天敌昆虫抗药性研究进展

天敌昆虫抗药性研究在协调害虫化学防治和生物防治中有着重要的理论和现实意义,其研究的最终目的在于更好地推进抗性天敌在害虫综合治理(IPM)中的应用。抗药性天敌昆虫具有潜在的巨大价值。鉴于此,本文系统地综述了天敌昆虫抗药性最新研究进展,包括杀虫剂对天敌昆虫的影响、天敌昆虫抗药性现状、抗药性机理和限制天敌昆虫抗药性发展因素等。文章最后还对抗药性天敌昆虫的应用前景进行了展望。     

苏铁蚧虫及其天敌

通过对我省10县市的调查、采集和鉴定,苏铁蚧虫计有15种,隶属4科、10属。发生最普遍、最严重的是咖啡盔蚧和酱褐圆蚧。天敌有寄生性天敌15种、捕食性天敌6种和寄生菌1种。     

植物-害虫-天敌互作机制研究前沿

植物-害虫-天敌之间的三级营养互作关系是当今进化生态学和化学生态学研究领域的前沿课题,也是寻找害虫可持续控制途径的重要基础。自2006年以来,我国昆虫学家在973项目《重大农业害虫猖獗危害的机制及可持续控制》的支持下,围绕害虫、植物、天敌协同进化机理的关键科学问题,以棉花-害虫-天敌、水稻-害虫-天敌和蔬菜-害虫-天敌系统为研究对象开展研究,发现OsHI-LOX参与虫害诱导的水稻茉莉酸(JA)信号途径合成,并通过水稻对二化螟和褐飞虱不同抗性作用的调控;寄主植物烟草受到棉铃虫和烟青虫危害后将被诱导产生化学防御作用,但它们的作用不同;绿叶挥发物(3Z)-hexen-ol是寄生蜂天敌定位寄主的最关键化合物,植物-害虫-天敌之间的互作关系受到光周期和CO2浓度升高而改变;植物对害虫直接的防御和通过寄生蜂对害虫的间接防御存在"权衡"关系;转基因棉花种植加重了盲椿象灾变。这些研究成果在Science,New Phytology,Plant Journal,Plant,Cell and Environment等刊物上发表论文150余篇,极大地提高了我国在作物-害虫-天敌三者之间关系的研究水平。     

Trichomes of Lycopersicon species and their hybrids: effects on pests and natural enemies

1 The cultivated tomato, Lycopersicon esculentum, is an economically important worldwide crop. Current pest management techniques rely heavily on pesticides but trichome‐based host‐plant resistance may reduce pesticide use. 2 A review of the literature is provided on trichomes of wild Lycopersicon species and the effects of trichome‐based host‐plant resistance on arthropods. Solvents have been used to remove glandular trichome exudates and the resulting dimminution of their effects quantified. Correlational approaches to assess the relationship between the different trichome types and effects on pests have also been used. 3 Most studies have focused on Lepidoptera and Hemiptera, although some work has included Coleoptera, Diptera and Acarina, and both antibiotic and antixenotic effects have been demonstrated. 4 Natural enemies are a cornerstone of international pest management and this review discusses how the compatibility of this approach with trichome‐based host‐plant resistance is uncertain because of the reported negative effects of trichomes on one dipteran, one hemipteran and several Hymenoptera. 5 For trichome‐based host‐plant resistance to be utilized as a pest management tool, trichomes of wild species need to be introgressed into the cultivated tomato. Hybrids between the cultivated tomato and the wild species Lycopersicon hirsutum f. glabratum, Lycopersicon pennellii and Lycopersicon cheesmanii f. minor have been produced and useful levels of resistance to Acarina, Diptera and Hemiptera pests have been exhibited, although these effects may be tempered by effects on natural enemies. 6 This review proposes that studies on genetic links between fruit quality and resistance, field studies to determine the compatibility of natural enemies and trichome‐based host‐plant resistance, and a strong focus on L. cheesmanii f. minor, are all priorities for further research that will help realize the potential of this natural defence mechanism in pest management.     

Interaction effects between local flower richness and distance to natural woodland on pest and beneficial insects in apple orchards

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Trichomes of Lycopersicon species and their hybrids: effects on pests and natural enemies

1 The cultivated tomato, Lycopersicon esculentum, is an economically important worldwide crop. Current pest management techniques rely heavily on pesticides but trichome‐based host‐plant resistance may reduce pesticide use. 2 A review of the literature is provided on trichomes of wild Lycopersicon species and the effects of trichome‐based host‐plant resistance on arthropods. Solvents have been used to remove glandular trichome exudates and the resulting dimminution of their effects quantified. Correlational approaches to assess the relationship between the different trichome types and effects on pests have also been used. 3 Most studies have focused on Lepidoptera and Hemiptera, although some work has included Coleoptera, Diptera and Acarina, and both antibiotic and antixenotic effects have been demonstrated. 4 Natural enemies are a cornerstone of international pest management and this review discusses how the compatibility of this approach with trichome‐based host‐plant resistance is uncertain because of the reported negative effects of trichomes on one dipteran, one hemipteran and several Hymenoptera. 5 For trichome‐based host‐plant resistance to be utilized as a pest management tool, trichomes of wild species need to be introgressed into the cultivated tomato. Hybrids between the cultivated tomato and the wild species Lycopersicon hirsutum f. glabratum, Lycopersicon pennellii and Lycopersicon cheesmanii f. minor have been produced and useful levels of resistance to Acarina, Diptera and Hemiptera pests have been exhibited, although these effects may be tempered by effects on natural enemies. 6 This review proposes that studies on genetic links between fruit quality and resistance, field studies to determine the compatibility of natural enemies and trichome‐based host‐plant resistance, and a strong focus on L. cheesmanii f. minor, are all priorities for further research that will help realize the potential of this natural defence mechanism in pest management.     

Additive effects of predator diversity on pest control caused by few interactions among predator species

1. Studies of the impact of predator diversity on biological pest control have shown idiosyncratic results. This is often assumed to be as a result of differences among systems in the importance of predator–predator interactions such as facilitation and intraguild predation. The frequency of such interactions may be altered by prey availability and structural complexity. A direct assessment of interactions among predators is needed for a better understanding of the mechanisms affecting prey abundance by complex predator communities. 2. In a field cage experiment, the effect of increased predator diversity (single species vs. three‐species assemblage) and the presence of weeds (providing structural complexity) on the biological control of cereal aphids were tested and the mechanisms involved were investigated using molecular gut content analysis. 3. The impact of the three‐predator species assemblages of aphid populations was found to be similar to those of the single‐predator species treatments, and the presence or absence of weeds did not alter the patterns observed. This suggests that both predator facilitation and intraguild predation were absent or weak in this system, or that these interactions had counteracting effects on prey suppression. Molecular gut content analysis of predators provided little evidence for the latter hypothesis: predator facilitation was not detected and intraguild predation occurred at a low frequency. 4. The present study suggests additive effects of predators and, therefore, that predator diversity per se neither strengthens nor weakens the biological control of aphids in this system.     

多作稻田生态系统对稻纵卷叶螟及其天敌功能团的影响

为探明稻田与非稻田生境时空配置对稻纵卷叶螟Cnaphalocrocis medinalis (Guenée)及其天敌功能团产生的生态学效应,分别于2007和2008年的中稻期,在福建省武夷山试验基地,采用室内观察法、田间剥查法和吸虫器法,系统调查了水稻多作系统和水稻单作系统内稻纵卷叶螟种群及其寄生蜂功能团和捕食性节肢动物个体数量的时序动态; 同时通过陷阱诱集法,调查了多作和单作稻田生境边界地表捕食性节肢动物（蜘蛛和昆虫）个体数量的时序动态,以及多作系统中,捕食性节肢动物在稻田和非稻田生境间的迁移动态。 结果表明：与辣椒、生姜、玉米和花生等镶嵌种植的稻田,其稻纵卷叶螟幼虫及其寄生蜂功能团个体数量较单一稻田差异不大,而捕食性节肢动物则明显少于单作稻田,但多作稻田边界较单作稻田边界有更多的捕食性节肢动物个体数量（2007年：多作稻田边界1984~2294个体,单作稻田边界1479个体;2008年：多作稻田边界3 417~4 178个体,单作稻田边界2 423个体）。 究其原因,主要由于多作系统中捕食性节肢动物更偏好从稻田向非稻田生境迁移,其中捕食性昆虫效应更明显。     

The effects of natural enemies,competition, and host plant water availability on an aphid population

Summary I used a factorial experiment repeated in two years to assess the relative effects of natural enemy attack, interspecific competition, and water availability to the host plant, and of interactions among these factors, on the population dynamics of the aphid Aphis varians feeding on fireweed (Epilobium angustifolium). The impact of a suite of coccinellid and syrphid predators emerged as the predominant factor affecting the success of aphid colonies: colonies protected from natural enemies grew in size at a rate of ten percent per day, were only one tenth as likely to go extinct, and produced over ten times more dispersing alates. In contrast, I found only minor effects of removing flea beetles, the most abundant herbivore with which A. varians colonies cohabit fireweed stems, and of supplementing water availability to fireweed host plants, in spite of a significant effect of watering frequency on aphid growth in the green-house. There was no evidence of significant two- or three-way interactions among factors. Hence, despite the potential complexity of the food web in which it is embedded, the dynamics of A. varians appears to be driven predominantly by a single factor, i.e. interactions with natural enemies.     

Interactive effects of species richness and species traits on functional diversity and redundancy

The importance of species diversity for ecosystem function has emerged as a key question for conservation biology. Recently, there has been a shift from examining the role of species richness in isolation towards understanding how species interact to effect ecosystem function. Here, we briefly review theoretical predictions regarding species contributions to functional diversity and redundancy and further use simulated data to test combined effects of species richness, number of functional traits, and species differences within these traits on unique species contributions to functional diversity and redundancy, as well as on the overall functional diversity and redundancy within species assemblages. Our results highlighted that species richness and species functional attributes interact in their effects on functional diversity. Moreover, our simulations suggested that functional differences among species have limited effects on the proportion of redundancy of species contributions as well as on the overall redundancy within species assemblages, but that redundancy rather was determined by number of traits and species richness. Our simulations finally indicated scale dependence in the relative effects of species richness and functional attributes, which suggest that the relative influence of these factors may affect individual contributions differently compared to the overall ecosystem function of species assemblages. We suggest that studies on the relationship between biological diversity and ecosystem function will benefit from focusing on multiple processes and ecological interactions, and that the relative functional attributes of species will have pivotal roles for the ecosystem function of a given species assembly.     

Monitoring of wheat insects and their natural enemies using sticky traps in wheat

Beneficial arthropods and wheat insects were monitored using sticky traps through large-scale field in Saxony, Germany before and after insecticide applications. The tested compounds (Karate, Biscaya and NeemAzal T/S) were sprayed twice at Elongation stage (GS 32) and at the heading stage (GS 55). Monitoring was conducted for four weeks after each treatment. Cereal aphids, thrips, leafhoppers, cereal leaf beetles, cereal bugs and also many natural enemies such as predators (lady beetles, lacewings, syrphids, dance flies and spiders) and parasitoids (parasitic wasps) were surveyed. The results proved that Karate caused the highest per cent mortality to wheat insect pests. Karate also reduced natural enemy diversities. Biscaya and NeemAzal T/S is correlated with an equivalent mortality per cents to wheat insect pests and resulted in a smaller effects on natural enemies compared with Karate. Leafhoppers were less affected than Thrips and cereal bugs. Parasitoid wasps and spider were more tolerant, while lacewings and dance flies were more susceptible to insecticide effects. Finally, natural insecticides and predators and parasitoids could be highly compatible with a hygienic environment.     

Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California

Aim Several studies have found that more accurate predictive models of species’ occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the data used to train the model. We examined the effect of model type, species rarity class, species’ survey frequency, detectability and manipulated sample prevalence on the accuracy of distribution models developed for 30 reptile and amphibian species. Location Coastal southern California, USA. Methods Classification trees, generalized additive models and generalized linear models were developed using species presence and absence data from 420 locations. Model performance was measured using sensitivity, specificity and the area under the curve (AUC) of the receiver‐operating characteristic (ROC) plot based on twofold cross‐validation, or on bootstrapping. Predictors included climate, terrain, soil and vegetation variables. Species were assigned to rarity classes by experts. The data were sampled to generate subsets with varying ratios of presences and absences to test for the effect of sample prevalence. Join count statistics were used to characterize spatial dependence in the prediction errors. Results Species in classes with higher rarity were more accurately predicted than common species, and this effect was independent of sample prevalence. Although positive spatial autocorrelation remained in the prediction errors, it was weaker than was observed in the species occurrence data. The differences in accuracy among model types were slight. Main conclusions Using a variety of modelling methods, more accurate species distribution models were developed for rarer than for more common species. This was presumably because it is difficult to discriminate suitable from unsuitable habitat for habitat generalists, and not as an artefact of the effect of sample prevalence on model estimation.     

襄北农作物害虫天敌及其优势种的初步调查

198 9年 ,作者曾对襄北农作物害虫天敌进行了系统调查和研究 ,并初步查明襄北地区农田天敌资源及其优势种类[1] 。此后由于长期大量使用化学农药防治害虫 ,使农田天敌数量减少 ,生态平衡遭到破坏 ,致使害虫再度猖獗 ,农药残毒严重超标 ,农产品质量下降 ,危及人类健康。根据这种情况 ,近年来湖北襄北农场通过大力推广生物农药 ,保护利用天敌昆虫等生物防治措施 ,使农田生态环境得到改善 ,天敌昆虫的种群数量也比以前有较大幅度的增长。为了摸清现阶段农田天敌的优势种类 ,以便更好地为保护利用提供理论依据 ,作者于 2 0 0 1～ 2 0 0 2年对襄…     

Landscape context and management effects on an important insect pest and its natural enemies in almond

Pest control mediated by organisms such as parasitoids is a valuable ecosystem service, particularly with regard to high costs, low effectiveness, and detrimental effects of some agrochemicals. This study examined infestation rates and abundance of pests and their natural enemies in organic and conventional almond orchards in California, differing in landscape context, understory plant cover, and plant species richness. Parasitoids of the commercially most important insect pest of almond, the Navel Orangeworm (NOW) were studied by rearing NOW in collected overwintering nuts. The indirect impact of vertebrate natural enemies of NOW were estimated by counting empty nut shells with feeding marks by wild birds and various mammals, found at the orchard floor. Mean nut infestation by NOW ranged from 0.8% to 37% per orchard and was reduced by parasitism rates, ranging from 0% to 22%, and vertebrate nut damage, ranging from 2% to 96% per orchard. The parasitoids were facilitated by a high proportion of natural habitat surrounding the orchards and high proportion of understory ground cover with vegetation. The vertebrate natural enemies were facilitated by a high proportion of natural habitat surrounding the orchards and plant species richness in the orchard understory. In conclusion, this study shows that pest control mediated by vertebrates and invertebrates promoted by near natural habitats can lower pest pressure by NOW larvae in overwintering almond. In case of the vertebrate nut damage this service might only be temporal and turn into a dis-service during and after harvest because the vertebrates continue to feed on the nuts and may also cause injuries to the trees.     

Comparison of pollinators and natural enemies: a meta‐analysis of landscape and local effects on abundance and richness in crops

To manage agroecosystems for multiple ecosystem services, we need to know whether the management of one service has positive, negative, or no effects on other services. We do not yet have data on the interactions between pollination and pest‐control services. However, we do have data on the distributions of pollinators and natural enemies in agroecosystems. Therefore, we compared these two groups of ecosystem service providers, to see if the management of farms and agricultural landscapes might have similar effects on the abundance and richness of both. In a meta‐analysis, we compared 46 studies that sampled bees, predatory beetles, parasitic wasps, and spiders in fields, orchards, or vineyards of food crops. These studies used the proximity or proportion of non‐crop or natural habitats in the landscapes surrounding these crops (a measure of landscape complexity), or the proximity or diversity of non‐crop plants in the margins of these crops (a measure of local complexity), to explain the abundance or richness of these beneficial arthropods. Compositional complexity at both landscape and local scales had positive effects on both pollinators and natural enemies, but different effects on different taxa. Effects on bees and spiders were significantly positive, but effects on parasitoids and predatory beetles (mostly Carabidae and Staphylinidae) were inconclusive. Landscape complexity had significantly stronger effects on bees than it did on predatory beetles and significantly stronger effects in non‐woody rather than in woody crops. Effects on richness were significantly stronger than effects on abundance, but possibly only for spiders. This abundance‐richness difference might be caused by differences between generalists and specialists, or between arthropods that depend on non‐crop habitats (ecotone species and dispersers) and those that do not (cultural species). We call this the ‘specialist‐generalist’ or ‘cultural difference’ mechanism. If complexity has stronger effects on richness than abundance, it might have stronger effects on the stability than the magnitude of these arthropod‐mediated ecosystem services. We conclude that some pollinators and natural enemies seem to have compatible responses to complexity, and it might be possible to manage agroecosystems for the benefit of both. However, too few studies have compared the two, and so we cannot yet conclude that there are no negative interactions between pollinators and natural enemies, and no trade‐offs between pollination and pest‐control services. Therefore, we suggest a framework for future research to bridge these gaps in our knowledge.     

Mechanisms underpinning climatic impacts on natural populations: altered species interactions are more important than direct effects

Shifts in species' distribution and abundance in response to climate change have been well documented, but the underpinning processes are still poorly understood. We present the results of a systematic literature review and meta‐analysis investigating the frequency and importance of different mechanisms by which climate has impacted natural populations. Most studies were from temperate latitudes of North America and Europe; almost half investigated bird populations. We found significantly greater support for indirect, biotic mechanisms than direct, abiotic mechanisms as mediators of the impact of climate on populations. In addition, biotic effects tended to have greater support than abiotic factors in studies of species from higher trophic levels. For primary consumers, the impact of climate was equally mediated by biotic and abiotic mechanisms, whereas for higher level consumers the mechanisms were most frequently biotic, such as predation or food availability. Biotic mechanisms were more frequently supported in studies that reported a directional trend in climate than in studies with no such climatic change, although sample sizes for this comparison were small. We call for more mechanistic studies of climate change impacts on populations, particularly in tropical systems.     

西沙群岛礁栖鱼类物种多样性及其食性特征

通过新的方法(即潜水调查法)调查了西沙群岛浅水区的礁栖鱼类, 并从食性角度分析鱼类群落特征及其对水质环境变化的响应。2006年5-6月, 对西沙群岛6个岛礁(东岛、永兴岛、羚羊礁、金银岛、华光礁和中建岛)共10个站位的礁栖鱼类种类、数量和长度进行了调查, 结合公开资料(FishBase等)确定鱼类食性。共记录到29科71属119种鱼, 其中50种是新记录。至此, 西沙群岛的鱼类总记录已达到717种。从不同站位来看, 永兴岛西的种类数量和Shannon-Wiener多样性指数均最高。多数鱼种分布范围狭小。摄食浮游动物和底栖无脊椎动物的鱼类是优势类群, 而草食性、杂食性和食物链顶端食性的鱼类数量和生物量较低, 反映出西沙群岛珊瑚礁生态系统整体上健康稳定。永兴岛的杂食性鱼类的数量比例和生物量比例均高于其他岛礁, 反映出鱼类群落已对水体富营养化产生响应。