Complete mitochondrial genome of the groundhopper Alulatettix yunnanensis (Insecta: Orthoptera: Tetrigoidea)

In this work, we sequenced the first complete mitochondrial genome of Tetrigoidea species, Alulatettix yunnanensis. The circle genome (15,104 bp) consists of 13 protein-coding, 22 transfer RNA, and 2 ribosomal RNA genes, and an A+T-rich region. It has the typical invertebrate mitochondrial gene arrangement.     

The complete mitochondrial genome of cricket Sclerogryllus punctatus (Orthoptera: Gryllidae) and phylogenetic analysis

The crickets of genus Sclerogryllus Gorochov, 1985 belongs to subfamily Sclerogryllinae of family Gryllidae. In this study, we report the first complete mitogenome sequences of the genus Sclerogryllus, and analyze the features of mitogenomes of S. punctatus. The mitogenome of S. punctatus was 15,438 bp and consisted of 37 genes, coding for 13 proteins, 2 ribosomal RNA (rRNA) and 22 transfer RNA (tRNA), and a control region. S. punctatus shares the arrangement of trnE-trnS-trnN with most mitogenomes of Grylloidea. Besides, the tRNAs possess the typical cloverleaf secondary structure except for the trnS1 (AGN) gene. The phylogenetic analysis using 13 protein-coding genes and 2 rRNA represents that genus Sclerogryllus is included in subfamily Gryllinae. Our results uncover the phylogenetic position of genus Sclerogryllus by mitogenome data within the family Gryllidae.     

广西九万山地区蚱属一新种(直翅目:蚱总科)

记述采自广西九万山地区蚱科蚱属Tetrix昆虫1新种,即断隆蚱Tetrix interrupta sp.nov..该新种近似于金沙江蚱Tetrix jinshajiangensis Zheng,2001,主要区别为:(1)头顶前缘平直,不突出于复眼之前;(2)触角着生于复眼下缘之下;(3)肩部之间不具一对短纵隆线;(4)中足股节下缘近平直,密具细毛;(5)中足股节的宽度与前翅能见部分的宽度相等;(6)后足股节上侧中隆线具较大的锯齿.模式标本保存在陕西师范大学动物研究所标本室.     

The complete mitochondrial genome of Gomphocerus tibetanus Uvarov, 1935 (Orthoptera: Acrididae: Gomphocerinae)

The complete nucleotide sequence of the mitochondrial genome (mitogenome) of Gomphocerus tibetanus Uvarov, 1935 (Orthoptera: Acrididae: Gomphocerinae) was determined. It is 15,571 bp in length and contains 74.8% A + T. All Gomphocerus tibetanus protein-coding sequences start with a typical ATN codon. The usual termination codons (TAA and TAG) were found from 13 PCGs except COI and COII which took incomplete codon T as termination codons. All tRNA genes could be folded into the typical cloverleaf secondary structure, except tRNA^Ser(AGN) lacking of dihydrouridine (D) arm. The sizes of the large and small ribosomal RNA genes are 1313 and 822 bp, respectively. The A + T content of the A + T-rich region is 82.3%. A preliminary analysis on characteristics of Gomphocerinae mitogenome was made by comparision among three Gomphocerinae mitogenomes and Locusta migratoria.     

A preliminary mitochondrial genome phylogeny of Orthoptera (Insecta) and approaches to maximizing phylogenetic signal found within mitochondrial genome data

The phylogenetic utility of mitochondrial genomes (mtgenomes) is examined using the framework of a preliminary phylogeny of Orthoptera. This study presents five newly sequenced genomes from four orthopteran families. While all ensiferan and polyneopteran taxa retain the ancestral gene order, all caeliferan lineages including the newly sequenced caeliferan species contain a tRNA rearrangement from the insect ground plan tRNA(Lys)(K)-tRNA(Asp)(D) swapping to tRNA(Asp) (D)-tRNA(Lys) (K) confirming that this rearrangement is a possible molecular synapomorphy for this suborder. The phylogenetic signal in mtgenomes is rigorously examined under the analytical regimens of parsimony, maximum likelihood and Bayesian inference, along with how gene inclusion/exclusion, data recoding, gap coding, and different partitioning schemes influence the phylogenetic reconstruction. When all available data are analyzed simultaneously, the monophyly of Orthoptera and its two suborders, Caelifera and Ensifera, are consistently recovered in the context of our taxon sampling, regardless of the optimality criteria. When protein-coding genes are analyzed as a single partition, nearly identical topology to the combined analyses is recovered, suggesting that much of the signals of the mtgenome come from the protein-coding genes. Transfer and ribosomal RNAs perform poorly when analyzed individually, but contribute signal when analyzed in combination with the protein-coding genes. Inclusion of third codon position of the protein-coding genes does not negatively affect the phylogenetic reconstruction when all genes are analyzed together, whereas recoding of the protein-coding genes into amino acid sequences introduces artificial resolution. Over-partitioning in a Bayesian framework appears to have a negative effect in achieving convergence. Our findings suggest that the best phylogenetic inferences are made when all available nucleotide data from the mtgenome are analyzed simultaneously, and that the mtgenome data can resolve over a wide time scale from the Permian (approximately 260 MYA) to the Tertiary (approximately 50 MYA).     

云南东部蚱属一新种记述（直翅目：蚱总科：蚱科）

记述采自云南东部地区蚱属1新种,即南盘江蚱Tetrix nanpanfiangensis,sp．nov．。该新种近似于桂北蚱Tetrix guibeiensis Zheng,Lu and Li,2000,主要区别为本新种：1）侧观头顶与颜面隆起成直角形;2）颜面隆起在侧单眼处略凹陷;3）前胸背板前缘平直：4）侧观背板上缘肩前弧形,其后平直;5）肩部不具1对短纵隆线;6）第1跗节下之第3垫大于第1、2垫。新种与丁氏蚱Tetrix tinkhami Zheng et Liang,1998也近似,但新种后翅不到达后突的顶端,中足股节宽度明显狭于前翅宽。 正模：♂,云南陆良县,25．1°N,103．8°E,2000m,2006-Ⅷ-10,邓维安采;副模：3♂♂,9♀♀,同正模;3♂♂,3♀♀,云南沾益县,25．6°N,103．8°E,2000m,2006-Ⅷ-12,邓维安采：4♂♂,4♀♀,云南宣威市,26．2°N,104．1°E,2000m,2006-Ⅷ-14,邓维安采。 模式标本保存在陕西师范大学动物研究所标本室（7♂♂10♀♀）和河池学院动物标本室（3♂♂7♀♀）。     

The complete mitochondrial genome of Parafronurus youi (Insecta: Ephemeroptera) and phylogenetic position of the Ephemeroptera

The first complete mitochondrial genome of a mayfly, Parafronurus youi (Arthropoda: Insecta: Pterygota: Ephemeroptera: Heptageniidae), was sequenced using a long PCR-based approach. The genome is a circular molecule of 15,481 bp in length, and encodes the set of 38 genes. Among them, 37 genes are found in other conservative insect mitochondrial genomes, and the 38(th) unique gene is trnM-like (trnM2). The duplication-random loss model can be used to explain one of the translocations at least. The A+T content of the control region is 57%, the lowest proportion detected so far in Hexapoda. Based on the nucleotide dataset and the corresponding amino acid dataset of 12 protein-coding genes, Bayesian inference and maximum likelihood analyses yielded stable support for the relationship of the three basal clades of winged insects as Ephemeroptera+(Odonata+Neoptera).     

The complete mitochondrial genome of Eriocheir japonica sinensis (Decapoda: Varunidae) and its phylogenetic analysis

The complete mitochondrial genome (mitogenome) can provide novel insights into understanding the mechanisms underlying mitogenome evolution. In this study, the complete mitogenome of Eriocheir japonica sinensis (Decapoda: Varunidae) was determined to be 16,378 bp, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a D-loop region. The AT skew of the E. j. sinensis mitogenome was slightly negative (−0.016), indicating a higher number of T compared with A nucleotides. The nucleotide composition of the mitogenome was also biased toward A + T nucleotides (71.6%). All PCGs were initiated by ATN codons. Eight of the 13 PCGs harbored the incomplete termination codon by T, or TA. All other tRNA genes displayed a typical clover-leaf structure of mitochondrial tRNA. The D-loop region of the E. j. sinensis mitogenome was 918 bp in length. Based on 13 PCGs, phylogenetic analysis confirmed the placement of E. j. sinensis within the Varunidae.     

中国蚱属二新种记述(蚱总科:蚱科)

记述采自云南省蚱属昆虫二新种,即南贡山蚱（Tetrix nangongshanensis sp．nov．）及大理蚱（Tetrix daliensis sp．nov）。模式标本保存于陕西师范大学动物研究所昆虫标本室。     

The complete mitochondrial genome of Tonkinacris sinensis(Orthoptera: Acrididae): A tRNA-like sequence and its implications for phylogeny

The complete mitochondrial genome of Tonkinacris sinensis is 15,627 bp long and contains13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes and one A + T-rich region. The gene order and orientation are identical to those of other Orthoptera species, containing the rearrangement of trnD and trnK. Intriguingly, a tRNA^Ser-like gene exists on the N strand between the trnSUCN and nad1 genes. The length of this gene is 110 bp, and it has a typical clover-leaf structure, an anticodon, and a high cove score (23.49). On its clover-leaf structure, on the anticodon arm, there is a 41 bp intron with an unknown function. Here, phylogenetic analysis was conducted based on 13 PCGs of 30 species from 9 subfamilies of Acrididae to understand their phylogenetic relationships. According to the phylogenetic tree, the relationship among the 9 subfamilies within Acrididae was as follows: (Spathosterninae + (Oxyinae + (Catantopinae + (Calliptaminae + (Cyrtacanthacridinae + (Melanoplinae + (Gomphocerinae + (Oedipodinae + Acridinae)))))))).     

The mitochondrial genome of the entomophagous endoparasite Xenos vesparum (Insecta: Strepsiptera)

In this study, the nearly complete sequence (14,519 bp) of the mitochondrial DNA (mtDNA) of the entomophagous endoparasite Xenos vesparum (Insecta: Strepsiptera) is described. All protein coding genes (PCGs) are in the arrangement known to be ancestral for insects, but three tRNA genes (trnA, trnS(gcu), and trnL(uag)) have transposed to derived positions and there are three tandem copies of trnH, each of which is potentially functional. All of these rearrangements except for that of trnL(uag) is within the short span between nad3 and nad4 and there are numerous blocks of unassignable sequence in this region, perhaps as remnants of larger scale predisposing rearrangements. X. vesparum mtDNA nucleotide composition is strongly biased toward A and T, as is typical for insect mtDNAs. There is also a significant strand skew in the distribution of these nucleotides, with the J-strand being richer in A than T and in C than G, and the N-strand showing an opposite skew for complementary pairs of nucleotides. The hypothetical secondary structure of the LSU rRNA has also been reconstructed, obtaining a structural model similar to that of other insects.     

Prepulse inhibition of the startle reaction in the locust Locusta migratoria (Insecta: Orthoptera: Acridoidea)

A fast startle reaction of unrestrained sitting locusts (Locusta migratoria) can be elicited by sound pulses of steep rise time above 80 dB. The reaction consists of a fast jerky movement of legs and body with a mean latency of 35 ms and graded amplitude. The fast startle reaction did not result in any positional change; this was in contrast to acoustically induced escape reactions of flying Orthoptera. The startle reaction could be inhibited by pure tone stimuli of much lower intensity (60 dB) presented 160 ms before the startle-eliciting noise. This type of reflex modification is a striking convergence to the well-known prepulse inhibition of the mammalian startle response where it has been used to assess sensory thresholds. In the locust, prepulses between 3 and 20 kHz suppressed the startle reaction completely, with thresholds in the locust's hearing range as known from tympanal nerve recordings. No inhibition could be observed at prepulse frequencies of 40 kHz, although this frequency lies within the locust's hearing range. The presence of prepulse inhibition in an invertebrate preparation shows that it is not restricted to vertebrates.     

Morphometrics reveal correlation between morphology and bioclimatic factors and population mixture in Tetrix japonica (Orthoptera: Tetrigidae)

The morphology of an organism is limited by genetic and environmental factors, and the precise mechanism is inconsistent between species. Tetrix japonica Bolivar, 1987, is a widely distributed pygmy grasshopper in East Asia. However, the population clustering and relationships between the morphology and bioclimatic factors have not been previously investigated. Here, 32 geographic populations were sampled from China, and morphometrics and multiple statistical analyses were applied to detect the population clustering and relationship between the morphology and bioclimatic factors. The results suggested that T. japonica with females are significantly bigger than males in the eight morphological traits. The 32 populations do not obviously cluster according to the natural geographic area. The body sizes of females are mainly related to the lowest temperature and precipitation; by contrast, males only have a significant relationship with the lowest temperature. The forewing size is significantly related to the maximum precipitation. Furthermore, the Mantel test showed that the morphological size variation of females has a weak positive correlation to geographic distance, but is insignificant in males. It was concluded that Chinese geographic populations of T. japonica mixed and that the size of the morphological structure is limited by bioclimatic factors.     

The complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae)

In this paper, we determined the complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae). The whole mitogenome of S. strictus is 16,535?bp in length with a base composition of 21.7% A, 41.0% T, 25.6% C, and 11.7% G and contains 12 protein-coding genes (atp8 is missing), 2 ribosomal RNA genes, 22 transfer RNA genes, and a major non-coding region (MNR). Some peculiar patterns including tandem repeats and microsatellite-like elements are found in the MNR of S. strictus.     

虱目裂化线粒体基因组研究进展

虱目是哺乳类和鸟类体表的专性寄生虫。在虱科、阴虱科、长角鸟虱科和兽羽虱科的某些寄生虱种中发现了线粒体基因组裂化现象, 其线粒体基因组裂化成了多个环状的线粒体染色体, 如体虱(Pediculus humanus)、头虱(pediculus capitis)和阴虱(Pthirus pubis)的线粒体基因组分别裂化形成20个、20个和14个微环染色体。微环染色体可能是基因删除和同源重组的结果, 关于线粒体基因组裂化的具体原因和机制, 目前并不清楚, 推测可能是进化选择或随机遗传漂变的结果或与线粒体单链DNA结合蛋白的缺失有关。鉴于线粒体基因组裂化研究对于深入理解线粒体的起源和进化方面具有重要意义, 文章以虱目裂化线粒体基因组为主线, 列举了动物裂化线粒体基因组和裂化特征, 阐述了虱目裂化线粒体基因组的研究现状, 分析了虱目线粒体基因组裂化的类型、原因和机制, 并对该领域未来的研究方向进行了展望。     

云斑车蝗线粒体基因组全序列测定与分析

采用长距 PCR 扩增及保守引物步移法并结合克隆测序测定并注释了云斑车蝗 Gastrimargus marmoratus （Thunberg）的线粒体基因组全序列。结果表明：云斑车蝗线粒体基因组全序列为15 904 bp（GenBank登录号为EU527334）,A+T含量略高于非洲飞蝗Locusta migratoria,为76.04%,包括13个蛋白质编码基因,22个tRNA 基因,2个rRNA基因和一段1 057 bp的A+T富集区。蛋白质基因的起始密码子中,除COⅠ和ND5为TTG以外,均为昆虫典型的起始密码子ATN。ND5基因使用了不完全终止密码子T,其余基因均为典型的TAA或TAG。预测了22个tRNA基因的二级结构,发现tRNA^Ser（AGN）缺少DHU臂, tRNA^Ser（UGY）的反密码子环上有9个碱基。预测了云斑车蝗12S和16S rRNA二级结构,分别包括3个结构域30个茎环和6个结构域44个茎环。A+T富集区含有3个串联重复序列。     

Complete mitochondrial genome of Oxya chinensis （Orthoptera, Acridoidea）

The complete sequence of Oxya chinensis （0. chinensis） mitochondrial genome is reported here. It is 15,443 bp in length and contains 75.9% A＋T. The protein-coding genes have a similar A＋T content （75.2%）. The initiation codon of the cytochrome oxidase subunit I gene in the mitochondrial genome of O. chinensis appears to be ATC, instead of the tetranucleotides that have been reported in Locusta migratoria （L migratoria） mitochondrial genome. The sizes of the large and small ribosomal RNA genes are 1319 and 850 bp, respectively. The transfer RNA genes have been modeled and showed strong resemblance to the dipteran transfer RNAs, and all anticodons are identical to those of dipteran. The A＋T-rich region is 562 bp, shorter than that of other known Orthoptera insects. The six conserved domains were identified within the A＋T-rich region by comparing its sequence with those of other grasshoppers. The result of phylogenetic analysis based on the dataset containing 12 concatenated protein sequences confirms the close relation-ship of O. chinensis with L migratoria.