southward component; heading directions of larger insects were generally close to the track direction. These findings indicate adaptations leading to movement in seasonally favorable directions. We compare our results from China with similar studies in Europe and North America and conclude that ecological patterns and behavioral adaptations are similar across the Northern Hemisphere. The predominance of pests among these nocturnal migrants has severe implications for food security and grower prosperity throughout this heavily populated region, and knowledge of their migrations is potentially valuable for forecasting pest impacts and planning timely management actions.
... Most of the large nocturnal migrants are moths 4 , which commonly migrate at significant 20 heights above the ground (as high as 1 km), taking advantage of seasonally favourable winds 5 . Many migratory moth species provide beneficial ecosystem functions, such as pollination 6 , but many are also economically significant pests or vectors of plant-disease viruses [7][8][9] . The detection, quantification, and characterization of moth migratory movements are therefore of great value to insect ecologists and ethologists for improving 25 our understanding of the drivers and consequences of migration. ...
The seasonal migrations of insects involve a substantial displacement of biomass with significant ecological and economic consequences for regions of departure and arrival. Remote sensors have played a pivotal role in revealing the magnitude and general direction of bioflows above 150 m. Nevertheless, the take-off and descent activity of insects below this height is poorly understood. Our lidar observations elucidate the low-height dusk movements and detailed information of insects in southern Sweden from May to July, during the yearly northward migration period. Importantly, by filtering out moths from other insects based on optical information and wing beat frequency, we have introduced a promising new method to monitor the flight activities of nocturnal moths near the ground, many of which participate in migration through the area. Lidar thus holds the potential to enhance the scientific understanding of insect migratory behaviour and improve pest control strategies.
... The closest distance between Cuba and the USA is Key West, the main island of the Keys, located 90 miles (144 km) south of Florida. Even though the vectors that transmit BTV have a limited flight time, they can be easily transported over long distances by the wind [41], even as far as 700 km under certain climatologic conditions when wind speed is sufficient [42] and orographic barriers are absent [43,44]. ...
In Cuba, despite a high sero-prevalence of bluetongue virus (BTV), circulating serotypes remain unknown. The aim of this study was to identify circulating BTV serotypes in farms throughout the western region of Cuba. Blood samples were collected from 200 young cattle and sheep between May and July 2022 for virological analyses (PCR, viral isolation and virus neutralization) and genome sequencing. The results confirmed viral circulation, with viro-prevalence of 25% for BTV. The virus was isolated from 18 blood samples and twelve BTV serotypes were identified by sequencing RT-PCR products targeting the segment 2 of the BTV genome (BTV-1, 2, 3, 6, 10, 12, 13, 17, 18, 19, 22 and 24). Finally, the full genome sequences of 17 Cuban BTV isolates were recovered using a Sequence Independent Single Primer Amplification (SISPA) approach combined to MinION Oxford Nanopore sequencing technology. All together, these results highlight the co-circulation of a wide diversity of BTV serotypes in a quite restricted area and emphasize the need for entomological and livestock surveillance, particularly in light of recent changes in the global distribution and nature of BTV infections.
... These species feed preferentially on people and/or domestic animals and are well adapted to the domestic environment. Notably, at least 7 of these 13 species have been intercepted at altitude (40-290 m above ground) [37][38][39], indicating that windborne long-range migration is common among these species, as for other insects [59][60][61][62]. The high proportion of widespread Anopheles species suggests increased dispersal capacity and faster adaptation to domestic environments, perhaps reflecting their preference to feed on medium and large mammals. ...
Mosquito-borne diseases (MBDs) threaten public health and food security globally. We provide the first biogeographic description of the African mosquito fauna (677 species) and the 151 mosquito-borne pathogens (MBPs) they transmit. While mosquito species richness agrees with expectations based on Africa's land surface, African arboviruses and mammalian plasmodia are more speciose than expected. Species assemblages of mosquitoes and MBPs similarly separate sub-Saharan Africa from North Africa, and those in West and Central Africa from eastern and southern Africa. Similarities between mosquitoes and MBPs in diversity and range size suggest that mosquitoes are key in delimiting the range of MBPs. With approximately 25% endemicity, approximately 50% occupying one to three countries and less than 5% occupying greater than 25 countries, the ranges of mosquitoes and MBPs are surprisingly small, suggesting that most MBPs are transmitted by a single mosquito species. Exceptionally widespread mosquito species feed on people and livestock, and most are high-altitude-windborne migrants. Likewise, widespread MBPs are transmitted among people or livestock by widespread mosquitoes, suggesting that adapting to people or livestock and to widespread mosquito species promote range expansion in MBPs. Range size may predict range expansion and emergence risk. We highlight key knowledge gaps that impede prediction and mitigation of future emergence of local and global MBDs.
... Long-distance insect migration occurs on an enormous scale (Bauer & Hoye, 2014;Chapman et al., 2015;Hu et al., 2016). This has implications for predator-prey interactions and ecosystem function (Krauel et al., 2017;Satterfield et al., 2020), transport of biomass and essential nutrients (Hu et al., 2016), pollination in natural and agricultural landscapes (Wotton et al., 2019), the transmission of human pathogens (Huestis et al., 2019;Reynolds et al., 2006;Yaro et al., 2022), and, perhaps most significantly, positive and negative impacts on agricultural productivity (Chapman et al., 2004;Hu et al., 2019;Li et al., 2020;Wotton et al., 2019). Most insect migrants engage in windborne movements high above the ground, where their self-propelled flight speeds are considerably slower than typical windspeeds, and thus they are transported more-or-less downwind (Chapman et al., 2010(Chapman et al., , 2015Reynolds et al., 2017). ...
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.
... However, such a transmission mode still implies vector specificity, as noted here by the lack of transmission of AYMV based on the results using 20 individuals of R. longirostre. In comparison to other insect groups, little is known regarding the spread of beetle vectors of plant viruses [64]. It can be hypothesized that A. radiolus had been involved in the dissemination of AYMV in the two collection sites. ...
Leaves of hollyhock (Alcea rosea) exhibiting vein chlorosis and yellow mosaic symptoms were collected at public sites in Lausanne and Nyon, two cities of western Switzerland. Diagnostic methods untangled in samples from both sites the mixed infections of a novel isometric virus, tentatively named “Alcea yellow mosaic virus” (AYMV) with the carlavirus Gaillardia latent virus. A new potyvirus was also identified in samples from Nyon. A combination of Illumina, Nanopore and Sanger sequencing was necessary to assemble the full-length genome of AYMV, revealing an exceptionally high cytidine content and other features typically associated with members of the genus Tymovirus. The host range of AYMV was found to be restricted to mallows, including ornamentals as well as economically important plants. Phylogenetic analyses further showed that AYMV belongs to a Tymovirus subclade that also gathers the other mallow-infecting members. The virus was readily transmitted by sap inoculation, and the weevil species Aspidapion radiolus was evidenced as a vector. Transmission assays using another weevil or other insect species did not succeed, and seed transmission was not observed.
... Insects are the most speciose taxonomic class on earth (Gaston, 1991;Stork, 2018), and provide key ecosystem functions and services, as pollinators, herbivores, predators, and decomposers (Didham et al., 1996;López-Hoffman et al., 2017;Satterfield et al., 2020;Semmens et al., 2011;Yang & Gratton, 2014). They also occur in human-modified ecosystems, often as vectors of human, livestock, or plant diseases, or as herbivores that directly damage crops (Dingle, 2009;McGeoch, 1998;Reynolds et al., 2006;Walther et al., 2002). Every year, many trillions of insects migrate from one part of the world to another, often crossing international borders (Chapman et al., 2011). ...
Several hundred butterfly species show some form of migratory behaviour. Here we identify how the methodologies available for studying butterfly migration have changed over time, and document geographic and taxonomic foci in the study of butterfly migration. We review publications on butterfly migration published in six languages (English, Simplified Chinese, Traditional Chinese, Japanese, Korean, and Spanish), summarise how migration in butterflies has been studied, explore geographic and taxonomic patterns in the knowledge base, and outline key future research directions. Using English search keywords, we found only 58 studies from Asia; however, after searching in local languages, we found an additional 98 relevant studies. Overall, butterfly migration studies are mostly from North America and Europe. Most studies focus on three species: monarch (Danaus plexippus), painted lady (Vanessa cardui) and red admiral (Vanessa atalanta). About 62% of publications are focused on the monarch, with nearly 50% of migratory butterfly species mentioned in only a single paper. Several research methods have been applied to ascribe migratory status and to study the physiology, neurobiology, and ecology of migration; however, virtually all this research is on a handful of species. There remain hundreds of species for which we do not understand the comprehensive seasonal pattern of movement, flight destinations, wintering, or breeding grounds. A better understanding of movement ecology and migratory connectivity is needed to effectively conserve migratory butterflies. It is essential that research becomes more geographically and linguistically representative since migrants frequently cross political borders and international cooperation is necessary for their conservation.
... Insects constitute about 82% of terrestrial species richness and biomass (Gaston et Stork et al., 2018), and perform key ecosystem functions and services as pollinators, herbivores, predators, and decomposers (Didham et al., 1996;Yang and Gratton, 2014;Satterfield et al., 2020). They also play important roles in human dominated ecosystems, often as vectors of human, livestock, or plant diseases, or as herbivores that directly damage crops (McGeoch, 1998;Walther et al., 2002;Dingle, 2006Dingle, , 2009Reynolds et al., 2006). About 80% of plant species depend on insects for pollination, while 60% of birds use insects as a key food source (Wagner, 2020). ...
... Migration occurs in all major insect taxonomic groups, although its prevalence varies markedly among species, even within closely related clades (Drake & Farrow, 1988;Dingle, 2001;Dingle et al., 2005). Migratory species occur in all functional groups of insects: pollinators, herbivores, predators in the broad sense, decomposers, and of course, pestsinsects that are vectors of human, livestock and plant diseases, as well as those that directly damage crops (Walther et al., 2002;Dingle, 2006Dingle, , 2009Reynolds, Chapman & Harrington, 2006). ...
Understanding which species migrate and why is critical to elucidating their ecology and planning for their conservation yet studying migration in insects is complicated by their small size and the difficulty of tracking individuals over long distances. In my PhD, I studied the movement patterns of butterflies and assessed global progress in insect conservation.
First, I conducted a comprehensive literature review, and discovered that at least 568 butterfly species show evidence of migratory movements. This suggests migration is much more widespread among butterflies than previously realised; indeed, the rate of ‘discovery’ of migratory movements in butterflies suggests that thousands of species are migratory.
The geographic distribution of butterfly migration is poorly understood. I built ecological niche models to describe and further investigate migration in migratory butterflies. I discovered strong seasonal variation in habitat suitability for most species, and the greatest rate of apparent migration occurs in the tropics. Several species showed extreme seasonal fluctuations in their distribution, and such species may be at elevated extinction risk.
Our climate is changing, including directional changes in temperature, rainfall, and timings of seasonal transitions. We might expect to see changes in migratory behaviour as a consequence. I studied the range expansion of the tawny coster butterfly. I discovered that its climatic niche differs only slightly during its colonisation of Australasia, consistent with changing conditions driving its changed distribution. The species has expanded its range in Australia at an impressive average rate of ~ 135 km/year.
Protected areas have been established around the world to preserve samples of biodiversity from pressing threats, yet the adequacy of protected area systems in many tropical nations is poorly understood. I assessed the extent to which butterflies are covered by protected areas in a mega-populated country, Bangladesh. Using three different methods to map species distributions, I found that the current protected area distribution in Bangladesh is inadequate for conserving butterflies, with <1.5% of butterflies’ geographic range being covered by protected areas.
Most assessments of protected area performance focus on vertebrates, and the effectiveness and performance of protected areas for conserving insects is mostly unknown. There is no large-scale assessment of whether the world’s protected areas are adequate for conserving insects, nor whether these areas remain effective under climate change scenarios. I conducted the first ever assessment of the extent to which insects are represented in the global network of protected areas. Measuring geographic range in two different ways, I discovered that more than 75% of insects are inadequately conserved in protected areas.
Overall, the work has helped improve our understanding of the prevalence and characteristics of migration in insects and highlight some of the major shortfalls in global conservation efforts for insects in a changing world.
... LCP method also confirmed that the habitat of Culicoides is connected, and Culicoides is likely to move between suitable habitats to spread the disease of AHS. But The importation and cross-border movement of livestock carrying the virus could also contribute to the spread of the disease, and the effect of wind on the movement of Culicoides cannot be ignored, but cannot be control 48,49 . ...
African horse sickness (AHS) is a devastating equine infectious disease. On 17 March 2020, it first appeared in Thailand and threatened all the South-East Asia equine industry security. Therefore, it is imperative to carry out risk warnings of the AHS in China. The maximum entropy algorithm was used to model AHS and Culicoides separately by using climate and non-climate variables. The least cost path (LCP) method was used to analyze the habitat connectivity of Culicoides with the reclassified land cover and altitude as cost factors. The models showed the mean area under the curve as 0.918 and 0.964 for AHS and Culicoides . The prediction result map shows that there is a high risk area in the southern part of China while the habitats of the Culicoides are connected to each other. Therefore, the risk of introducing AHS into China is high and control of the border area should be strengthened immediately.
