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Ladybird beetles (Coleoptera: Coccinellidae), with broad morphological diversity, wide geographic distribution and substantial agricultural significance, are a challenging group for taxonomists and phylogenetics. As a promising tool to identify and discover new species, DNA barcoding might offer significant potential for identification, taxonomy and phylogeny of ladybird beetles. In the present study, a total of 1364 COI (cytochrome C oxidase subunit I) sequences representing 128 species from 52 genera of ladybird beetles were screened for barcoding evaluation and phylogenetic analysis. Our results from the barcoding analysis revealed that COI displays a similar level of species identification efficiency (nearly 90%) either based on Kimura two-parameter (K2P) distances calculation or on simplified neighbour-joining (NJ) tree construction. The phylogenetic relationships within the family Coccinellidae was analyzed by Bayesian-inference (BI) method. The phylogenetic results confirmed the monophyly of the subfamilies Microweisinae and Coccinellinae sensu Ślipiński (2007), and suggested that the subfamilies Coccidulinae, Chilocorinae and Scymninae are paraphyletic. However, the phylogenetic relationships among different subfamilies are not clearly defined and thus remain to be thoroughly studied. Overall, our study confirmed the usefulness of DNA barcoding for coccinellid species identification and phylogenetic inference. [ABSTRACT FROM AUTHOR]

DNA barcoding has been widely used to identify and discover new species in a wide range of taxa. In order to assess the effectiveness of COI (cytochrome C oxidase subunit I) and 16S (16S ribosomal RNA) in the discrimination of spiders, we have generated 289 barcodes for a total of 56 farmland spider species from 14 different families for the first time in China. Our results reveal that the standard barcoding marker COI can be used to distinguish the farmland spiders both in species and family level by NJ tree-based method, despite the absence of a barcode gap between the intra- and inter-specific genetic divergences. 16S has a lower species identification success as compared with COI. However, almost 98% of the species can be correctly distinguished for both COI and 16S when a threshold of 3% nucleotide divergence was used for species discrimination. Our study significantly improves the barcode reference sequence library for Chinese farmland spiders, and will be very useful in pest management and eco-environmental monitoring and protection. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the wolf spiderWadicosa fideliswas determined. It is a circular molecule of 14,741 bp in length and contains a standard set of 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs and a control region. The A + T content of the overall base composition of majority strand (J-strand) is 76.1% (T: 43.0%; C: 8.2%; A:33.1%; G: 15.7%). Start codons in all 13 protein-coding genes (PCGs) follow the ATN rule, except of four genes (COII, COII, ND4andND6), which have TTG start codon. The usual termination codons (TAA and TAG) are found from nine PCGs. However,COI, ND1, ND4L, ND5had an incomplete termination codon (T). The control region (D-loop) is 1071 bp long with 67.9% A + T content, and contains a long tandem repeat region, which is comprising three full 215 bp copies and a partial fourth (87 bp) copy. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of an orb-weaving spiderNeoscona theisi(Walckenaer) is determined in this article. It is a typical circular duplex DNA molecule with a length of 14,156 bp, which encodes the same 37 genes as all metazoan mitogenomes and an A + T-rich region (D-loop). The overall A + T content is 75.2% (A: 35.5%; T: 39.8%; G: 15.6%; C: 9.3%). All of the protein-coding genes were initiated by ATN, with the exceptions in three genes.COIhas a TTA start codon,COII, COIIIandND6use TTG as initiation codon. Three genes (ND3, COIIandND5) end with incomplete stop codons (T or TA), while all other genes terminated with canonical stop codons (TAA or TAG). Among 22 transfer RNAs genes, six of them (tRNAAla, tRNASer(AGN), tRNASer(UCN), tRNAGly, tRNAArgandtRNAHis) lack the potential to form the cloverleaf-shaped secondary structure. The A + T-rich region is 559 bp with an A + T content of 79.6%. [ABSTRACT FROM AUTHOR]

The complete mitogenomes ofCyrtarachne nagasakiensisandHypsosinga pygmaeaare determined to be 14,402 and 14,193 bp in length, with the A + T content of 75.7% and 76.1%, respectively. All protein-coding genes in both spiders start with the initiation codons (ATT, ATA, TTA or TTG) that are usually used in Araneae mitogenomes, and terminate with canonical stop codon TAA or TAG except forND5in both spiders andND4LinH. pygmaea, which end with the incomplete codon TA or T instead. Most of the tRNAs lack the potential to form the typically cloverleaf-shaped secondary structures and none of tandem repeats are present in the control regions of both spider mitogenomes. The phylogenetic analysis based on the Bayesian inference dataset shows a good resolution of relationship ofC. nagasakiensisandH. pygmaeain Araneidae. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of an orb-weaver spiderCyclosa argenteoalbais determined in this article. The genome encodes the same 37 genes with a length of 14,575 bp as all other metazoan mitogenomes. The A + T content of the majority strand is 73.1%. Among the protein-coding genes, one gene (COI) begins with TTA, three (COII, COIIIandND6) start with ATT, three (ATP6, ND3andND4) begin with ATA and other six genes use ATT as initiation codon. All the protein-coding genes end with the canonical termination codons (TAA or TAG), except forND3andND4L, which use an incomplete stop codon (T). Thirteen transfer RNAs genes lack the potential to form the cloverleaf-shaped secondary structure. The A + T-rich region is 1052 bp in length with an A + T content of 68.9%. In the phylogenetic analyses,C. argenteoalbawas nested within Araneidae and the species from the superfamily Araneoidea form a momophyletic group. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of an orb-weaving spiderAraneus ventricosuswas determined. It is a circular molecule of 14,617 bp in length and contains a standard set of 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs and a control region. The A + T content of the overall base composition of majority strand (J-strand) is 73.4% (T: 38.5%; C: 10.1%; A: 34.9%; G: 16.5%). Among protein-coding genes, one gene (COI) begins with TTA, two (ATP6andND4) start with ATA, three (COII, COIIIandND6) begin with ATT and other seven genes use ATT as initiation codon.COIIIandND3end with an incomplete stop codon (T), andND1, ND2andCytbare terminated with TAG, while all other genes end with TAA as stop codon. Two regions including tandem repeats were found in the control region (D-loop): a 106 bp sequence tandemly repeated twice and a 195 bp sequence tandemly repeated twice with a partial third (120 bp). [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of a wolf spiderPirata subpiraticuswas determined. It is a circular molecule of 14,528 bp in length and contains 13 protein-coding genes, 2 ribosomal RNAs, 21 transfer RNAs (tRNAGlyis lost) and a control region. The A + T content of the overall base composition of majority strand (J-strand) is 75.6% (T: 42.0%; C: 8.6%; A:33.6%; G: 15.8%). Among protein-coding genes, one genes (COIII) start with TTG, four genes (ND1, ND2, ATP8andCytb) begin with ATT and other eight genes use ATA as initiation codon.ND2andCytbare terminated with TAG as stop codon, while all other genes end with TAA. Three isolated sequences repeat regions (212 bp) were found in the A+T-rich region (D-loop). [ABSTRACT FROM PUBLISHER]