蝗虫 蝗灾 治蝗

１蝗虫蝗虫属于节肢动物门、昆虫纲、直翅目、蝗科。蝗科的种类全世界有１万多种,我国有３００多种。很多种类都是庄稼的害虫。如中华稻蝗Ｏ．ｃｈｉｎｅｎｓｉｓ,红翅重蝗,Ｐ．ｓａｕｔｅｒｉ,尤其是东亚飞蝗Ｌｏｃｕｓｔａｍｉｇｒａｔｏｒｉａｍａｎｉｌｅｎｓｉｓ...     

有关节肢动物系统发育若干问题的研究进展

近年来对节肢动物系统发育问题的认识有了相当大的变化,尤其是支序分析研究方法的使用,以及来自分子系统学和分子发育生物学的证据,成为继比较形态学之后有力的研究手段,近年来的研究显示线虫,缓步类和有爪类是节肢动物的近缘类群,而非以前绝大多数学者所认为的软体动物的环节动物,对于节肢动物门的单系性及其内部类群间关系的问题,目前倾向于认为（1）节肢动物为单系群;（2）由甲壳类,六足类和多足类联合形成单系群－具颚类;（3）与六足类分子系统学两方面研究的支持;对第3点的争议虽较大,但就论据而言确为优势观点。     

节肢动物的分类和演化

节肢动物门是动物界中最大的1个门。按新的分类系统,本门分三叶虫亚门(已灭绝)、螯肢亚门、甲壳亚门、六足亚门和多足亚门等5亚门。六足亚门相当于以前分类系统中的昆虫纲(广义的), 是最重要的一类节肢动物;此亚门分原尾纲、弹尾纲、双尾纲和昆虫纲(狭义的)等4纲;昆虫纲分3亚纲30目,包括了前昆虫纲“有翅亚纲”中的各目。为便于读者了解新、旧系统的异同,文中列举前人的代表性系统加以对照。同时,对学术界关于节肢动物的起源和演化的一些新观点予以必要的说明,对现时流行的“泛节肢动物”、“泛甲壳动物”等概念作了简要的介绍。     

常用核基因序列在双翅目昆虫系统学中的研究进展

双翅目昆虫分为长角亚目和短角亚目,前者主要类群包括蚊、蠓、蛉和蚋,后者主要类群为虻类和蝇类。国内外学者对双翅目昆虫形态分类和分子系统发育关系研究均较多。本文整理总结了几种主要核基因在双翅目昆虫进化和系统发育关系的研究资料,结果显示:双翅目的单系性得到了众多形态学、生物学和分子数据的支持,多数系统发育研究认为传统的长角亚目为并系,短角亚目是一个单系,其主要类群舞虻下目、环裂类、有缝组和有瓣蝇类均为单系,但非环裂类、无缝组为并系,无瓣类可能为并系;基本搞清了有重要医学意义和与环境关系密切的类群,特别是有瓣蝇类各科类群分类系统的进化关系;双翅目昆虫发生辐射进化的三个分支节点时间即:低等双翅目(蚊类)2.2亿年、低等短角亚目(虻类)1.8亿年、有缝组(蝇类)6500万年;大量双翅目昆虫自然生命史历经吸血性、植食性和寄生性,有2.6亿年以上的演化历程。从相关核基因研究中总结出:18SrRNA、28SrRNA和CAD基因能很好的解决高级阶元从目到属的系统发育问题;EF-1ɑ基因和White基因更适合从科到属水平的分类阶元;ITS基因一般应用在从属到种水平的低级分类阶元,并被广泛应用到双翅目昆虫分子系统学研究中。     

不同种植环境夏玉米田节肢动物群落特征及稳定性

对云南普洱不同种植环境夏玉米田节肢动物群落进行调查,应用群落特征指数、群落稳定性和主成分分析法,对不同种植环境夏玉米田节肢动物群落特征、稳定性和主成分进行对比分析。结果表明,调查区夏玉米田共采集到节肢动物10174头,隶属2纲15目100科261种,其中单作地夏玉米田采集到节肢动物共计5604头,隶属2纲13目84科168种,混交地夏玉米田采集到节肢动物共计4570头,隶属2纲15目90科209种。与单作地夏玉米田相比,混交地夏玉米田节肢动物群落物种数、多样性指数、均匀性指数、丰富度指数、天敌物种数及个体数均较高;植食性昆虫个体数及其所占比例、优势集中性指数和优势度指数较低;群落较稳定;群落多样性、均匀性、丰富度等指数随时间变化波动较小;单作地夏玉米田中,刺吸昆虫个体数量和食叶昆虫物种数量是主导节肢动物群落变化的最主要因子;混交地夏玉米田中,寄生昆虫个体数量、捕食昆虫物种数量和刺吸昆虫个体数量主导了节肢动物群落的变化。     

棉田节肢动物群落的优势种分析

优势种作为生物群落的基本特征之一 ,是指那些由于其数量多、生物量大及其在食物链中有重要地位而对群落产生重大影响的物种。但在农田昆虫群落优势种分析中 ,通常是以数量的多少而确定其是否为优势种。事实上 ,尽管有些昆虫 (如害虫 )数量不多 ,不具备群落优势种的特征 ,但由于其个体大 ,对作物造成很大的危害。对于这类昆虫是否属于优势种类目前争论较大[1,5] 。棉花 (Ｇｏｓｓｙｐｉｕｍｈｉｒｓｕｔｕｍ )是我国重要的经济作物。其内节肢动物群落物种的组成与优势程度直接影响着棉花的生产。本文拟在系统调查棉田节肢动物群落的基础上 ,…     

“节肢动物门”小结

在现行中师生物课本中,“节肢动物”一章篇幅多,内容丰富,比初中动物课本增加了昆虫纲分目及检索表等知识。“节肢动物”是动物学的重点章节,教学大纲规定要用15节课的时间完成这章的教学任务。为了使学生通过“节肢动物”一章的学习,能对整章知识加以整理、提高和系统化,归纳出节肢动物门各纲的主要特征,进一步掌握一般昆虫分类知识及其与人类的关系,从而懂得消灭害虫的方法,我在教学计划中特地安排了一节“节肢动物门”的小结课。具体做法如下:     

六足总纲系统发育研究进展与新分类系统

简要综述了昆虫分纲、分目的历史变化,包括昆虫分目多少的变化,昆虫是纲级还是总纲级阶元的变化,昆虫各目分类地位系统排列的变化以及六足总纲系统发育研究进展。根据近10年来形态特征与分子测序数据相结合的系统发育研究,整理出六足总纲与系统发育支序分析相一致的分类系统,对昆虫35目的分类运用了10个分类阶元。在此基础上,删减次要分类阶元,提出简明分类系统,既反映每个高级分类单元的单系性,明晰各目的共祖近度,又减少了分类阶元层次,方便各分类单元的识别与鉴定。六足总纲Hexapoda分为4纲:原尾纲Protura(包括蚖目Acerentomata、华蚖目Sinentomata、古蚖目Eosentomata),弹尾纲Collembola(包括弹尾目Collembola),双尾纲Diplura(包括双尾目Diplura),昆虫纲Insecta。昆虫纲分为单髁亚纲SubclassMonocondylia(包括石蛃目Archaeognatha)与双髁亚纲SubclassDicondylia。双髁亚纲分为衣鱼部DivisionZygentoma(包括衣鱼目Zygentoma)与有翅部DivisionPterygota。有翅部分为10个总目、27目。     

基于线粒体ND2基因的直翅目部分种类分子系统学发育研究

本文的研究目的是通过对直翅目部分种类的线粒体ND2基因进行分析,重建直翅目内部昆虫的系统发育关系,并探讨分子系统发育关系和传统分类结果的异同。基于80个物种ND2基因的研究结果显示直翅目ND2基因存在碱基偏向性A T含量平均为73%,第三位点A T含量79.9%最高,推测这与氨基酸变异有关。直翅目具有单系性,而蝗亚目内部的剑角蝗科、网翅蝗科、槌角蝗科和斑腿蝗科均不是单系群,锥头蝗科和瘤锥蝗科亲缘关系较近,这与Otte分类系统相一致,建议将锥头蝗科和瘤锥蝗科合并为一个科。癞蝗科的分类地位存在争议有待进一步深入的研究。     

稻田周围杂草地生境节肢动物群落的物种组成

2001年5--9月,对福建省古田县中稻田边杂草地生境的节肢动物群落,开展了系统调查,共采集到节肢动物2纲14目112科343种(或类)。其中,天敌184种(包括71种捕食性蜘蛛,31种捕食性昆虫和82种寄生性天敌),害虫52种;中性昆虫107种。     

Elongation factor-2: a useful gene for arthropod phylogenetics.

Robust resolution of controversial higher-level groupings within Arthropoda requires additional sources of characters. Toward this end, elongation factor-2 sequences (1899 nucleotides) were generated from 17 arthropod taxa (5 chelicerates, 6 crustaceans, 3 hexapods, 3 myriapods) plus an onychophoran and a tardigrade as outgroups. Likelihood and parsimony analyses of nucleotide and amino acid data sets consistently recovered Myriapoda and major chelicerate groups with high bootstrap support. Crustacea + Hexapoda (= Pancrustacea) was recovered with moderate support, whereas the conflicting group Myriapoda + Hexapoda (= Atelocerata) was never recovered and bootstrap values were always <5%. With additional nonarthropod sequences included, one indel supports monophyly of Tardigrada, Onychophora, and Arthropoda relative to molluscan, annelidan, and mammalian outgroups. New and previously published sequences from RNA polymerase II (1038 nucleotides) and elongation factor-1alpha (1092 nucleotides) were analyzed for the same taxa. A comparison of bootstrap values from the three genes analyzed separately revealed widely varying values for some clades, although there was never strong support for conflicting groups. In combined analyses, there was strong bootstrap support for the generally accepted clades Arachnida, Arthropoda, Euchelicerata, Hexapoda, and Pycnogonida, and for Chelicerata, Myriapoda, and Pancrustacea, whose monophyly is more controversial. Recovery of some additional groups was fairly robust to method of analysis but bootstrap values were not high; these included Pancrustacea + Chelicerata, Hexapoda + Cephalocarida + Remipedia, Cephalocarida + Remipedia, and Malaocostraca + Cirripedia. Atelocerata (= Myriapoda + Hexapoda) was never recovered. Elongation factor-2 is now the second protein-encoding, nuclear gene (in addition to RNA polymerase II) to support Pancrustacea over Atelocerata. Atelocerata is widely cited in morphology-based analyses, and the discrepancy between results derived from molecular and morphological data deserves greater attention.     

First molecular evidence for the existence of a Tardigrada + Arthropoda clade

The complete 18S rDNA gene sequence of Macrobiotus group hufelandi (Tardigrada) was obtained and aligned with 18S rDNA and rRNA gene sequences of 24 metazoans (mainly protostomes). Discrete character (maximum-parsimony) and distance (neighbor-joining) methods were used to infer their phylogeny. The evolution of bootstrap proportions with sequence length (pattern of resolved nodes, PRN) was studied to test the resolution of the nodes in neighbor-joining trees. The results show that arthropods are monophyletic. Tardigrades represent the sister group of arthropods (in parsimony analyses) or they are related with crustaceans (distance analysis and PRN). Arthropoda are divided into two main evolutionary lines, the Hexapoda + Crustacea line (weakly supported), and the Myriapoda + Chelicerata line. The Hexapoda + Crustacea line includes Pentastomida, but the internal resolution is far from clear. The Insecta (Ectognatha) are monophyletic, but no evidence for the monophyly of Hexapoda is found. The Chelicerata are a monophyletic group and the Myriapoda cluster close to Arachnida. Overall, the results obtained represent the first molecular evidence for a Tardigrada + Arthropoda clade. In addition, the congruence between molecular phylogenies of the Arthropoda from other authors and this obtained here indicates the need to review those obtained solely on morphological characters.      

A new view of insect-crustacean relationships II. Inferences from expressed sequence tags and comparisons with neural cladistics

The enormous diversity of Arthropoda has complicated attempts by systematists to deduce the history of this group in terms of phylogenetic relationships and phenotypic change. Traditional hypotheses regarding the relationships of the major arthropod groups (Chelicerata, Myriapoda, Crustacea, and Hexapoda) focus on suites of morphological characters, whereas phylogenomics relies on large amounts of molecular sequence data to infer evolutionary relationships. The present discussion is based on expressed sequence tags (ESTs) that provide large numbers of short molecular sequences and so provide an abundant source of sequence data for phylogenetic inference. This study presents well-supported phylogenies of diverse arthropod and metazoan outgroup taxa obtained from publicly-available databases. An in-house bioinformatics pipeline has been used to compile and align conserved orthologs from each taxon for maximum likelihood inferences. This approach resolves many currently accepted hypotheses regarding internal relationships between the major groups of Arthropoda, including monophyletic Hexapoda, Tetraconata (Crustacea + Hexapoda), Myriapoda, and Chelicerata sensu lato (Pycnogonida + Euchelicerata). "Crustacea" is a paraphyletic group with some taxa more closely related to the monophyletic Hexapoda. These results support studies that have utilized more restricted EST data for phylogenetic inference, yet they differ in important regards from recently published phylogenies employing nuclear protein-coding sequences. The present results do not, however, depart from other phylogenies that resolve Branchiopoda as the crustacean sister group of Hexapoda. Like other molecular phylogenies, EST-derived phylogenies alone are unable to resolve morphological convergences or evolved reversals and thus omit what may be crucial events in the history of life. For example, molecular data are unable to resolve whether a Hexapod-Branchiopod sister relationship infers a branchiopod-like ancestry of the Hexapoda, or whether this assemblage originates from a malacostracan-like ancestor, with the morphologically simpler Branchiopoda being highly derived. Whereas this study supports many internal arthropod relationships obtained by other sources of molecular data, other approaches are required to resolve such evolutionary scenarios. The approach presented here turns out to be essential: integrating results of molecular phylogenetics and neural cladistics to infer that Branchiopoda evolved simplification from a more elaborate ancestor. Whereas the phenomenon of evolved simplification may be widespread, it is largely invisible to molecular techniques unless these are performed in conjunction with morphology-based strategies.     

A new type of arthropod photoreceptor

A new type of photoreceptor for the phylum Arthropoda, found in the class Collembola (Arthropoda, Hexapoda) is reported. This new light-sensitive structure consists of a pair of interocular vesicles present in the genus Vesicephalus Richards, 1964 and is anatomically related to the cluster of ommatidia. The absence of a lens, the presence of a rabdome in the upper part of the vesicle and the reflection and refraction of light by a hemolymph bubble with incidence to the rhabdomeric structure are the main traits of this new photoreceptor.     

Mitochondrial genomes suggest that hexapods and crustaceans are mutually paraphyletic

For over a century the relationships between the four major groups of the phylum Arthropoda (Chelicerata, Crustacea, Hexapoda and Myriapoda) have been debated. Recent molecular evidence has confirmed a close relationship between the Crustacea and the Hexapoda, and has included the suggestion of a paraphyletic Hexapoda. To test this hypothesis we have sequenced the complete or near-complete mitochondrial genomes of three crustaceans (Parhyale hawaiensis, Squilla mantis and Triops longicaudatus), two collembolans (Onychiurus orientalis and Podura aquatica) and the insect Thermobia domestica. We observed rearrangement of transfer RNA genes only in O. orientalis, P. aquatica and P. hawaiensis. Of these, only the rearrangement in O. orientalis, an apparent autapomorphy for the collembolan family Onychiuridae, was phylogenetically informative.We aligned the nuclear and amino acid sequences from the mitochondrial protein-encoding genes of these taxa with their homologues from other arthropod taxa for phylogenetic analysis. Our dataset contains many more Crustacea than previous molecular phylogenetic analyses of the arthropods. Neighbour-joining, maximum-likelihood and Bayesian posterior probabilities all suggest that crustaceans and hexapods are mutually paraphyletic. A crustacean clade of Malacostraca and Branchiopoda emerges as sister to the Insecta sensu stricto and the Collembola group with the maxillopod crustaceans. Some, but not all, analyses strongly support this mutual paraphyly but statistical tests do not reject the null hypotheses of a monophyletic Hexapoda or a monophyletic Crustacea. The dual monophyly of the Hexapoda and Crustacea has rarely been questioned in recent years but the idea of both groups' paraphyly dates back to the nineteenth century. We suggest that the mutual paraphyly of both groups should seriously be considered.     

Phylogenetic distribution of protease inhibitors of the Kazal-family within the Arthropoda

In mammalian pancreatic cells, the pancreatic secretory trypsin inhibitor (PSTI) belonging to the Kazal-family prevents the premature activation of digestive enzymes and thus plays an important role in a protective mechanism against tissue destruction by autophagy. Although a similar protective mechanism exists in Arthropoda, the distribution of these inhibitors in this phylum remains obscure. A comprehensive in silico search of nucleotide databases, revealed the presence of members of the Kazal-family in the four major subphyla of the Arthropoda. Especially in the Hexapoda and the Crustacea these inhibitors are widespread, while in the Chelicerata and Myriapoda only a few Kazal-like protease inhibitors were found. A sequence alignment of inhibitors retrieved in the digestive system of insects revealed a conservation of the PSTI characteristics and strong resemblance to vertebrate PSTI. A phylogenetic analysis of these inhibitors showed that they generally cluster according to their order. The results of this data mining study provide new evidence for the existence of an ancient protective mechanism in metazoan digestive systems. Kazal-like inhibitors, which play an important protective role in the pancreas of vertebrates, also seem to be present in Arthropoda.     

Brain organization in Collembola (springtails)

Arthropoda is comprised of four major taxa: Hexapoda, Crustacea, Myriapoda and Chelicerata. Although this classification is widely accepted, there is still some debate about the internal relationships of these groups. In particular, the phylogenetic position of Collembola remains enigmatic. Some molecular studies place Collembola into a close relationship to Protura and Diplura within the monophyletic Hexapoda, but this placement is not universally accepted, as Collembola is also regarded as either the sister group to Branchiopoda (a crustacean taxon) or to Pancrustacea (crustaceans + hexapods). To contribute to the current debate on the phylogenetic position of Collembola, we examined the brains in three collembolan species: Folsomia candida, Protaphorura armata and Tetrodontophora bielanensis, using antennal backfills, series of semi-thin sections, and immunostaining technique with several antisera, in conjunction with confocal laser scanning microscopy and three-dimensional reconstructions. We identified several neuroanatomical structures in the collembolan brain, including a fan-shaped central body showing a columnar organization, a protocerebral bridge, one pair of antennal lobes with 20-30 spheroidal glomeruli each, and a structure, which we interpret as a simply organized mushroom body. The results of our neuroanatomical study are consistent with the phylogenetic position of Collembola within the Hexapoda and do not contradict the hypothesis of a close relationship of Collembola, Protura and Diplura.     

A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy

Traditional hypotheses regarding the relationships of the major arthropod lineages focus on suites of comparable characters, often those that address features of the exoskeleton. However, because of the enormous morphological variety among arthropods, external characters may lead to ambiguities of interpretation and definition, particularly when species have undergone evolutionary simplification and reversal. Here we present the results of a cladistic analysis using morphological characters associated with brains and central nervous systems, based on the evidence that cerebral organization is generally robust over geological time. Well-resolved, strongly supported phylogenies were obtained from a neuromorphological character set representing a variety of discrete neuroanatomical traits. Phylogenetic hypotheses from this analysis support many accepted relationships, including monophyletic Chelicerata, Myriapoda, and Hexapoda, paraphyletic Crustacea and the union of Hexapoda and Crustacea (Tetraconata). They also support Mandibulata (Myriapoda + Tetraconata). One problematic result, which can be explained by symplesiomorphies that are likely to have evolved in deep time, is the inability to resolve Onychophora as a taxon distinct from Arthropoda. Crucially, neuronal cladistics supports the heterodox conclusion that both Hexapoda and Malacostraca are derived from a common ancestor that possessed a suite of discrete neural centers comprising an elaborate brain. Remipedes and copepods, both resolved as basal to Branchiopoda share a neural ground pattern with Malacostraca. These findings distinguish Hexapoda (Insecta) from Branchiopoda, which is the sister group of the clade Malacostraca + Hexapoda. The present study resolves branchiopod crustaceans as descendents of an ancestor with a complex brain, which means that they have evolved secondary simplification and the loss or reduction of numerous neural systems.     

Evolution of identified arthropod neurons: the serotonergic system in relation to engrailed-expressing cells in the embryonic ventral nerve cord of the american lobster homarus americanus milne edwards, 1873 (malacostraca,pleocyemata, homarida)

One of the long-standing questions in zoology is that on the phylogenetic relationships within the Arthropoda. Comparative studies on structure and development of the nervous system can contribute important arguments to this discussion. In the present report, the arrangement of serotonin- and engrailed-expressing cells was examined in the embryonic ventral nerve cord of the American lobster Homarus americanus Milne Edwards, 1873 (Malacostraca, Pleocyemata, Homarida), and the spatial relationship of these two cell classes was explored by a double-labelling approach. The goal of this study was to determine whether the lobster serotonergic neurons are homologous to similar cells present in representatives of the Hexapoda and other Arthropoda. The results indicate that, in fact, these neurons in the lobster ventral nerve cord have corresponding counterparts in many other mandibulate taxa. Based on the finding of these homologies, the arrangement of serotonergic neurons in a model trunk ganglion of the mandibulate ground pattern was reconstructed as comprising an anterior and a posterior pair of serotonergic neurons per hemiganglion, each cell with both an ipsilateral and a contralateral neurite. Starting from this ground pattern, the evolutionary diversification of this class of neurons within the Mandibulata is discussed.     

Origin and differentiation of nephridia in the Onychophora provide no support for the Articulata

Comparative morphology currently permits no unambiguous decision on the primary homology of the nephridia of Annelida and Arthropoda. In order to obtain additional information on this subject, ultrastructure of morphogenesis and further differentiation of nephridia was studied in the onychophoran Epiperipatus biolleyi (Peripatidae). In this species, the nephridial anlage develops by reorganization of the lateral portion of the embryonic coelomic wall that initially gives rise to a ciliated canal. All other structural components, including the sacculus, merge after the nephridial anlage has been separated from the remaining mesodermal tissue. The nephridial sacculus does not represent a ‘persisting coelomic cavity’, since it arises de novo during embryogenesis. There is no evidence for ‘nephridioblast‘ cells participating in the nephridiogenesis of Onychophora, which is in contrast to the general mode of nephridial formation in Annelida. Available data on nephridiogenesis in euarthropods (Chelicerata, Myriapoda, Crustacea, and Hexapoda) also provide no evidence for nephridia of Annelida and Arthropoda being a synapomorphy of these taxa. These findings accordingly weaken the traditional Articulata hypothesis.