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1.
Proc Natl Acad Sci U S A ; 121(18): e2317646121, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38648486

RESUMEN

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.


Asunto(s)
Altitud , Migración Animal , Estaciones del Año , Animales , China , Migración Animal/fisiología , Agricultura/métodos , Ecosistema , Insectos/fisiología , Viento , Vuelo Animal/fisiología
2.
Talanta ; 256: 124304, 2023 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-36739743

RESUMEN

As a novel pattern of regulated cell death (RCD), Ferroptosis is induced by lipid peroxide-dependent iron accumulation, which is associated with reactive oxygen species (ROS). Ferroptosis regulates cell death via ROS accumulation-related lipid peroxides accumulation, affecting the structure and polarity of lipid droplets (LDs). Compared with reactive fluorescent probes, environment-sensitive fluorescent probes allow for maximum preservation of the intracellular environment while monitoring metabolic activity in situ, resulting in more accurate monitoring results. In this study, a polarity-sensitive two-photon fluorescent probe with anchoring capacity in LDs, LIP-Pola, is reported and applied to monitor the polarity of LDs during cell Ferroptosis by in situ imaging analysis of cell Ferroptosis via LDs polarity changes. Additionally, Paclitaxel is shown to increase the Ferroptosis level from data of cells and tumor tissue sections, suggesting that Paclitaxel may deactivate tumor cells by regulating Ferroptosis.


Asunto(s)
Antineoplásicos , Ferroptosis , Gotas Lipídicas/metabolismo , Especies Reactivas de Oxígeno , Colorantes Fluorescentes/química , Peróxidos Lipídicos/metabolismo , Peróxidos Lipídicos/farmacología , Antineoplásicos/farmacología , Antineoplásicos/metabolismo
3.
Mov Ecol ; 10(1): 54, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36457049

RESUMEN

BACKGROUND: In warm regions or seasons of the year, the planetary boundary layer is occupied by a huge variety and quantity of insects, but the southward migration of insects (in East Asia) in autumn is still poorly understood. METHODS: We collated daily catches of the oriental armyworm (Mythimna separata) moth from 20 searchlight traps from 2014 to 2017 in China. In order to explore the autumn migratory connectivity of M. separata in East China, we analyzed the autumn climate and simulated the autumn migration process of moths. RESULTS: The results confirmed that northward moth migration in spring and summer under the East Asian monsoon system can bring rapid population growth. However, slow southerly wind (blowing towards the north) prevailed over the major summer breeding area in North China (33°-40° N) due to a cold high-pressure system located there, and this severely disrupts the autumn 'return' migration of this pest. Less than 8% of moths from the summer breeding area successfully migrated back to their winter-breeding region, resulting in a sharp decline of the population abundance in autumn. As northerly winds (blowing towards the south) predominate at the eastern periphery of a high-pressure system, the westward movement of the high-pressure system leads to more northerlies over North China, increasing the numbers of moths migrating southward successfully. Therefore, an outbreak year of M. separata larvae was associated with a more westward position of the high-pressure system during the previous autumn. CONCLUSION: These results indicate that the southward migration in autumn is crucial for sustaining pest populations of M. separata, and the position of the cold high-pressure system in September is a key environmental driver of the population size in the next year. This study indicates that the autumn migration of insects in East China is more complex than previously recognized, and that the meteorological conditions in autumn are an important driver of migratory insects' seasonal and interannual population dynamics.

4.
J Econ Entomol ; 115(5): 1480-1489, 2022 10 12.
Artículo en Inglés | MEDLINE | ID: mdl-35665819

RESUMEN

The white-backed planthopper, WBPH, Sogatella furcifera (Horváth) is a plant pest that migrates long-distances. The migration pathway of WBPH in eastern China coincides with the north-south round trip of the East Asian monsoon. However, in Yunnan China, which is affected by two monsoon systems, the migration pathway is unclear. Light-trap data and analysis of female ovarian development showed that the peak period of immigration of WBPH into western Yunnan was earlier than in eastern Yunnan. Using meteorological reanalysis data and flight parameters of WBPH, trajectory modeling showed that there are two immigration pathways to Yunnan. One is from Myanmar to western Yunnan, and the other is from Vietnam and Laos to eastern Yunnan. The reason for the differences in source areas and immigration pathways between eastern and western Yunnan is that the west wind prevails in western Yunnan and is controlled by South Asian monsoon, while southwesterly winds prevail in eastern Yunnan due to the combined influence of South Asian monsoon and East Asian monsoon. The results indicate that WBPH invades Yunnan via two pathways under a two-monsoon system. These data will allow earlier prediction and population management of WBPH.


Asunto(s)
Emigración e Inmigración , Hemípteros , Animales , China , Vietnam , Viento
5.
Insect Sci ; 29(6): 1672-1684, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35179825

RESUMEN

Despite the importance of reproduction in insects, its relation with multi-stop flight remains poorly understood in migratory species. To clarify whether reproductive maturation commences during the multi-stop flight or after the completion of migration, we conducted physiological and behavioral assays in the rice leaf roller Cnaphalocrocis medinalis with laboratory-simulated conditions and field-captured populations. We found that the ovarian development was significantly promoted by tethered flight treatment for 1-2 nights when compared to the unflown group, while the flight muscle development was not impaired. There was no significant difference in flight duration, flight distance and flight velocity between mated and virgin female moths, indicating that mated moths remained competent for the subsequent flights as did the virgins. Using an integrated field assay, we identified that over 60% of the female moths in the migrating populations captured by high-altitude searchlights in the Immigration period of a season had completed the ovarian development and mating. Sexually mature and mated moths collected in the rice field in the Emigration period were found capable of engaging in migratory take-off, as observed using an indoor monitoring platform. Overall, our findings point out that C. medinalis managed to complete reproductive maturation to a large extent during the multi-stop migratory flight without compromising the migration performance. Such a cost-effective strategy ensures a successful migration for the moths. These findings advance our understanding of the relationship between reproduction and migration, thus shedding light on the development of novel control measures for the outbreak of migratory insect pests.


Asunto(s)
Mariposas Nocturnas , Oryza , Femenino , Animales , Mariposas Nocturnas/fisiología , Reproducción/fisiología , Estaciones del Año
6.
Insect Sci ; 29(2): 467-477, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34498794

RESUMEN

In addition to sperm, some accessory substances transferred to females during copulation act as nuptial gifts by passing on valuable nutrients in many insect species. The nutritional status of the males can thus have a great effect on the mating behavior, fecundity and even the longevity of females. However, little is known about the effect of male nutritional status on the female reproductive traits in migratory insect species, particularly when females experience nutrient shortage and have to choose between reproduction and migration. Here, Cnaphalocrocis medinalis, a migratory rice pest in Asia, was studied to explore this issue. Our results showed that in male moths fed with honey solution, their gonads had higher energy content than gonads of starved males, resulting in increased energy content of the bursa copulatrix of females after mating with fed males. Such females showed increased mating frequency, fecundity and longevity compared to females mating with starved males, indicating that male moths deliver nuptial gifts to females and improve their reproductive performance. However, when females were starved, only about 45% mated, with just a single copulation, regardless of male nutritional status. Starved females showed lower fecundity, and a longer pre-oviposition period (indicating a greater propensity to migrate), compared to fed females. However, copulation still significantly extended their longevity. These results suggest that starved females invest in migration to escape deteriorating habitats, rather than investing the nuptial gift to increased fecundity. Our results further our understanding of the reproductive adaptability of migratory insects under conditions of food stress.


Asunto(s)
Mariposas Nocturnas , Animales , Copulación , Femenino , Masculino , Nutrientes , Estado Nutricional , Reproducción , Conducta Sexual Animal
7.
Mov Ecol ; 8(1): 48, 2020 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-33292576

RESUMEN

Migratory connectivity describes the degree of linkage between different parts of an animal's migratory range due to the movement trajectories of individuals. High connectivity occurs when individuals from one particular part of the migratory range move almost exclusively to another localized part of the migratory range with little mixing with individuals from other regions. Conversely, low migratory connectivity describes the situation where individuals spread over a wide area during migration and experience a large degree of mixing with individuals from elsewhere. The migratory connectivity concept is frequently applied to vertebrate migrants (especially birds), and it is highly relevant to conservation and management of populations. However, it is rarely employed in the insect migration literature, largely because much less is known about the migration circuits of most migratory insects than is known about birds. In this review, we discuss the applicability of the migratory connectivity concept to long-range insect migrations. In contrast to birds, insect migration circuits typically comprise multigenerational movements of geographically unstructured (non-discrete) populations between broad latitudinal zones. Also, compared to the faster-flying birds, the lower degree of control over movement directions would also tend to reduce connectivity in many insect migrants. Nonetheless, after taking account of these differences, we argue that the migratory connectivity framework can still be applied to insects, and we go on to consider postulated levels of connectivity in some of the most intensively studied insect migrants. We conclude that a greater understanding of insect migratory connectivity would be of value for conserving threatened species and managing pests.

8.
Insects ; 11(9)2020 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-32933010

RESUMEN

Recently, the most serious upsurge of the desert locust (Schistocerca gregaria) in the last 25 years is spreading across eastern Africa and southwestern Asia. Parts of the desert locust 'invasion area', namely the northern border areas of Pakistan and India, are very close to China, and whether locust swarms will invade China is of wide concern. To answer this question, we identified areas of potentially suitable habitat for the desert locust within China based on historical precipitation and temperature data, and found that parts of Xinjiang and Inner Mongolia provinces could provide ephemeral habitat in summer, but these places are remote from any other desert locust breeding areas. New generation adults of the desert locust in Pakistan and India present since April led to swarms spreading into the Indo-Pakistan border region in June, and so we examined historical wind data for this period. Our results showed that winds at the altitude of locust swarm flight blew eastward during April-June, but the wind speeds were quite slow and would not facilitate desert locust eastward migration over large distances. Simulated trajectories of desert locust swarms undertaking 10-day migrations mostly ended within India. The most easterly point of these trajectories just reached eastern India, and this is very close to the eastern border of the invasion area of desert locusts described in previous studies. Overall, the risk that the desert locust will invade China is very low.

9.
Proc Biol Sci ; 287(1928): 20200406, 2020 06 10.
Artículo en Inglés | MEDLINE | ID: mdl-32486972

RESUMEN

Large migrating insects, flying at high altitude, often exhibit complex behaviour. They frequently elect to fly on winds with directions quite different from the prevailing direction, and they show a degree of common orientation, both of which facilitate transport in seasonally beneficial directions. Much less is known about the migration behaviour of smaller (10-70 mg) insects. To address this issue, we used radar to examine the high-altitude flight of hoverflies (Diptera: Syrphidae), a group of day-active, medium-sized insects commonly migrating over the UK. We found that autumn migrants, which must move south, did indeed show migration timings and orientation responses that would take them in this direction, despite the unfavourability of the prevailing winds. Evidently, these hoverfly migrants must have a compass (probably a time-compensated solar mechanism), and a means of sensing the wind direction (which may be determined with sufficient accuracy at ground level, before take-off). By contrast, hoverflies arriving in the UK in spring showed weaker orientation tendencies, and did not correct for wind drift away from their seasonally adaptive direction (northwards). However, the spring migrants necessarily come from the south (on warm southerly winds), so we surmise that complex orientation behaviour may not be so crucial for the spring movements.


Asunto(s)
Dípteros/fisiología , Vuelo Animal , Migración Animal , Animales , Insectos , Orientación Espacial , Viento
10.
Pest Manag Sci ; 76(2): 454-463, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31237729

RESUMEN

BACKGROUND: The fall armyworm (FAW), an invasive pest from the Americas, is rapidly spreading through the Old World, and has recently invaded the Indochinese Peninsula and southern China. In the Americas, FAW migrates from winter-breeding areas in the south into summer-breeding areas throughout North America where it is a major pest of corn. Asian populations are also likely to evolve migrations into the corn-producing regions of eastern China, where they will pose a serious threat to food security. RESULTS: To evaluate the invasion risk in eastern China, the rate of expansion and future migratory range was modelled by a trajectory simulation approach, combined with flight behavior and meteorological data. Our results predict that FAW will migrate from its new year-round breeding regions into the two main corn-producing regions of eastern China (Huang-Huai-Hai Summer Corn and Northeast Spring Corn Regions), via two pathways. The western pathway originates in Myanmar and Yunnan, and FAW will take four migration steps (i.e. four generations) to reach the Huang-Huai-Hai Region by July. Migration along the eastern pathway from Indochina and southern China progresses faster, with FAW reaching the Huang-Huai-Hai Region in three steps by June and reaching the Northeast Spring Region in July. CONCLUSION: Our results indicate that there is a high risk that FAW will invade the major corn-producing areas of eastern China via two migration pathways, and cause significant impacts to agricultural productivity. Information on migration pathways and timings can be used to inform integrated pest management strategies for this emerging pest. © 2019 Society of Chemical Industry.


Asunto(s)
Migración Animal , Spodoptera/fisiología , Animales , China , Mianmar , América del Norte , Zea mays
11.
Cancer Lett ; 472: 165-174, 2020 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-31857156

RESUMEN

Tumor-targeted drug delivery systems with stimuli-response drug release have been increasingly used to improve the therapeutic efficacy of antitumor drugs. Here, we report a specific molecular recognition activation drug nanoplatform based on specially designed DNA sensor-capped doxorubicin (DOX)-loaded mesoporous silica nanoparticles (MSNs), designated as specific molecular recognition-activated nanoparticle (SMRAN). DNA sensors on the targeted nanoparticles can trigger DOX release through a conformational switch induced by MUC-1. This causes a significant difference in cell viability between breast cancer MCF-7 and normal breast Hs578bst cells (24.8% and 86.0%). In vivo experiments showed that the tumor volume was reduced 1.5-times in the SMRAN treatment group. Compared with that in the DOX group, due to significantly improved tumor accumulation and retention of DOX. The strategy of the MUC-1 activated drug delivery system is expected to provide a new perspective for clinical application.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Sistemas de Liberación de Medicamentos , Mucina-1/genética , Nanopartículas/química , Mama/efectos de los fármacos , Mama/patología , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Aductos de ADN/química , Aductos de ADN/farmacología , Doxorrubicina/química , Doxorrubicina/farmacología , Portadores de Fármacos , Liberación de Fármacos , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Células MCF-7
12.
Sci Rep ; 9(1): 18388, 2019 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-31804548

RESUMEN

Sex ratio bias is common in migratory animals and can affect population structure and reproductive strategies, thereby altering population development. However, little is known about the underlying mechanisms that lead to sex ratio bias in migratory insect populations. In this study, we used Cnaphalocrocis medinalis, a typical migratory pest of rice, to explore this phenomenon. A total of 1,170 moths were collected from searchlight traps during immigration periods in 2015-2018. Females were much more abundant than males each year (total females: total males = 722:448). Sex-based differences in emergence time, take-off behaviour, flight capability and energy reserves were evaluated in a laboratory population. Females emerged 0.78 days earlier than males. In addition, the emigratory propensity and flight capability of female moths were greater than those of male moths, and female moths had more energy reserves than did male moths. These results indicate that female moths migrate earlier and can fly farther than male moths, resulting more female moths in the studied immigratory population.


Asunto(s)
Migración Animal/fisiología , Metabolismo Energético/fisiología , Vuelo Animal/fisiología , Mariposas Nocturnas/fisiología , Animales , Sesgo , Femenino , Larva/fisiología , Masculino , Oryza/parasitología , Reproducción/fisiología , Factores Sexuales , Razón de Masculinidad
13.
Insects ; 10(10)2019 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-31635147

RESUMEN

Migration is a costly strategy in terms of reproduction output. Competition for limited internal resources leads to physiological management of migration-reproduction trade-offs in energy allocation. Migratory insects must choose to determine to allocate energy into reproduction or migration when confronted insufficient energy supply. Although nutrient shortage is known to stimulate insect migration to escape deteriorating habitat, little is known about when and how migratory insects make decisions when confronted by a nutritional shortage. Here Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), a migratory rice pest in eastern Asia, was used to study the effects of starvation on reproductive traits, behavioral traits and energy allocation. The result showed that one or two days' starvation before preoviposition did not significantly reduce the fertility (total egg per female laid) and flight capability (flight duration and distance) of both sexes C. medinalis. The preoviposition period was extended significantly only if moths were starved starting on the first day after emergence. Also, take-off percentage of moths starved since their first day increased significantly, and continued to increase even if supplemental nutrients were supplied as honey solution in later days. Moths starved on the first day appeared to allocate or transfer triglycerides into the thorax to maintain the migration process: the quantity of thoracic triglycerides did not differ with age, but abdominal triglycerides decreased with age if starvation continued. These results indicate that the first day post-emergence is a critical period for C. medinalis to decide to migrate or not in response to lack of food. This furthers our understanding of the population dynamics of migratory insects under natural conditions.

14.
PLoS One ; 14(9): e0222214, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31491008

RESUMEN

Light traps are used to determine the temporal and spatial dynamics of the migratory brown planthoppers (BPHs) Nilaparvata lugens. But very little is known whether newly emerged adults respond to local light traps during the emigration period. Thus, it is important to evaluate the efficiency of light traps in attracting emigrant and immigrant populations to improve forecasting and control of this pest. The migration periods of N. lugens were determined by field surveys in Fuyang, Zhejiang province in 2012 and Yongfu, Guangxi Zhuang Autonomous Region in 2013. Mark-release-recapture experiments with both newly emerged (unflown) and flight experienced (flown) N. lugens were conducted at the two study sites. The marking method did not have any significant effect on the survival or flight capability of the N. lugens. A total of 4800 marked flown and 8400 unflown BPHs were released at a distance of 10, 20 and 30 m from 45-watt fluorescent actinic light traps. The results showed that without wind (< 3.2 m/s) or rainfall conditions, the overall recapture rate of flown BPHs was higher than that of unflown BPHs (9.60% and 0.92%, respectively; χ21 = 589.66, P < 0.0001). Curve estimation regression analysis showed that flown BPHs were attracted to the light source at a distance of 19.77 m, and unflown BPH at a distance of 5.35 m, with these distances corresponding to a 5% recapture rate. Given that the population dynamics of BPHs in the light traps were not synchronous with that in the fields, our results indicate that only a few emerging BPHs in an infested site can be captured locally by light traps. Therefore, care must be taken in estimating the abundance of the sample to absolute local abundance during sedentary and emigration period.


Asunto(s)
Migración Animal/fisiología , Hemípteros/fisiología , Fototaxis/fisiología , Animales , Vuelo Animal/fisiología
15.
Analyst ; 144(20): 5965-5970, 2019 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-31464302

RESUMEN

Hydrogen peroxide (H2O2) plays crucial roles in immunological processes and has been revealed to be closely linked to the hypoxic-ischemic process. Thus, it is important to develop a reliable method for monitoring H2O2 in hypoxic-ischemic brain injury (HIBI). To achieve this, we report on a rationally designed fluorene-based ratiometric two-photon fluorescent probe for H2O2, i.e., FH2O2. The probe and fluorophore were tested under either one- or two-photon modes, respectively. After reacting with H2O2, the relative emission intensity ratio at wavelengths of 390-465 (Fblue) and 500-550 nm (Fyellow) of FH2O2 had a 6.5-fold increase (Fyellow/Fblue) within 40 min, and the maximal two-photon active cross-section value was detected as 66 GM at a wavelength of 750 nm. The probe exhibited high selectivity, low cytotoxicity, high sensitivity with a detection limit of 0.57 µM, and adequate photostability. After confirming satisfactory sensing performance of the probe in vitro, we were able to monitor H2O2in situ in mice with HIBI via two-photon microscopy, which could provide a potential method for clinical diagnosis during the neonatal HIBI process.


Asunto(s)
Lesiones Encefálicas/metabolismo , Isquemia Encefálica/metabolismo , Colorantes Fluorescentes/química , Peróxido de Hidrógeno/metabolismo , Imagen Molecular/métodos , Fotones , Animales , Células HeLa , Humanos
16.
Insects ; 10(6)2019 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-31167426

RESUMEN

Seasonal weather systems that establish prevailing winds and seasonal rainfall on a large scale largely determine insect migration patterns, especially for micro-insects with completely windborne migration. Recent studies indicated that the summer migration of the brown planthopper (BPH, Nilaparvata lugens) in eastern China is related to the strength and position of the Western Pacific Subtropical High-Pressure (WPSH) system and its associated wind and rainfall patterns. Compared with the BPH, the white-backed planthopper (WBPH, Sogatella furcifera) has a similar diet, analogous body size, and strong long-distance migration ability. Thus, the migration pattern for the WBPH can be speculated to be similar to that of the BPH. However, the migration pattern of the WBPH and how this pattern relates to climatic conditions have scarcely been described. Based on almost three decades of data (1977-2003), it was suggested that the WBPH in southern China (south of approximately 27° N) migrates into the middle and lower reaches of the Yangtze River after the abrupt movements of the WPSH in mid-June, similar to the BPH. By contrast, the emigration of the WBPH in southern China begins in late May. Further analysis indicated that the migration of the WBPH in late May and early June was short or unsuccessful due to heavy precipitation during the preflood season in southern China from late May to middle June. The results herein demonstrate the differences in migration patterns between two rice planthoppers in the eastern Asia migration arena. We also provide new information that could assist with forecasting outbreaks and implementing control measures against these migratory pests.

17.
J Pest Sci (2004) ; 92(2): 417-428, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30956648

RESUMEN

Rice planthoppers and associated virus diseases have become the most important pests threatening food security in China and other Asian countries, incurring costs of hundreds of millions of US dollars annually in rice losses, and in expensive, environmentally harmful, and often futile control efforts. The most economically damaging species, the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), 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 interaction of these waves of migrants and synoptic weather patterns, driven by the semi-permanent western Pacific subtropical high-pressure (WPSH) system, is of critical importance in forecasting the timing and intensity of immigration events and determining the seriousness of subsequent planthopper build-up in the rice crop. We analysed a 26-year data set from a standardised light trap network in Southern China, showing that planthopper aerial transport and concentration processes are associated with the characteristics (strength and position) of the WPSH in the year concerned. Then, using N. lugens abundance in source areas and indices of WPSH intensity or related sea surface temperature anomalies, we developed a model to predict planthopper numbers immigrating into the key rice-growing area of the Lower Yangtze Valley. We also demonstrate that these WPSH-related climatic indices combined with early-season planthopper catches can be used to forecast, several months in advance, the severity of that season's N. lugens infestations (the correlation between model predictions and outcomes was 0.59), thus allowing time for effective control measures to be implemented.

18.
Insects ; 9(3)2018 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-30189679

RESUMEN

Many methods for trajectory simulation, such as Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), have been developed over the past several decades and contributed greatly to our knowledge in insect migratory movement. To improve the accuracy of trajectory simulation, we developed a new numerical trajectory model, in which the self-powered flight behaviors of insects are considered and trajectory calculation is driven by high spatio-temporal resolution weather conditions simulated by the Weather Research and Forecasting (WRF) model. However, a rigorous evaluation of the accuracy of different trajectory models on simulated long-distance migration is lacking. Hence, in this study our trajectory model was evaluated by a migration event of the corn earworm moth, Helicoverpazea, in Texas, USA on 20⁻22 March 1995. The results indicate that the simulated migration trajectories are in good agreement with occurrences of all pollen-marked male H.zea immigrants monitored in pheromone traps. Statistical comparisons in the present study suggest that our model performed better than the popularly-used HYSPLIT model in simulating migration trajectories of H.zea. This study also shows the importance of high-resolution atmospheric data and a full understanding of migration behaviors to the computational design of models that simulate migration trajectories of highly-flying insects.

19.
Int J Biometeorol ; 62(8): 1389-1406, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29713863

RESUMEN

Mass landings of migrating white-backed planthopper, Sogatella furcifera (Horváth), can lead to severe outbreaks that cause heavy losses for rice production in East Asia. South-central China is the main infestation area on the annual migration loop of S. furcifera between the northern Indo-China Peninsula and mainland China; however, rice planthopper species are not able to survive in this region over winter. In this study, a trajectory analysis of movements from population source areas and a spatiotemporal dynamic analysis of mesoscale and synoptic weather conditions from 7 to 10 May 2012 were conducted using the weather research and forecasting (WRF) model to identify source areas of immigrants and determine how weather and topographic terrain influence insect landing. A sensitivity experiment was conducted with reduced topography using the WRF model to explain the associations among rainfall, topography, and light-trap catches of S. furcifera. The trajectory modeling results suggest that the source areas of S. furcifera immigrants into south-central China from 8 to 10 May were mainly southern Guangxi, northern Vietnam, and north-central Vietnam. The appearance of enormous catches of immigrant S. furcifera coincided with a period of rainstorms. The formation of transporting southerly winds was strongly associated with the topographic terrain. Additionally, the rainfall distribution and intensity over south-central China significantly decreased when topography was reduced in the model and were directly affected by wind circulation, which was associated with mountainous terrain that caused strong convection. This study indicates that migrating populations of S. furcifera were carried by the southwesterly low-level jets and that topographically induced convergent winds, precipitation, low temperatures, and wind shear acted as key factors that led to massive landings.


Asunto(s)
Distribución Animal , Hemípteros , Animales , China , Oryza , Lluvia , Vietnam , Viento
20.
Insect Sci ; 25(5): 916-926, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28371321

RESUMEN

Sometimes, extreme weather is vital for the population survival of migratory insects by causing sudden population collapse or outbreak. Several studies have shown that rice planthopper migration was significantly influenced by typhoons in eastern Asia. Most typhoons occur in the summer, especially in August. In August, brown planthopper Nilaparvata lugens (Stål) migrates northward or southward depending on wind direction, and thus typhoons can potentially influence its migration process and population distribution. However, this has not yet been studied. This paper reported a case study on the effects of Typhoon Soudelor on the summer migration of N. lugens in eastern China in 2015. The migration pathways of N. lugens were reconstructed for the period under the influence of a typhoon by calculating the trajectories and migration events in eight counties of the Yangtze River Valley region with ancillary information. Trajectory modelling showed that most migrants took short distance migrations (less than 200 km) under the influence of the Typhoon Soudelor. Numerous N. lugens migrants were concentrated and deposited at the rear of the typhoon during the last 5 days of Typhoon Soudelor on August 9-13 due to horizontal convergence, and this led to an outbreak population. These results indicated that the N. lugens population was redistributed by the typhoon in the summer and that the population dynamics at the rear of a typhoon should be kept under close surveillance. This study provided insight into migratory organisms adapting to atmospheric features.


Asunto(s)
Distribución Animal , Migración Animal , Tormentas Ciclónicas , Hemípteros/fisiología , Animales , China , Hemípteros/crecimiento & desarrollo , Ninfa/crecimiento & desarrollo , Ninfa/fisiología , Dinámica Poblacional
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