东北地区草地螟1999年大发生的虫源分析

草地螟是我国北方重要的迁飞性害虫,对其虫源地及迁飞路线尚缺乏全面的认识。本文分析了1999年各地草地螟主要迁入峰期的天气学背景,并对风场的时空分布及草地螟迁飞轨迹进行了模拟。结果表明：1999年东北地区大发生的草地螟只有少部分来自以往认为的“主要发生基地”,其主要虫源来自蒙古共和国东部及中蒙边境地区;草地螟盛发期东北地区气旋性天气系统对草地螟的迁入和扩散有密切的关系,据此提出可将“东北低压”、“东北低涡”的发生、发展趋势与虫源地的情况结合起来作为监测草地螟迁入的预警指标。     

WSR-88D doppler radar detection of corn earworm moth migration

Corn earworm (Lepidoptera: Noctuidae) (CEW) populations infesting one crop production area may rapidly migrate and infest distant crop production areas. Although entomological radars have detected corn earworm moth migrations, the spatial extent of the radar coverage has been limited to a small horizontal view above crop production areas. The Weather Service Radar (version 88D) (WSR-88D) continuously monitors the radar-transmitted energy reflected by, and radial speed of, biota as well as by precipitation over areas that may encompass crop production areas. We analyzed data from the WSR-88D radar (S-band) at Brownsville, Texas, and related these data to aerial concentrations of CEW estimated by a scanning entomological radar (X-band) and wind velocity measurements from rawinsonde and pilot balloon ascents. The WSR-88D radar reflectivity was positively correlated (r ²?=?0.21) with the aerial concentration of corn earworm-size insects measured by a scanning X-band radar. WSR-88D radar constant altitude plan position indicator estimates of wind velocity were positively correlated with wind speed (r ²?=?0.56) and wind direction (r ²?=?0.63) measured by pilot balloons and rawinsondes. The results reveal that WSR-88D radar measurements of insect concentration and displacement speed and direction can be used to estimate the migratory flux of corn earworms and other nocturnal insects, information that could benefit areawide pest management programs. In turn, identification of the effects of spatiotemporal patterns of migratory flights of corn earworm-size insects on WSR-88D radar measurements may lead to the development of algorithms that increase the accuracy of WSR-88D radar measurements of reflectivity and wind velocity for operational meteorology.     

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。     

草地螟2007年越冬代成虫迁飞行为研究与虫源分析

草地螟 Loxostege sticticalis L.是危害我国北方农牧业的一种重要迁飞性害虫,明确草地螟的虫源地及迁飞路线对其早期预警具有重要意义。本文利用垂直监测昆虫雷达的长期观测,迁飞高峰期雌虫卵巢解剖、大区环流分析、各地虫情信息收集和利用Hysplit_4模型进行轨迹分析,研究了2007年越冬代草地螟的空中迁飞行为和东北地区严重暴发的草地螟虫源。结果表明：6月7–9日,雷达观测点诱虫灯内草地螟具有典型迁飞昆虫生理特征;草地螟主要在夜间迁飞,飞行高度集中在300～500 m,400 m是主要飞行高度,迁飞高峰期夜间迁移可持续9 h。东北地区严重发生的草地螟虫源,一部分来自内蒙古乌盟地区,一部分来自蒙古共和国中东部及中俄边境地区。据此推测我国与国外草地螟存在虫源交流。     

云南白马雪山小地老虎蛾迁飞观察

本文报道了小地考虑蛾迁飞活动与气候因子能源物质的相互关系。1985-1988年在云南白马雪山进行了三个全年的小地考虑蛾迁飞动态的系统观察,并测定比较了不同虫源的脂肪含量。结果表明,白马雪山一年有5次迁飞蛾峰。迁飞蛾种群动态与温度、湿度、降水、风速、气压和高空50000帕的西南及北风气流有密切关系。不同虫源的雌蛾脂肪含量差异显著,迁出型含量最高,本地型次之,迁飞过境型又次于前者,迁入型含量最低。     

Inter‐individual variation in colour patterns in noctuid moths characterizes long‐distance dispersers and agricultural pests

A high capacity for long‐distance dispersal is a key to success for species confronted with environmental heterogeneity, habitat modification, fragmentation and loss. However, dispersal capacity is difficult to quantify and therefore poorly known in most taxa. Here, we report on a test for an association of variation in dispersal capacity with variable colouration of noctuid moths. First, using data from 12 experienced lepidopterologists, we showed that despite variation among experts in average assessments, different species are consistently classified as having non‐variable, variable or highly variable colour patterns when assessed by different experts. We then compared the incidence of non‐resident species with high inter‐individual variation in colour patterns recorded on the isolated island Utklippan (n = 47), with that in a species pool of potential long‐distance dispersers from the nearest mainland (n = 295). Species with high inter‐individual colour pattern variation were over‐represented on the island compared with species having non‐variable colouration. This finding constitutes rare evidence from the wild of long‐distance dispersal, measured on a spatial scale relevant for moths when tracking habitats in fragmented and changing landscapes or when keeping pace with environmental challenges associated with climate change. Finally, we showed that Swedish noctuid moths classified as agricultural pests (n = 28) had more variable colour patterns compared with non‐pests (n = 368). The majority of agricultural pests were also recorded on the isolated island, an outcome that is indicative of pest species having high dispersal capacity. Data on colour pattern variation may thus offer a simple and cost‐effective proxy to estimate dispersal capacity and can also help identify potential pest species. Our findings are potentially useful when modelling and predicting population and range dynamics of species in spatiotemporally heterogeneous environments, with direct implications for conservation biology and pest management.     

Genetic Structure and Demographic History Reveal Migration of the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae) from the Southern to Northern Regions of China

The diamondback moth Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) is one of the most destructive insect pests of cruciferous plants worldwide. Biological, ecological and genetic studies have indicated that this moth is migratory in many regions around the world. Although outbreaks of this pest occur annually in China and cause heavy damage, little is known concerning its migration. To better understand its migration pattern, we investigated the population genetic structure and demographic history of the diamondback moth by analyzing 27 geographical populations across China using four mitochondrial genes and nine microsatellite loci. The results showed that high haplotype diversity and low nucleotide diversity occurred in the diamondback moth populations, a finding that is typical for migratory species. No genetic differentiation among all populations and no correlation between genetic and geographical distance were found. However, pairwise analysis of the mitochondrial genes has indicated that populations from the southern region were more differentiated than those from the northern region. Gene flow analysis revealed that the effective number of migrants per generation into populations of the northern region is very high, whereas that into populations of the southern region is quite low. Neutrality testing, mismatch distribution and Bayesian Skyline Plot analyses based on mitochondrial genes all revealed that deviation from Hardy-Weinberg equilibrium and sudden expansion of the effective population size were present in populations from the northern region but not in those from the southern region. In conclusion, all our analyses strongly demonstrated that the diamondback moth migrates within China from the southern to northern regions with rare effective migration in the reverse direction. Our research provides a successful example of using population genetic approaches to resolve the seasonal migration of insects.     

Is Mythimna turca (Lepidoptera: Noctuidae) a migrant?

The double line moth, Mythimna turca (Linnaeus, 1761) (Lepidoptera: Noctuidae), is an important widely distributed insect species. Studies on the moth in European countries have focused on population monitoring and in China on taxonomy of Mythimna and distribution surveys of M. turca. However, whether M. turca is a migratory insect is unknown. Here, migration of the moth population was monitored using a searchlight trap from 2004 to 2020 on Beihuang island, Northern China, providing direct evidence that M. turca migrates across the Bohai Strait seasonally, in late May to early September. Population dynamics, ovarian development, wind direction and possible migration trajectories were also analyzed. Most moths migrated in June and at the end of August and the beginning of September, and a few migrated in May, July and October. The average duration of this windborne migratory period of M. turca was 93 d. Migratory trajectories demonstrated that M. turca mainly moved northward in spells of southerly winds from June to August and moved southward in spells of northerly winds during September. This new key information about the ecology of M. turca population will aid the formulation of M. turca management strategies.     

Wind selection and drift compensation optimize migratory pathways in a high-flying moth

Numerous insect species undertake regular seasonal migrations in order to exploit temporary breeding habitats [1]. These migrations are often achieved by high-altitude windborne movement at night [2-6], facilitating rapid long-distance transport, but seemingly at the cost of frequent displacement in highly disadvantageous directions (the so-called "pied piper" phenomenon [7]). This has lead to uncertainty about the mechanisms migrant insects use to control their migratory directions [8, 9]. Here we show that, far from being at the mercy of the wind, nocturnal moths have unexpectedly complex behavioral mechanisms that guide their migratory flight paths in seasonally-favorable directions. Using entomological radar, we demonstrate that free-flying individuals of the migratory noctuid moth Autographa gamma actively select fast, high-altitude airstreams moving in a direction that is highly beneficial for their autumn migration. They also exhibit common orientation close to the downwind direction, thus maximizing the rectilinear distance traveled. Most unexpectedly, we find that when winds are not closely aligned with the moth's preferred heading (toward the SSW), they compensate for cross-wind drift, thus increasing the probability of reaching their overwintering range. We conclude that nocturnally migrating moths use a compass and an inherited preferred direction to optimize their migratory track.     

棉铃虫飞翔肌的超微结构

利用电子显微镜观测表明,棉铃虫Helicoverpa rmigera (Hubner)飞翔肌的肌原纤维由400～800根肌球蛋白丝组成,每根肌球蛋白由6根肌动蛋白丝环绕排列成六角形,肌节长度2.0～3.5μm,线粒体占飞翔肌的体积达42.38%～48.57%,微气管组织较为发达。初羽化棉铃虫肌原纤维和线粒体的发育基本完成,横管系统的发育相对较慢,羽化3日后趋于成熟,至5日龄占飞翔肌的体积达3.31%～3.54%。表明棉铃虫具有适宜飞行的飞翔肌结构。采自渤海海面距海岸线80km的迁飞蛾子飞翔肌基本结构和实验种群无明显的区别,但迁飞过程中的能量代谢导致线粒体内脊疏松而出现大量空洞。     

Population dynamics of noctuid moths and damage forecasting in sugar beet

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The dynamics of sponge larvae assemblages from northwestern Mediterranean nearshore bottoms

In this study, we show for the first time the dynamics of spongelarvae assemblages from nearshore meroplankton. Plankton wascollected by SCUBA diving once or twice a week during a 2-yearperiod over a rocky artificial reef in the NW Mediterranean.Data on larval abundance were cross correlated with the valuesof environmental parameters (i.e. seawater temperature, solarradiation, wind speed and atmospheric pressure). In the laboratory,we recorded external features and main behaviors of larvae.We collected larvae belonging to 20 different taxa of sponges,which are among the most common in the sublittoral hard bottomcommunities of the NW Mediterranean and other temperate areas.There was a positive correlation between maximum abundance oflarvae and highest water temperatures. Maximum solar radiationpreceded the maximum of larval abundance. Wind speed showedno clear seasonal patterns and atmospheric pressure was overallthe lowest when larvae were most abundant. Two main patternsin the larval release periods were observed. One was shown byspecies releasing larvae in summer, right before the maximumwater temperatures (orders Dictyoceratida and Dendroceratida)and another by the species whose larvae release from the endof summer till autumn, when temperatures decrease (order Poecilosclerida).The larvae of Phorbas tenacior, Raphidoflus jolicoueri, Mycalerotalis, Tedania anhelans, Pleraplysilla spinifera, Aplysillasulfurea var. rosea and Chelonaplysilla noevus are describedfor the first time. The larvae collected mainly belonged tothe parenchymella type (except for the species Oscarella sp.and probably Cliona viridis) and showed different features andbehaviors: from the elongated parenchymellae of Scopalina lophyropoda(order Halichondrida), which show simple swimming behavior andno response to light, to the parenchymellae of Poeciloscleridaand Dictyoceratida orders with variable morphologies as adaptationsto complex swimming behaviors. Our database will hopefully contributeto the present knowledge of larval types in sponges and definitivelyhighlight the importance of this group in the dynamics of meroplanktonfrom nearshore bottoms.     

Weather-induced changes in moth activity bias measurement of long-term population dynamics from light trap samples

Interpretation of light trap catches of moths is complicated by daily variation in weather that alters flight activity and numbers caught. Light trap efficiency is also modified by wind and fog, and daily weather may effect absolute abundance (numbers actually present). However, actograph experiments and other sampling methods suggest that changes in daily activity are large by comparison to changes in absolute abundance. Daily variation in weather (other than wind and fog) is therefore a form of sampling error in absolute abundance estimates. We investigated the extent of this sampling bias in 26 years of population dynamics from 133 moth species. In a subset of 20 noctuid and geometrid species, daily numbers caught were positively correlated with temperature in 14 species, and negatively correlated with rainfall in 11 species. The strength of correlations varied between species, making it difficult to standardize catches to constant conditions. We overcame this by establishing how weather variation changed with time and duration of the flight period. Species flying later in the summer and for shorter periods experienced more variable temperatures, making sampling error greater for these species. Of the 133 moth species, those with shorter flight periods had greater population variability and more showed significant temporal density dependence. However, these effects were weak, which is encouraging because it suggests that population analyses of light trap data largely reflect factors other than sampling error.     

Interpretation of gypsy moth frontal advance using meteorology in a conditional algorithm

The gypsy moth, Lymantria dispar, is a non-native species that continues to invade areas in North America. It spreads generally through stratified dispersal where local growth and diffusive spread are coupled with long-distance jumps ahead of the leading edge. Long-distance jumps due to anthropogenic movement of life stages is a well-documented spread mechanism. Another mechanism is the atmospheric transport of early instars and adult males, believed to occur over short distances. However, empirical gypsy moth population data continue to support the possibility of alternative methods of long-range dispersal. Such dispersal events seemed to have occurred in the mid- to late-1990s with spread across Lake Michigan to Wisconsin. Such dispersal would be against the prevailing wind flow for the area and would have crossed a significant physical barrier (Lake Michigan). The climatology of the region shows that vigorous cyclones can result in strong easterly winds in the area at the time when early instars are present. It is hypothesized that these storms would enable individuals to be blown across the Lake and explain the appearance of new population centers observed at several locations on the western shore of Lake Michigan nearly simultaneously. A synoptic climatology model coupled with population dynamics data from the area was parameterized to show an association between transport events and population spread from 1996 to 2007. This work highlights the importance of atmospheric transport events relative to the invasion dynamics of the gypsy moth, and serves as a model for understanding this mechanism of spread in other related biological invasions.     

Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds

Vast numbers of insects and passerines achieve long-distance migrations between summer and winter locations by undertaking high-altitude nocturnal flights. Insects such as noctuid moths fly relatively slowly in relation to the surrounding air, with airspeeds approximately one-third of that of passerines. Thus, it has been widely assumed that windborne insect migrants will have comparatively little control over their migration speed and direction compared with migrant birds. We used radar to carry out the first comparative analyses of the flight behaviour and migratory strategies of insects and birds under nearly equivalent natural conditions. Contrary to expectations, noctuid moths attained almost identical ground speeds and travel directions compared with passerines, despite their very different flight powers and sensory capacities. Moths achieved fast travel speeds in seasonally appropriate migration directions by exploiting favourably directed winds and selecting flight altitudes that coincided with the fastest air streams. By contrast, passerines were less selective of wind conditions, relying on self-powered flight in their seasonally preferred direction, often with little or no tailwind assistance. Our results demonstrate that noctuid moths and passerines show contrasting risk-prone and risk-averse migratory strategies in relation to wind. Comparative studies of the flight behaviours of distantly related taxa are critically important for understanding the evolution of animal migration strategies.     

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.     

我国草地螟轻发年份时空特征及其气候背景

揭示我国草地螟在长时间序列上的年度间变化规律,探明轻发年份特点和研究意义,阐释气候变化背景对草地螟发生的影响方式。分析了1949—2012年我国草地螟发生面积的时间序列和轻重年份差异,利用2006—2012年北方主发区每年各代次各虫态发生期出现时间、有效持续时间和发生县点数等数据分析了轻发年份的时空分布特征。在1951—2012年可追溯的时间序列上,研究了北方草地螟主发区(169个具有连续气象资料的发生站点)年平均气温、1月月平均气温、6—8月累计降雨量等气候背景变化趋势与草地螟年度发生动态的相关性。结果表明:(1)在62年的长时间序列上,我国草地螟轻发年份频次多于重发年份;(2)轻发年份的总体特征是发生期迟、发生盛期短、发生区域少;(3)大尺度气象条件变化是引起草地螟年度发生动态波动的重要因素,与1951—2012年年度发生面积进行相关分析发现,年平均气温和1月份月平均气温与草地螟发生面积呈显著正相关关系,6—8月累计降雨量与发生面积呈显著负相关关系。分析指出,轻发年份是草地螟种群长期消长动态中不可忽视的环节,对轻发年份的研究是揭示其年度发生变化规律的重要途径;在长时间序列的分析方法上,可采用年度发生(幼虫)面积作为判断轻重年份发生程度的主要量化指标;利用草地螟发生区多点大尺度气象数据,与年度发生面积进行相关性分析,可作为阐释气候背景影响草地螟长期发生趋势的方法之一。     

Bio-ecology of false codling moth,Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) within citrus orchards in Kenya and Tanzania

1. False codling moth, Thaumatotibia leucotreta is among the key constraints of the agricultural industry. Little is known about the population dynamics and genetic diversity of this pest in East Africa.
2. The spatial–temporal population dynamics and genetic diversity of false codling moth were evaluated in citrus orchards in Kenya and Tanzania between May 2017 and August 2018 covering two fruiting seasons. The diversity of false codling moth sampled in these orchards and from solanaceous hosts, as well as from specimens received from Uganda, Sudan, and South Africa were assayed using the mitochondrial cytochrome oxidase I gene.
3. A similar spatial–temporal pattern of false codling moth was found in both Kenya and Tanzania, with the most male moths in August 2017 and 2018. In Tanzania, the number of male moths caught at high and mid altitudes did not differ but were significantly higher than those caught at low altitude.
4. A relatively low false codling moth genetic diversity was recorded at the sites where sampling was done in the respective countries as well as between specimens sampled from different host plants.
5. The low false codling moth genetic diversity determined in this trial can be exploited in the management of the pest in the studied countries.

     

Optimal strategies for insects migrating in the flight boundary layer: mechanisms and consequences

Directed aerial displacement requires that a volant organism'sairspeed exceeds ambient wind speed. For biologically relevantaltitudes, wind speed increases exponentially with increasedheight above the ground. Thus, dispersal of most insects isinfluenced by atmospheric conditions. However, insects thatfly close to the Earth's surface displace within the flightboundary layer where insect airspeeds are relatively high. Overthe past 17 years, we have studied boundary-layer insects byfollowing individuals as they migrate across the Caribbean Seaand the Panama Canal. Although most migrants evade either droughtor cold, nymphalid and pierid butterflies migrate across Panamanear the onset of the rainy season. Dragonflies of the genusPantala migrate in October concurrently with frontal weathersystems. Migrating the furthest and thereby being the most difficultto study, the diurnal moth Urania fulgens migrates between Centraland South America. Migratory butterflies and dragonflies arecapable of directed movement towards a preferred compass directionin variable winds, whereas the moths drift with winds over water.Butterflies orient using both global and local cues. Consistentwith optimal migration theory, butterflies and dragonflies adjusttheir flight speeds in ways that maximize migratory distancetraveled per unit fuel, whereas the moths do not. Moreover,only butterflies adjust their flight speed in relation to endogenousfat reserves. It is likely that these insects use optic flowto gauge their speed and drift, and thus must migrate wheresufficient detail in the Earth's surface is visible to them.The abilities of butterflies and dragonflies to adjust theirairspeed over water indicate sophisticated control and guidancesystems pertaining to migration.     

Natural enemies and environmental factors affecting the population dynamics of the gypsy moth

The population densities of the gypsy moth (Lymantria dispar; Lepidoptera: Lymantriidae) may reach outbreak levels that pose considerable economic and environmental impacts to forests in Europe, Asia, Africa and North America. Compared with the situation in its native European range feeding damage by gypsy moth is often found to be more severe in North America and other parts of the world. Thus, the release from natural enemies can be interpreted as an important cause for high feeding damages. Natural enemies, especially parasitoids, can cause delayed density‐dependent mortality, which may be responsible for population cycles. In North America where only few parasitoids have been introduced and the parasitism rates are considerably lower than in Europe, generalist predators play a larger role than in Europe. Many other factors seem to influence the population dynamics of the gypsy moth such as the host plants and weather. Nevertheless, much of the variability in population densities of the gypsy moth may be attributed to interacting effects of weather conditions and attack by natural enemies. In spite of the considerable number of studies on the ecology and population dynamics of the gypsy moth and the impact of their natural enemies, more quantitative information is required to predict the population dynamics of this pest species and to control its economic and ecologic impact.