基于线粒体COⅡ基因的中国蝽科分子系统学研究(半翅目,异翅亚目)

扩增并测定了我国蝽科4亚科8属11种昆虫线粒体COⅡ基因585 bp的序列,对序列的碱基组成、转换颠换、遗传距离等进行分析,探讨了COⅡ基因在该科的分子进化机制.并基于COⅡ基因序列数据,分别采用邻接法(NI)、最大简约法(MP)和贝叶斯推论法(BI)建立蝽科分子系统发育关系.研究结果表明,蝽科昆虫COⅡ基因A T含量平均为71.7%,存在较强的A T含量偏向性,氨基酸的变异率为27.2%;亚科间的遗传距离介于0.168～0.242之间,大于亚科内属种间的遗传距离,蝽科与盾蝽科2外群之间遗传距离最大,两科之间存在明显的间断.分子系统发育树表明,短喙蝽亚科为蝽科中较为原始的类群,分化较早,益蝽亚科与舌盾蝽亚科关系较近,形成一对姐妹群,蝽科中捕食性种类--益蝽亚科是较为特化的类群,它是由植食性种类分化而来.蝽科4亚科间的分子系统发育关系为Phyllocephalinae (Pentatominae (Asopinae Podopinae).     

基于线粒体Cyt b基因和CO I基因序列研究豹蛱蝶亚科(鳞翅目,蛱蝶科)10属间的系统发生关系

测定了国产豹蛱蝶亚科10属共10个代表种的Cyt 6基因和CO Ⅰ基因的部分序列.结合从GenBank中获得的3个种类CO Ⅰ基因的同源序列,以锯眼蝶亚科2个物种为外群,通过遗传分析软件对CO Ⅰ、Cyt b独立基因序列和联合基因序列以及编码的氨基酸序列进行了比较分析,同时用邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和贝叶斯法(BI)重建分子系统树,分析了该亚科10个属之间的系统发生关系.结果显示:1)联合基因序列的A+T平均含量为71.90h,具A、T偏倚性,其编码的357个氨基酸中没有半胱氨酸,变异率为11.5%;2)豹蛱蝶亚族为单系群;3)青豹蛱蝶属和豹蛱蝶属间、黄襟蛱蝶属和珐蛱蝶属间具有较近的亲缘关系;4)支持将文蛱蝶属、襟蛱蝶属和珐蛱蝶属从豹蛱蝶亚科中分离出来.     

基于MTDNA序列的中国臭蚁亚科(膜翅目,蚁科)分子系统学研究

通过对臭蚁亚科7属16种昆虫(凹头臭蚁属philidris因未采集到除模式标本以外的标本,故未包含在其中)线粒体DNA的COⅠ、COⅡ和Cyt b基因部分序列(1 801 bp)进行测定,并从GeneBank下载Leptomyrmex unicolor相应基因片段序列,以江华多刺蚁Polyrhachis jianghuaensis和聚纹双刺猛蚁Diacamma rugosum作外群,重建了中国臭蚁亚科系统发育关系.研究结果支持(狡臭蚁属Technomyrmex+(酸臭蚁属Tapinoma+光胸臭蚁属Liometopum)的关系,虹臭蚁属Iridomyrmex+凹臭蚁属Ochetellus为姐妹群,强烈支持臭蚁属Dolichoderus的单系性,8种臭蚁的遗传关系稳定:((((((平背臭蚁D.flatidorsus+黑腹臭蚁D.taprobanae)+(皱头臭蚁D.rugocapitus+费氏臭蚁D.feae)+双疣臭蚁D.thoracicus)+凹头臭蚁D.incisus)+西伯利亚臭蚁D.sibiricus)+毛臭蚁D.pilosus).系统发育树显示细臭蚁属Leptomyrmex在臭蚁亚科进化过程中的分类地位不确定,没有与同族的虹臭蚁属和凹臭蚁属聚在一起,而是与穴臭蚁属Borhriomyrmex聚在一起互为姐妹群,这与传统的形态分类观点不一致,还有待于进一步研究.     

基于COⅠ基因的中国广头叶蝉亚科系统发育初探

广头叶蝉亚科Macropsinae广泛分布于世界各地,其内部分类系统较混乱,部分族属级分类地位一直存在争议。本文选取23种叶蝉样本(内群22种+外群1种),分析其线粒体COⅠ基因部分片段的序列组成和遗传距离,基于最大似然法和贝叶斯法构建广头叶蝉亚科系统发育树。结果发现,COⅠ基因片段序列A+T含量(68. 3%)明显较G+C含量(31. 7%)高;遗传距离在种间、属间和亚科间的差异有统计学意义;系统发育树较好地支持了横皱叶蝉属Oncopsis和尖尾叶蝉属Pedionis的单系性,但广头叶蝉属Macropsis和暗纹叶蝉属Pediopsoides较为混乱。     

基于线粒体COⅠ基因的沙鳅亚科鱼类DNA条形码及其分子系统发育研究

选择线粒体COⅠ基因作为分子标记,进行沙鳅亚科鱼类（Botiinae）DNA条形码及其分子系统发育研究。研究获得了沙鳅亚科7属19种共131个个体的COⅠ基因序列,利用MEGA5.0软件分析了沙鳅亚科鱼类COⅠ基因的序列特征,计算了种内及种间遗传距离。沙鳅亚科鱼类的分子系统发育关系的重建分别采用NJ法和Bayesian法。研究发现,沙鳅亚科COⅠ基因的碱基组成为: A 24.4%、T 29.5%、G 18.0%、C 28.1%。沙鳅亚科鱼类种内平均遗传距离为0.0020.000,种间平均遗传距离为0.1480.008。DNA条形码研究结果显示,所分析的19种沙鳅鱼类各自分别聚成单系分支,表明COⅠ基因在本研究中具有100%的物种鉴别率。同时,系统发育分析支持各属的单系性,并且结果显示沙鳅亚科鱼类聚为两个分支,其中一支由薄鳅属和副沙鳅属构成,另一分支则包括: （沙鳅属、色鳅属）和 中华沙鳅属、（缨须鳅属、安彦鳅属）。因此,COⅠ基因可以作为有效的分子标记对沙鳅亚科进行DNA条形码研究以及分子系统发育研究。       

中国黄粉蝶亚科六属间基于COⅡ和EF-1α基因部分序列的系统发育关系（鳞翅目：粉蝶科）

为了探讨中国黄粉蝶亚科属间的系统发育关系,我们对其中6属9种的细胞色素氧化酶Ⅱ（COⅡ）的部分序列和延伸因子基因（EF-1α）部分序列进行了分析。分别采用最大简约法（maximum parsimony, MP）、最大似然法（maximum likelihood, ML）和贝叶斯推论法（bayesian inference, BI）构建黄粉蝶亚科分子系统树。结果表明：在测得的COⅡ基因的648 bp序列和EF-1α基因的504 bp序列中,有261个变异位点,151个简约信息位点,黄粉蝶亚科内各属COⅡ基因A+T含量（77.3%）均明显偏高。系统发育分析显示黄粉蝶属为亚科中较为原始的类群,分化较早,豆粉蝶属和迁粉蝶属亲缘关系较近,但钩粉蝶属与豆粉蝶属、迁粉蝶属之间的亲缘关系还不能确定。本研究结果和传统的基于形态学的黄粉蝶亚科的分类体系有所不同,最显著的分歧是本研究支持内群中分化最早的属应为黄粉蝶属,而不是豆粉蝶属和迁粉蝶属。     

墨天牛属昆虫COⅠ基因比较及系统学初步研究

【目的】对11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对墨天牛属系统发育关系进行初步探讨。【方法】本文测定分析了11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了墨天牛属的分子进化树。【结果】序列比对分析得到470 bp大小的COⅠ基因片段,其中可变异位点169个(36.0%),保守位点301个(64.0%),转换/颠换的平均值(R值)为1.03,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对墨天牛属昆虫的分子系统进化关系进行探讨。结果显示分子结果与形态分类结果相似。【结论】利用COⅠ基因构建的墨天牛属系统发育树是探讨墨天牛分类的有效方法。     

中国库蚊属四十个种(亚种)的分子系统发育关系研究(双翅目:蚊科)

【目的】对在中国有分布的库蚊属Culex种(亚种)的COⅠ序列和ITS2序列进行测序,构建和讨论这些种(亚种)的分子系统发育关系。【方法】测定了库蚊属20个种(亚种)的COⅠ和ITS2序列,并从NCBI数据库中下载了库蚊属另外20个种(亚种)的COⅠ和3个种(亚种)的ITS2序列。对库蚊属40个种(亚种)的COⅠ序列和其中23个种(亚种)的ITS2序列进行碱基构成、种间遗传距离和饱和度分析,并对COⅠ+ITS2序列进行ILD(incongruence length difference)检验。分别使用2种分子数据集(COⅠ和ITS2)的核苷酸序列,用最大似然法(ML)、贝叶斯法(BI)、邻接法(NJ)和最大简约法(MP)推断这些种的系统发育关系。通过Kishino-Hasegawa(KH)和ShimodairaHasegawa(SH)检验评估这4种系统树间的差异,确定最为合理的系统发育树。【结果】本研究新测序获得20种(亚种)的COⅠ和ITS2序列的长度范围分别为625~685 bp和300~559 bp。COⅠ和ITS2序列在库蚊属成对蚊种间的遗传距离分别是0.002~0.198和0.006~1.807。库蚊属23个种(亚种)的COⅠ+ITS2序列的ILD检验结果显示,数据集具有不相容性,因此COⅠ+ITS2序列不适用于这些种(亚种)的系统发育研究。经KH和SH检验显示,4种系统发育树中,基于COⅠ序列构建的BI树最为合理,而基于ITS2序列构建的MP树最为合理。基于COⅠ核苷酸序列所构建的BI树显示,除幼小库蚊Cx.infantulus和短须库蚊Cx.brevipalpis外,各亚属间成员聚类结果与传统的形态学归类结果吻合;路蚊亚属Lutiza和包蚊亚属Barraudius都归入库蚊亚属Culex内;梅蚊亚属Maillotia和新库蚊亚属Nexoculex聚为一支;库状蚊亚属Culiciomyia、真黑蚊亚属Eumelanomyia和簇角蚊亚属Lophoceramyia均显示为单系。基于ITS2序列所构建的MP树显示,各亚属间和种(亚种)间关系混乱。【结论】重建的分子系统发育树表明库蚊亚属不是一个单系群。在重建库蚊属系统发育关系时,相较于ITS2和COⅠ+ITS2,COⅠ是更为理想的分子标记。本研究构建的分子系统发育关系为中国库蚊属中各亚属和各种(亚种)之间的亲缘关系的研究奠定了基础。     

基于COⅡ基因序列的斑腿蝗科部分亚科的分子系统学研究

采用PCR产物直接测序法测定了斑腿蝗科10个亚科16属22种的COⅡ基因585 bp的片段, 对序列的碱基组成进行了分析,并评估了数据集的系统发育信号;最后,以癞蝗科的肃南 短鼻蝗作为外群,采用NJ法、MP法、ML法以及贝叶斯推论法构建了系统树,以解决这些物种所代表的亚科之间的系统发育关系。结果表明：22种斑腿蝗科昆虫的COⅡ基因序列碱基组成表现强烈的A+T含量偏向性。对COⅡ基因585 bp序列片段构成的全数据组和根据密码子不同位点划分的密码子第一、第二和第三位点数据组的系统发育信号分析显示,所有数据组都具有一定的系统发育信息。在4种方法得到的合一树中发现： （1）星翅蝗亚科、刺胸蝗亚科、黑背蝗亚科、斑腿蝗亚科的亲缘关系较近;（2）卵翅蝗亚科与稻蝗亚科亲缘关系较近,建议卵翅蝗亚科似乎应归入稻蝗亚科中,板胸蝗亚科与这两个亚科的关系较近;（3）黑蝗亚科和秃蝗亚科似乎应合并为一个亚科;（4）切翅蝗亚科的4个属未聚在一起,表明这些属的区别较大,不是一个单系群;（5）黑蝗亚科和秃蝗亚科关系较近,且与本研究中其他几个亚科的亲缘关系相对较远。研究结果表明COⅡ基因在解决斑腿蝗科的亚科以下属种间的系统发育关系时是一个有效的分子标记。     

斑皮蠹属昆虫COⅠ基因比较及系统学初步研究

对6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对斑皮蠹属系统发育关系进行初步探讨。本研究测定分析了6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了斑皮蠹的分子进化树。序列比对分析得到365 bp大小的COⅠ基因片段,其中可变异位点182个(49.9%),保守位点174个(47.7%),转换/颠换的平均值(R值)为0.9,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对斑皮蠹属昆虫的分子系统进化关系进行探讨。研究显示分子结果与形态分类结果相似。利用COⅠ基因构建的斑皮蠹系统发育树是探讨斑皮蠹系统学的有效方法。     

A molecular framework for the phylogeny of the ant subfamily dolichoderinae

Partial sequences are reported for the mitochondrial genes for cytochrome oxidase subunits 2 and 3 and for cytochrome b, and the entire sequence of the gene for tRNA(Leu)(UUR) for species from 14 genera of dolichoderine ants and from three outgroup genera. Considerable variation was observed between tRNA genes in the size of the TPsiC arm and the DHU and anticodon loops and whether or not the TPsiC stem possesses a GC pair. The outgroup taxa showed complete TAA CO1 stop codons, but dolichoderines have either TA or T. The outgroup taxa showed a noncoding gap between the CO1 and the tRNA(Leu)(UUR) genes. A phylogeny-independent compatibility test using the amino acid sequences showed differences between the genes consistent with variation in evolutionary rates, according with other studies. Base compositions proved heterogeneous between species, hence phylogenetic analysis was restricted to the protein sequences using maximum likelihood and the mtREV24 replacement matrix. A maximum-likelihood consensus tree has similarities to those from morphological studies with some exceptions such Leptomyrmex falling within the dolichoderine genera rather than basally, and the accretion of genera formerly included under Iridomyrmex. Features of the tRNA genes and the CO1 termination codons agree quite well with the molecular phylogeny.     

A combined molecular approach to phylogeny of the jumping spider subfamily dendryphantinae (araneae: salticidae)

Four gene regions were sequenced for 30 species of jumping spiders, most from the subfamily Dendryphantinae, to investigate their molecular phylogeny and evolution. These are three regions from the mitochondria (ca. 560 bp of 16S plus adjacent tRNA, 1047 bp of cytochrome oxidase 1 (CO1), and 414 bp of NADH1 (ND1) and one region from the nuclear genome (ca. 750 bp of 28S). Parsimony and likelihood analyses of these gene regions separately and together support the monophyly of the dendryphantines as delimited previously by morphological characters. A group of elongate-bodied genera are placed as basal among the dendryphantines, and previously proposed relationships of Poultonella, Paraphidippus, and Sassacus vitis are confirmed. Comparison of overall rates of molecular evolution indicates striking differences across the gene regions, with highest divergence in ND1, CO1, 16S, and 28S in decreasing order. All four regions are characterized by both within- and among-site rate variation. Phylogenetic results from CO1 conflict conspicuously with phylogenetic results from the other genes and morphological data. Attempts to account for potential sources of this conflict (e.g., accommodating biased base composition, high homoplasy, within- and among-site rate variation, etc.) are largely unsuccessful.     

A molecular phylogeny of the tribe Aphidini (Insecta: Hemiptera: Aphididae) based on the mitochondrial tRNA/COII, 12S/16S and the nuclear EF1α genes

Abstract A phylogeny of the tribe Aphidini (Hemiptera: Aphididae) was reconstructed from three gene fragments: two mitochondrial regions, partial tRNA‐leucine + cytochrome oxidase II (tRNA/COII), partial 12S rRNA + tRNA‐valine + 16S rRNA (12S/16S) and one nuclear gene, the elongation factor‐1 alpha (EF1α). Bayesian phylogenetic (BP) analyses were performed on each individual dataset of tRNA/COII, 12S/16S and EF1α, and maximum parsimony (MP), Bremer support test, maximum likelihood (ML) and BP analysis were performed on the combined dataset. After comparing our molecular phylogenetic results with the classic classification based on morphological and ecological data, we analysed three main issues: the monophyletic relationships among tribes and subtribes, the validities of the latest taxonomic positions of genera and species and the status of certain Aphis species groups. Our results indicate that 36 of the species analysed, with the exception of Cryptosiphum artemisiae, are clustered within the clade of Aphidini. Also, the 28 species representative of the subtribe Aphidina were separated from the eight species representative of Rhopalosiphina; each monophyletic subtribe was supported by significant P‐values in the combined analysis. According to our results, Cryptosiphum should be moved to Macrosiphini because it is more closely related to the genera Lipaphis and Brevicoryne. The genus Toxoptera was recovered as non‐monophyletic. In Rhopalosiphina, three genera, Hyalopterus, Rhopalosiphum and Schizaphis, were relatively closer to each other than to the genus Melanaphis. In the relationships between species‐groups among Aphis, most species were separated into two main lineages; the fabae group seemed to be more closely related to the spiraecola and craccivora group rather than to the gossypii group.     

基于28S rDNA D2基因片段与形态特征的优茧蜂亚科系统发育研究

本研究选取优茧蜂亚科Euphorinae(膜翅目Hymenoptera:茧蜂科Braconidae)的8族19属23种作为内群,茧蜂其它6个亚科的8属8种作外群,首次结合同源核糖体28S rDNA D2基因序列片段和41个形态学特征对该亚科进行了系统发育学研究。利用"圆口类"的内茧蜂亚科Rogadinae、茧蜂亚科Braconinae、矛茧蜂亚科Doryctinae的3个亚科为根,以PAUP*4.0和MrBayes3.0B4软件分别应用最大简约法(MP)和贝叶斯法对优茧蜂亚科的分子数据和分子数据与非分子数据的结合体进行了分析;并以PAUP*4.0对优茧蜂亚科的28S rDNA D2基因序列的片段的碱基组成与碱基替代情况进行了分析。结果表明:优茧蜂亚科的28S rDNA D2基因序列片段的GC%含量在40.00%~49.25%之间变动,而对于碱基替代情况来讲,优茧蜂亚科各个成员间序列变异位点上颠换(transversion)大于转换(transition);不同的分析和算法所产生的系统发育树都表明目前根据形态定义出的优茧蜂亚科Euphorinae不是一个单系群,而是一个与蚁茧蜂亚科Neoneurinae和高腹茧蜂亚科Cenocoelinae混杂在一起的并系群;在优茧蜂亚科内部,悬茧蜂族Meterorini和食甲茧蜂族Microctonini(排除猎户茧蜂属Orionis)为单系群,而宽鞘茧蜂族Centistini、大颚茧蜂族Cosmophorini、优茧蜂族Euphorini、瓢虫茧蜂族Dinocampini为并系群;悬茧蜂族Meterorini在优茧蜂亚科Euphorinae内位于基部位置的观点得到部分的支持,同时食甲茧蜂族Microctonini被判定为相对进化的类群。此外对于优茧蜂亚科内各属之间的相互亲缘关系,不同算法所得到的系统发育属的结果不完全一致,这表明优茧蜂亚科内(属及族)的系统发育关系还有待于进一步研究。     

COⅡ基因在昆虫分子系统学研究中的作用和地位

细胞色素氧化酶Ⅱ(cytochromeoxidaseⅡ,COⅡ)基因位于线粒体DNA(mtDNA)上,编码细胞色素氧化酶亚基Ⅱ,该亚基为细胞色素c提供重要的结合位点。COⅡ基因进化速率较快,是昆虫分子系统学研究中理想的分子标记。目前,已经利用该基因从各个分类水平对昆虫系统发育关系、物种形成与分化、种群遗传与变异及生物地理等方面做了广泛的研究。研究表明,利用该基因可以很好地解决昆虫属、种及种下分类单元的系统发育问题,但是在解决科、亚科等高级阶元的系统发育关系时仍存在一些局限,COⅡ基因与其他mtDNA及核基因的联合分析能够更好地解决昆虫的系统发育问题。     

Grazers, shredders and filtering carnivores--the evolution of feeding ecology in Drusinae (Trichoptera: Limnephilidae): insights from a molecular phylogeny

We examined the phylogenetic relationships between species and genera within the caddisfly subfamily Drusinae (Trichoptera: Limnephilidae) using sequence data from two mitochondrial loci (cytochrome oxidase 1, large subunit rRNA) and one nuclear gene (wingless). Sequence data were analysed for 28 species from five genera from the subfamily. We analysed individual and combined data sets using a Bayesian Markov Chain Monte Carlo and a maximum parsimony approach and compared the performance of each partition for resolving phylogenetic relationships at this level. In terms of resolution and phylogenetic utility wingless outperformed the two mitochondrial gene partitions. Using both Shimodaira-Hasegawa and expected likelihood weights tests we tested several hypotheses of relationships previously inferred based on adult morphological characters. The data did not support the generic concept, or many previously proposed species groupings, based on adult morphology. In contrast, the molecular data correlated with the morphology and feeding ecology of larvae. Using Bayesian ancestral character state reconstructions we inferred the evolution of feeding ecology and relevant larval morphological characters. Our analyses showed that within the subfamily Drusinae two derived feeding types evolved. One of these--grazing epilithic algae--is otherwise unusual in the Limnephilidae and may have promoted the high degree of diversity in the Drusinae.     

基于28S rDNA D2基因片段与形态特征的矛茧蜂亚科系统发育研究（膜翅目：茧蜂科）

本研究选取矛茧蜂亚科Doryctinae（昆虫纲Insecta：膜翅目Hymenoptera：茧蜂科Braconidae）的6族15属18种做内群,茧蜂科其它7亚科11属11种做外群,首次结合同源核糖体28S rDNA D2基因序列片段和100个形态学和解剖学特征对该亚科进行了系统发育学研究。利用“非圆口类"的小腹茧蜂亚科Microgastrinae为根,以PAUP*4.0和MrBayes 3.0B4软件分别应用最大简约法（MP）和贝叶斯法对矛茧蜂亚科的分子数据和分子数据与非分子数据的结合体进行了运算分析;并以PAUP*4.0对矛茧蜂亚科的28S rDNA D2基因序列片段的碱基组成与碱基替代情况进行了分析。结果表明：矛茧蜂亚科的28S rDNA D2基因序列片段的GC含量在39.33%～48.28%之间变动,而对于碱基替代情况来讲,矛茧蜂亚科各成员间序列变异位点上颠换（transversion）大于转换（transition）。不同的分析算法所产生的系统发育树都表明矛茧蜂亚科是一个界限分明的单系群;在矛茧蜂亚科内,除了吉丁茧蜂族Siragrini为单系群外,其他族（矛茧蜂族Doryctini和方头茧蜂族Hecabolini）都是并系群。对于矛茧蜂亚科内各属之间的相互亲缘关系,不同算法所得的系统发育树的拓扑结构不完全一致,表明矛茧蜂亚科内（属及族）的系统发育关系还有待于进一步研究。     

The ant subfamily Pseudomyrmecinae (Hymenoptera: Formicidae): generic revision and relationship to other formicids

Three genera are recognized in the ant subfamily Pseudomyrmecinae: Myrcidris new genus (monotypic; type species M. epicharis , new species, from Amazonas, Brazil); Pseudomyrmex Lund (c. 150 nominal taxa; southern Nearctic and Neotropical regions); and Tetraponera F. Smith (c. 110 nominal taxa; Palaeotropical region). New generic synonymies are: Pseudomyrmex Lund = Ornatinoda Enzmann = Clavanoda Enzmann = Triangulinoda Enzmann = Apendunculata Enzmann = Latinoda Enzmann; and Tetraponera F. Smith = Pachysima Emery = Viticicola Wheeler = Sima Emery (nee Roger) = Parasima Donisthorpe. Autapomorphies are identified for the subfamily and for its constituent genera, indicating the monophyly of all four taxa. Based on available character-state information, Myrcidris is most parsimoniously interpreted as a sister-group to all other Pseudomyrmecinae {Pseudomyrmex + Tetraponera) , although there is almost equally strong support for an alternative grouping: Tetraponera + (Myrcidris + Pseudomyrmex). Phylogenetic relationships of the Pseudomyrmecinae and other ant subfamilies within the 'poneroid complex' ( sensu Taylor, 1978) were assessed by a cladistic analysis of eleven representative ant genera. At the level of subfamily relationships the results suggest that: (1) The Myrmicinae and the Pseudomyrmecinae are sister groups. (2) Within the 'poneroid complex' is an unresolved trichotomy composed of: (i) Pseudomyrmecinae + Myrmicinae, (ii) Myrmeciinae, and (iii) Ponerinae + Leptanillinae + (Cerapachyinae + Dorylinae (s.l.)). (3) The Nothomyrmeciinae are a basal lineage within the 'poneroid complex', rather than being allied with the 'formicoid complex' (Formicinae, Dolichoderinae and Aneuretinae).     

Molecular characterization and phylogenesis of Steganinae (Diptera, Drosophilidae) inferred by the mitochondrial cytochrome c oxidase subunit 1

The subfamily Steganinae (Diptera, Drosophilidae) includes flies which display zoophilic feeding behaviour in the larval and/or adult stages, some of which act as vectors of Spirurida eyeworms, which infect both carnivores and humans. To date, the taxonomy and phylogeny of the subfamily Steganinae has been studied only superficially and many aspects of their systematics remain unresolved. Thus, the present study aimed to provide a molecular dataset to facilitate the identification and phylogenetic analysis of Steganinae species based on partial ( approximately 700 basepairs) mitochondrial cytochrome c oxidase subunit 1 (cox1) sequences. A total of 134 flies belonging to 13 species and eight genera of Steganinae were subjected to molecular and phylogenetic analyses. The mean nucleotide variation within the Steganinae subfamily was 8.1%, with a variation within genera for which more than one species was examined ranging from 1.6% (in Phortica spp.) to 21.8% (in Amiota spp.). Interspecific pairwise divergence ranged from 1.6% (Phortica variegata vs. Phortica semivirgo) to 24.8% (Cacoxenus indagator vs. Amiota alboguttata) and intraspecific variation ranged from 0% to 1%. Seventy of the 233 amino acids were variable, including 26 parsimony informative sites and 44 singleton sites, with some highly conserved residues identified within the genera Stegana and Amiota. Parsimony and maximum likelihood-based phylogenetic analyses provided strong support for the genus Phortica, phylogenetically distinct from the genus Amiota. Gitona distigma was placed in an unresolved position adjacent to the outgroup taxa, Drosophila yakuba and Drosophila melanogaster. The molecular data reported here represent the first molecular dataset based on cox1 of Steganinae flies and provide a base for further investigations into the evolutionary relationships among this little-studied subfamily.