四平转山湖水库地区昆虫多样性的初步研究

昆虫个体虽小,但种类繁多,全世界约有140万种生物,而昆虫约占53.57%.昆虫与人类有着极为密切的关系,如害虫对人类健康和国民经济有着重要影响,但绝大多数种类的昆虫对人类是有益或中性的,有的是显花植物的传粉者;有的是害虫的天敌;生活在土壤内的昆虫能促进腐殖质形成与土壤通气,提高土地的肥力;而有些昆虫的产物,如蜂蜜、丝、白蜡等是食品、医药及工业原料;还有许多昆虫用于环境净化和科学研究等多个领域[1].     

二化螟饲养方法的研究

植食性昆虫的人工饲养,近年来日益引起重视,根据 Singh(1977)的总结,约有 754种重要害虫可用人工饲料饲养,而有些种类已达到大量生产应用的水平。人工饲养主要根据两方面的需要:一是用来研究基础理论课题,如研究昆虫的营养生理、昆虫生态、昆虫毒理等;二是用来研究害虫的防治与益虫的利用,如研究杀虫剂、不孕剂、昆虫激素、性诱剂、辐射不育,或培养害虫的天敌等;都需要不受地区或季节的限制而获得大量标准化的试虫。     

害虫的苏云金杆菌（Bt）控制

各种害虫对人类的影响的确令人头痛。科学家们已经使用多种办法企图控制它——化学的、物理的、生物的、微生物的。苏云金杆菌的研究与利用可能是最明智的选择。昆虫与人类的生产和生活有着极其密切的关系,就其对人们的生产活动和日常生活的影响来说,可分为有害昆虫(即害虫)和有益昆虫两大类。如天敌昆虫赤眼蜂可用于防治夜蛾、粉蝶、玉米螟等农业害虫,而逐腐趋臭的苍蝇、吸吮人畜血液的蚊蚋,对人类的影响是众所周知的。人类在同大自然的斗争中,自然对有益的昆虫加以保护和利用,     

棉露尾甲——一种有利用前景的传粉昆虫

传粉昆虫(pollinatiors)的种类很多,国内外研究较多的主要集中在膜翅目和双翅目,如传统的传粉昆虫蜜蜂、壁蜂、熊蜂、切叶蜂、大头金蝇和食蚜蝇等[1],而关于鞘翅目昆虫作为传粉昆虫的报道很少.棉露尾甲Haptoncus luteolus(Erichson)属鞘翅目露尾甲科,国内将其记载为仓储害虫[2]和棉花害虫[3],未见其作为传粉昆虫的报道.传粉昆虫来到花上是要获取食物,同时也起到了传授花粉的作用[4].作者还观察到棉露尾甲有较特殊的携带花粉的构造和携带花粉的能力(另文发表).本文通过对棉露尾甲在棉花不同类型花上的分布、扩散以及寄主范围等的调查以证明其传粉作用和利用前景.     

不同光源和暗适应时间对棉铃虫蛾趋光行为的影响

1　引　　言诱虫灯是监测昆虫迁飞、扩散、发生期和发生量的重要工具 ,也是害虫综合治理的重要措施之一 .一般认为 ,昆虫飞向光源是一种趋光行为 ,但国内外很多学者认为这种行为是光源对昆虫正常活动的干扰 ,并非是昆虫的趋性[4 ].昆虫对不同波长的光源反应不同 .丁岩钦[6 ]对棉铃虫蛾 (Helicover paarmigera)进行了 1 3种单色光的行为选择实验 ,最高峰在333nm ;侯无危等[9]对桃小食心虫 (Carposinaniponensis)的趋光性研究发现 ,其对 333nm以上的单色光均有趋光反应 .魏国树等[12～ 14 ]在 340～ 6 0 5nm波谱范围内测定了棉铃虫蛾的行为反…     

具保幼激素活性的昆虫生长调节剂应用前景展望

随着对常现杀虫剂不良作用的认识日益深刻,人类对杀虫剂的理解和认识也发生了根本性的变化,不仅要求有效地控制害虫,而且更注重生物合理性或环境和谐性;日趋强调对害虫的种群进行控制和调节（regulation）,而不是“杀死”[1]。在昆虫生理学、生物化学和分子生物学等相关学科迅速发展的推动下,昆虫毒理学有关害虫防治机理的研究不断取得突破和进展。同时对节肢动物内分泌机理的不断了解,更进一步促进了生物合理性农药（biorahonalpestiddes）的研究设计与开发,具保幼激素活性的昆虫生长调节剂（insectgrowthregulator,IGR)便是其成…     

寄生蜂寄主选择行为研究进展

寄生蜂是膜翅目昆虫中的重要类群,在自然界种类多,数量大。据文献报道全世界膜翅目昆虫大约有10万种”’,其中许多种类与农林害虫长期保持一定的制约关系,在害虫防治中占有重要地位。由于大量使用化学农药导致害虫的抗药性增加,利用天敌昆虫来防治害虫越来越显示出其重要性和优越性。但是,直到近20年来,寄生蜂的寄生行为才受到重视,并给予了广泛的、深入的研究”－‘’严格地讲,寄生蜂应该称为拟寄生蜂,它与通常所说的寄生昆虫像虱子、臭虫等有明显不同,主要区别在于：1．寄生仅仅发生在未成熟阶段,而成虫阶段营自由生活;2．寄…     

谈农林害虫的自然控制

人类的发展面临着许多问题,其中包括环境污染与害虫暴发失控等, 对策应是人类谋求与自然协调共存。人类必须学会既要和众多的非生命物又要和数千万种生物包括100多万种昆虫协调共存。天敌昆虫是大害虫的克星; 人类赖以生存的经济植物是由昆虫传播花粉的; 昆虫是人类的美味佳肴和医病良药; 有些昆虫是重要工业原料。所以人类要锐意合理利用昆虫资源。对于农林害虫要尽可能谋求自然控制; 提倡利用植物的抗害性、利用害虫的天敌、利用昆虫生长调节剂、种间信息物质、昆虫辐射不育技术控制害虫。尽量利用植物性杀虫剂控制害虫。尽量采用不杀伤或少杀伤天敌、不污染环境的化学杀虫剂或方法防治害虫。我国创造了很多行之有效的利用农业技术防治害虫的方法。     

昆虫分布南界的形成原因及影响因素

生物都有一定的适生区,低温导致其分布北界的形成是不争的事实,然而一些种类还存在分布上的南界。昆虫的生长发育与环境的关系非常密切,研究其分布南界的形成原因对预测昆虫种群的扩散和暴发具有重要意义。从环境、寄主和人类活动等方面总结了北半球昆虫分布南界形成的机制及影响因素。低纬度地区夏季高温引起昆虫死亡率上升、生殖率下降、昆虫体内共生菌解体和冬季低温过高导致昆虫滞育节律被破坏等是昆虫分布南界形成的主要原因。此外,寄主的分布和人类活动也对昆虫分布南界存在一定影响。气候变暖对不同种类昆虫的分布南界影响不同,大部分昆虫的分布范围会扩大,但一些受环境限制的昆虫分布南界往往北移。建议今后对全球气候变暖背景下昆虫分布南界的变化、检疫性害虫在其原产地和入侵地分布南界的差异及其原因进行研究,以期为分析昆虫分布的变化提供依据,也为害虫防治提供新的可能途径。     

玉米地节肢动物群落优势功能集团的组成与演替

近年来 ,对于农作物害虫的研究 ,不再局限于单个害虫的发生规律 ,而偏向于对昆虫群落的研究 ,因为群落是联结种群与生态系统之间的桥梁。对有害生物的综合治理 ,也更加注重对群落结构的影响 ,而不是只考虑某一特定有害生物的本身[9] 。研究和分析节肢动物群落的结构特征 ,对于控制害虫的种群变动及进行综合治理有重要的意义。金翠霞等运用种类丰富度 (ｓ)、均匀性 (ｖ′)和申农系数 (ｓｈａｎｎｎｏｎｉｎｄｅｘＨ′)分析了稻田节肢动物群落和各亚群落多样性的空间层次差异 ,季节动态以及杀虫剂对群落结构的影响[5] 。郝树广等把稻田节肢动…     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.