转基因抗虫水稻对水稻害虫群落的影响

本文应用吸虫器法与剥查法,研究了转Cry1Ac +SCK基因水稻及其杂交后代对水稻害虫群落的影响。结果显示：转Cry1Ac+SCK基因水稻MSA与MSB对稻纵卷叶螟具有极强的抗性,转Cry1Ac+SCK基因稻的杂交后代21S/MSB与Ⅱ32A/MSB都获得了对稻纵卷叶螟的高抗性。虽然MSA、MSB、21S/MSB与Ⅱ32A/MSB对水稻害虫的物种丰富度、个体数量、多样性与均匀度时间动态都有一定程度的影响,但生长全期的调查结果显示,与对应的对照比较,它们对水稻害虫群落的这些参数均无显著影响,且转基因水稻田与各自对照田在害虫与主要害虫物种组成上具有较高的相似性。靶标害虫种群数量的降低,并未对水稻害虫群落的组成与结构产生明显的影响,也没有引起优势种成分的变化。     

Effects of agricultural diversification on the abundance, distribution, and pest control potential of spiders: a review

A review of the literature showed that spider abundance was increased by diversification in 63% of studies. A comparison of diversification modes showed that spider abundance in the crop was increased in 33% of studies by `aggregated diversification' (e.g. intercropping and non-crop strips) and in 80% of studies by `interspersed diversification' (e.g., undersowing, partial weediness, mulching and reduced tillage). It is suggested that spiders tend to remain in diversified patches and that extending the diversification throughout the whole crop (as in interspersed diversification) offers the best prospects for improving pest control. There is little evidence that spiders walk in significant numbers into fields from uncultivated field edges, but diversification at the landscape level serves to foster large multi-species regional populations of spiders which are valuable as a source of aerial immigrants into newly planted crops. There are very few manipulative field studies where the impact of spiders on pests has been measured in diversified crops compared with undiversified controls. It is encouraging, however, that in those few studies an increased spider density resulted in improved pest control. Future work needs are identified.     

Spider predation on a mirid pest in Japanese rice fields

Spiders are common generalist predators, and understanding their potential in biological control is important for the development of integrated pest management programs. In this study, predation by three groups of spiders on the mirid bug Stenotus rubrovittatus (Hemiptera: Miridae) in rice paddies was investigated using DNA-based gut-content analysis. A laboratory feeding study revealed that the detection half-lives of bug DNA in the spider gut at 25 °C was 3.4 days for Lycosidae and 1.5 days for Tetragnathidae. Individual spider predation on the mirid bug was investigated by detecting DNA of prey in field-collected spiders. In total, 1199 spiders were assayed from three spider groups: Pirata subpiraticus (Lycosidae), Tetragnatha spp. (Tetra-gnathidae), and Pachygnatha clercki (Tetra-gnathidae), which each differ in their preferred microhabitat as well as their predatory habits. Detection rates of prey DNA in spiders increased significantly with the density of prey across all spider groups. P. subpiraticus and Tetragnatha spp. predation showed a better fit to a saturated response curve to increasing prey density, while P. clercki showed a simple linear relationship with prey density. Densities of alternative prey species did not affect the detection rates of mirids. These results suggest that predation on pests by generalist predators in an agroecosystem is affected not only by prey abundance but also by predator preference for specific prey. Predator preference is therefore an important factor to consider when estimating the role of natural enemies as biological control agents.     

纳米杀虫剂及其在农业害虫防治中的应用

纳米技术在农业领域的应用受到极大关注,期望该技术可提高农药和肥料的利用率,提升应用效果。近年来,纳米技术在农业害虫防控方面取得了许多进展,为绿色农业、现代化农业、智能农业的发展奠定了基础。本文综述了纳米杀虫剂的应用优势和增效途径的研究现状。纳米杀虫剂的优势源于：纳米载体可能损伤害虫体壁造成失水或扰乱害虫的正常生理功能;功能化的纳米载体可实现靶向递药而提高药物利用率;纳米载体上功能基团的引入及其尺度效应,提高了杀虫剂在植物表面的粘附性及被植物吸收的性能;可运载核酸农药进入植物,进而调控植物或害虫的目标基因的表达。纳米杀虫剂虽表现出诸多优势,但仍有问题亟待研究：(1)植物吸收纳米杀虫剂依赖于颗粒尺度和载体种类,应根据应用场景选择适合的尺度和载体,在提高农药利用率的同时降低农药残留;(2)应结合纳米杀虫剂在自然环境中的降解、转移和富集行为及因载体差异而产生的影响,综合评价纳米杀虫剂的环境风险;(3)目前,大多数纳米杀虫剂的制备工艺过于复杂和精细而不适合工业化生产;(4)应制定纳米杀虫剂制剂的标准及环境风险评价准则,为农药登记提供依据。此外,纳米传感器在农业害虫监测中的应用也值得关注。     

Sustainable pest regulation in agricultural landscapes: a review on landscape composition, biodiversity and natural pest control

Agricultural intensification has resulted in a simplification of agricultural landscapes by the expansion of agricultural land, enlargement of field size and removal of non-crop habitat. These changes are considered to be an important cause of the rapid decline in farmland biodiversity, with the remaining biodiversity concentrated in field edges and non-crop habitats. The simplification of landscape composition and the decline of biodiversity may affect the functioning of natural pest control because non-crop habitats provide requisites for a broad spectrum of natural enemies, and the exchange of natural enemies between crop and non-crop habitats is likely to be diminished in landscapes dominated by arable cropland. In this review, we test the hypothesis that natural pest control is enhanced in complex patchy landscapes with a high proportion of non-crop habitats as compared to simple large-scale landscapes with little associated non-crop habitat. In 74% and 45% of the studies reviewed, respectively, natural enemy populations were higher and pest pressure lower in complex landscapes versus simple landscapes. Landscape-driven pest suppression may result in lower crop injury, although this has rarely been documented. Enhanced natural enemy activity was associated with herbaceous habitats in 80% of the cases (e.g. fallows, field margins), and somewhat less often with wooded habitats (71%) and landscape patchiness (70%). The similar contributions of these landscape factors suggest that all are equally important in enhancing natural enemy populations. We conclude that diversified landscapes hold most potential for the conservation of biodiversity and sustaining the pest control function.     

Influence of the surrounding landscape on crop colonization by a polyphagous insect pest

Landscape composition plays an important, but poorly understood, role in the population dynamics of agricultural pest species with broad host ranges including both crops and weeds. One such pest, the generalist plant bug Lygus hesperus Knight (Hemiptera: Miridae), is a key cotton pest that feeds on various hosts differing in quality in California's San Joaquin Valley (USA). We investigated the effects of 15 common crops and uncultivated agricultural land on L. hesperus populations, by correlating the densities of L. hesperus in focal cotton fields with the areas of the 16 crops in surrounding rings. Insect counts were provided by private pest‐control advisors, and spatial data were obtained from Kern County records. We first calculated Spearman's partial correlation coefficients on an annual basis for each crop separately, and then performed a meta‐analysis of these correlations across years to describe the overall effect of a particular crop on L. hesperus after the effects of the 15 other crops are removed. Consistent with studies conducted in other areas, L. hesperus density was positively correlated with safflower, and negatively with cotton. Lygus hesperus density was also correlated with several other crops that are often not considered in pest management, including grape, oat, and onion (positive correlations), and almond, pistachio, and potato (negative correlations). Lygus hesperus density was also found to be negatively correlated with alfalfa and positively correlated with uncultivated habitats, a relationship that receives mixed support in the literature. Several other crops tested were not significantly correlated with L. hesperus densities in focal cotton fields, suggesting a neutral role for them in L. hesperus dynamics. The improved understanding of the effects of a greater variety of crops on L. hesperus population dynamics will be useful in the design of agricultural landscapes for enhanced management of this important polyphagous pest.     

Metacommunities of spiders in grassland habitat fragments of an agricultural landscape

Arthropod communities in fragmented agricultural landscapes depend on local processes and the interactions between communities in the habitat islands. We aimed to study metacommunity structure of spiders, a group that is known for high dispersal power, local niche partitioning and for engaging in species interactions. While living in fragmented habitats could lead to nestedness, other ecological traits of spiders might equally lead to patterns dominated either by species interactions or habitat filtering. We asked, which community pattern will prevail in a typical agricultural landscape with isolated patches of semi-natural habitats. Such a situation was studied by sampling spiders in 28 grassland locations in a Hungarian agricultural landscape. We used the elements of metacommunity structure (EMS) framework to distinguish between alternative patterns that reveal community organization. The EMS analysis indicated coherent species ranges, high turnover and boundary clumping, suggesting Clementsian community organization. The greatest variation in species composition was explained by local habitat characteristics, indicating habitat filtering. The influence of dispersal could be detected by the significant effect of landscape composition, which was strongest at 500 m. We conclude that dispersal allows spiders to respond coherently to the environment, creating similar communities in similar habitats. Consistent habitat differences, such as species rich versus species poor vegetation, lead to recognisably different, recurrent communities. These characteristics make spiders a predictable and diverse source of natural enemies in agricultural landscapes. Sensitivity to habitat composition at medium distances warns us that landscape homogenization may alter these metacommunity processes.     

The effect of landscape complexity and microclimate on the thermal tolerance of a pest insect

Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the function of agroecosystems. This study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global climate change. Meteorological data were measured at the landscape level, and cereal aphids (Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi) sampled, from contrasting landscapes (simple and complex) in winter 2013/2014 and spring 2014 in cereal fields of Brittany, France. Aphids were returned to the laboratory and the effect of landscape of origin on aphid cold tolerance (as determined by CT_min) was investigated. Results revealed that local landscape complexity significantly affected microclimate, with simple homogenous landscapes being on average warmer, but with greater temperature variation. Landscape complexity was shown to impact aphid cold tolerance, with aphids from complex landscapes being more cold tolerant than those from simple landscapes in both winter and spring, but with differences among species. This study highlights that future changes to land use could have implications for the thermal tolerance and adaptability of insects. Furthermore, not all insect species respond in a similar way to microhabitat and microclimate, which could disrupt important predator–prey relationships and the ecosystem service they provide.     

Effects of landscape connectivity on the spatial distribution of insect diversity in agricultural mosaic landscapes

European agricultural landscapes are mosaics of intensively cultivated areas and semi-natural elements. Although comprising only a small fraction of the total area, semi-natural elements provide habitat for most of the landscape biodiversity. Agricultural intensification has increasingly fragmented semi-natural elements and species numbers are in decline. Insights into the effects of landscape structure on species’ distributions within and among semi-natural habitats are needed to conserve biodiversity in agricultural landscapes more effectively. We investigated the landscape- and habitat-specific diversity partitions of wild bees, true bugs, and carabid beetles in two differently structured agricultural landscapes in Switzerland. In each landscape, we partitioned the total species diversity (γ) into its additive components within (_P) and among patches (β_P) and among habitats (β_H). In the landscape characterized by a patchy, isolated distribution of habitat elements, among-patch diversity (β_P) explained 44% of the total species richness (γ) and was significantly higher than expected under a random distribution of samples among habitat patches; in the landscape with higher habitat connectivity, among-patch diversity (β_P) comprised 32% of the total species richness (γ) and did not differ from the random expectation. Habitat-specific within-patch contributions to species richness were similarly low across habitat types (_P=23–24%) in the patchy landscape, whereas in the more connected landscape within-patch partitions tended to be higher and differed among habitat types (_P=22–38%). Functionally different groups of bees, true bugs, and carabids also responded differently to landscape structure in a manner that was consistent with known differences in resource specialization and dispersal ability. Differences in diversity partitions among landscapes and taxa indicate the need for flexible conservation strategies. Conservation of habitat-specific diversity may require more habitat patches in landscapes that have lower habitat connectivity and low within-patch diversity (_P) than in landscapes with higher within-patch diversity (_P).     

农业景观中环境因素对两栖类生物分布的影响

以黄河下游地区封丘县为研究区,在地理信息系统和R软件的支持下,在栖息地水平和景观水平上,分析了两栖类生物分布与栖息地变量(池塘水体溶解氧DO、电导率COND、浊度TURB、水体氨氮NH₃-N、池塘内植被盖度VEG_interior、池塘内挺水植物盖度EMER、池塘边缘植被盖度VEG_edge、两栖类幼虫捕食者PRE和池塘面积AREA)和采样点池塘250、500、1000、2000 m半径缓冲区内景观变量(池塘面积AP、与最近道路的距离DR、耕地面积AF、林地面积AW、Shannon多样性指数SHDI和蔓延度指数CONTAG)的关系.结果表明: 中华大蟾蜍的分布主要与栖息地变量中的PRE和较大缓冲区半径内的景观变量(AW2000、DR2000、SHDI1000、CONTAG1000)相关;黑斑侧褶蛙的分布与栖息地变量中的EMER和较小缓冲区半径内的景观变量(SHDI500)关系密切;金线侧褶蛙的分布主要与栖息地变量中的VEG_interior和PRE相关;泽陆蛙的分布主要与较大缓冲区半径内的景观变量(AF2000、SHDI2000)相关;两栖类生物总体上主要与栖息地变量中的EMER和较小缓冲区半径内的景观变量(SHDI500)相关.在农业景观中,保护两栖类生物应该保护永久性和半永久性池塘、提高池塘内部植被盖度、增强栖息地池塘之间的功能连通性.     

Effects of vegetation structure and landscape complexity on insect parasitism across an agricultural frontier in Argentina

Insect parasitism patterns are influenced by vegetation structure and landscape complexity. Our objective was to examine the effects of vegetation structure and landscape complexity on parasitism based on direct measurements of structure and diversity indices as well as on metrics based on remote sensing using Quickbird images. We collected 2266 lepidopteran larvae and pupae, including different families and habits, to estimate parasitism, and recorded vegetation characteristics in five 100-m² transects and 18 1 ha-plots in the dry Chaco, Northwest Argentina. We calculated landscape metrics and semivariograms in the plots from the image. The plots represented four “complexity groups”: agricultural, riparian/hedgerow, bare ground, and forest plots. Mean parasitism in the study sites was 10.7% (min: 0%, max: 23%). Parasitism was highest in agricultural plots, lowest in forest plots, and intermediate in riparian/hedgerow and bare ground plots. The landscape model explained parasitism more than the vegetation model. The landscape final model included Normalized Difference Vegetation Index (NDVI) Range, a measure of landscape heterogeneity, and Mean Shape Index, a measure of patch shape irregularity, and their interaction. The vegetation model included basal area and the Coefficient of Variation of tree density among transects, a measure of tree spatial distribution within a plot. Our results agree with previous studies that found higher parasitism in agricultural vs. non-agricultural environments in the subtropics, while riparian/hedgerow plots were important for conserving parasitism, as reported for temperate environments. We showed that under-explored tools such as the semivariogram and satellite band combinations were useful for the assessment of parasitism and that studying vegetation and landscape complexity simultaneously can help us examine mechanisms in detail. The identified variables related to high parasitism should be used for image classifications with a functional approach.     

中国农业生态系统昆虫授粉功能量与服务价值评估

所有开花植物中大约有80%的物种需要动物作为授粉媒介。系统介绍了中国重要栽培作物花的结构和类型,授粉过程、媒介和方式,作物对昆虫授粉的依赖程度,昆虫授粉功能与服务的概念,以及昆虫授粉功能量与服务价值量的评估方法;同时评估了我国各省农业生态系统中昆虫对重要作物的授粉功能量与服务价值量。结果表明:粮食作物、水果作物、蔬菜作物和经济作物不同程度的依赖昆虫授粉。根据2015年主要农作物产量、作物产品价格、昆虫授粉依赖程度等数据,计算得出昆虫对我国22类主要农作物的授粉功能量为1.8亿吨农产品产量和授粉服务价值为8860.5亿元(占当年GDP的1.3%),具有巨大的经济价值。2015年昆虫对主要栽培作物的授粉功能量和服务价值排在前五名的都是山东、河南、河北、陕西和新疆,年授粉服务价值均大于500亿元,反映出这5个省的主要农作物对昆虫授粉依赖程度较高。昆虫对作物的授粉功能量评价有助于了解昆虫对作物生物量或产量的生物学和生态学效应以及作物对昆虫授粉的需求。昆虫对作物的授粉服务价值评估有助于掌握昆虫授粉为人类所带来的经济效应或经济价值,并帮助决策维持或增强授粉昆虫多样性和种群数量的人力、物力和财力投入。     

Climate-mediated population dynamics enhance distribution range expansion in a rice pest insect

Environmental fluctuations can influence invertebrate population dynamics over large spatial scales, and effects of climate change are of particular importance in understanding phenology. In this study, we tested whether changing climate patterns could increase voltinism and emergence synchrony in Stenotus rubrovittatus and drive the mirid bug’s expansion into currently uninhabited areas of Japan. This expansion could have potentially serious economic consequences for the rice industry. We modelled development of S. rubrovittatus in the field applying the effective accumulated temperature model to calculate the theoretical number of generations and the egg hatching dates from 2003 to 2012 based on a high-resolution, daily weather database. We then performed a regional analysis to assess the relationship between population dynamics and range expansion across the study region and also included a local analysis to evaluate how population parameters affect the presence of S. rubrovittatus at local sites in each year. Results showed that distribution expanded with a relative increase in voltinism and with synchrony of egg hatching date. Moreover, we showed that increased voltinism in the previous year positively influenced local population occurrence. This positive effect suggests that the species’ distribution range expands through increased reproduction at both the regional and local scale. Climate-mediated population dynamics play a significant role in range expansion of the mirid bug.     

Effects of meteorological factors and global warming on rice insect pests in Korea

We examined the occurrence patterns of insect pests in paddy fields using a self-organizing map (SOM) and the influence of meteorological factors on these patterns. Data for nine insect pests and three meteorological factors were collected on the Korean nationwide scale from 1992 to 2008. The SOM analysis was based on annual mean densities of each pest species in eight regions. We classified the samples into five clusters (I–V) to display the spatial and temporal changes in the insect pests' occurrences. Clusters I and II included samples collected before 2000; clusters III and IV included samples collected after 2000. The density of Scotinophara lurida was in the lowest range in clusters I and II, and Lissorhoptrus oryzophilus exhibited higher densities in clusters III and IV. Seasonal temperature, humidity, and precipitation were significantly different among clusters, indicating that these factors play a key role in population dynamics and the occurrence of insect pests. The occurrence area of the insect pests was expected to increase with elevated air temperature influenced by global warming based on the IPCC (Intergovernmental Panel on Climate Change) A1B scenario. This study suggests that gathering data on temporal and spatial variations in pest populations and changes in occurrence rate under the effects of global warming can provide insight into the factors governing the population-environment relationships, as well as the information needed for future pest management.     

小尺度下柠条林破碎化生境对地表甲虫多样性的影响

一般认为,景观斑块面积和破碎化对物种丰富度和分布格局有重要的影响。在宁夏中部荒漠地区,天然柠条林和人工柠条林地交错排列,形成点、片、带状等大小不等的斑块性分布,表现为典型的破碎化斑块格局生境特征。本文采用巴氏罐诱法调查了在小尺度下荒漠景观人工柠条林破碎化生境不同斑块内地表甲虫的物种多样性。结果共获得10科20属29种地表甲虫,其中拟步甲科昆虫占绝对优势,阿小鳖甲Microdera kraatzi alashanica Skopin、克小鳖甲Microdera kraatzi kraatzi(Reitter)为优势种。Rarefaction曲线显示较大面积的斑块有较多的物种多样性,但群落多样性指数各斑间块差异不显著。利用斑块面积对物种数-个体数进行回归分析表明,地表甲虫的物种多样性受斑块面积的影响,生境破碎化会导致地表甲虫多样性下降。     

Integrated rice insect pest control in the Guangdong Province of China

There are about 13 species of rice insect pests which are common and of major significance in Guangdong Province, China. Rice pest management in China is based on cultural practices, biological control, insecticides, light traps, varietal resistance and other control methods. Natural control by preservation of natural enemies of pests plays a very positive role in the integrated control of rice pests. The major measures and techniques of these control methods are mentioned in this paper. A list of main insect pests of rice, their natural enemies and some examples of the results of rice pest integrated control in Guangdong Province, China, are also given.     

Effects of a sex-ratio distorting endosymbiont on mtDNA variation in a global insect pest

Background  

Patterns of mtDNA variation within a species reflect long-term population structure, but may also be influenced by maternally inherited endosymbionts, such as Wolbachia. These bacteria often alter host reproductive biology and can drive particular mtDNA haplotypes through populations. We investigated the impacts of Wolbachia infection and geography on mtDNA variation in the diamondback moth, a major global pest whose geographic distribution reflects both natural processes and transport via human agricultural activities.     

稻田气体调节功能形成机制及其累积过程

生态系统服务功能在维持人类生存和发展的环境过程中发挥着重要的作用,研究生态系统服务功能形成机制以及人类活动的干扰如何影响生态系统功能和服务的实现是今后生态系统服务功能研究的一个重点。选取上海市奉贤县五四农场的一块农田生态系统,研究其气体调节功能形成和累积过程,同时研究人类干扰(施氮肥)对农田气体调节功能的影响。研究结果显示,施肥量对稻田气体调节功能形成和累积过程以及价值累积过程产生较大影响。在所有施肥处理中,施肥量最高的N 4处理提供最高的气体调节功能价值,为1.98×104yuan.hm-2。因此通过微观实验可以研究生态系统服务功能形成机制和累积过程,并可研究人类干扰造成生态系统服务功能物质量和价值量的变化。     

农田景观格局变化对昆虫的生态学效应

景观格局变化是全球变化的一个重要内容。农田是由人类赖以生存所种植的人工栽培作物组成的生态系统。在该景观系统中,多种植物-害虫-天敌相互作用、相互制约,形成有机整体。研究农田景观格局对害虫和天敌种群动态影响,不仅在害虫生物防治的实践中有重要意义,而且对于揭示人类活动对生物多样性结构与功能的影响,阐明农田景观中生物多样性整合、维持机理有重大的理论意义。本文从农田景观格局的"质、量、形、度"4个方面,系统地论述了农田景观格局变化对害虫和天敌的作用,分析了农田景观的生物控制服务功能,指出了未来研究发展的方向。