Biological identification of springtails (Hexapoda: Collembola) from the Canadian Arctic, using mitochondrial DNA barcodes

We evaluated sequence diversity in the mitochondrial cytochrome-c oxidase I (COI; EC 1.9.3.1) gene as a tool for resolving differences among species of Arctic springtails. The Collembola examined in this analysis were collected from Igloolik, Cornwallis, and Somerset islands and included representatives from all major families found in the Arctic. Members of 13 genera and 19 species were examined, including 4 species of the genus Folsomia and 3 species of the genus Hypogastrura. In all cases, species were successfully discriminated. Sequence divergences within species were generally less than 1%, whereas divergences between species were greater than 8% in all cases. Divergences among individuals of one species of Folsomia were much higher (up to 13%), but this likely represents the presence of an undescribed sibling species. We conclude that DNA barcoding is a powerful tool for identifying species of Collembola and should regularly be useful as a complement to traditional, morphological taxonomy

Testing use of mitochondrial COI sequences for the identification and phylogenetic analysis of New Zealand caddisflies (Trichoptera)

We tested the hypothesis that cytochrome c oxidase subunit 1 (COI) sequences would successfully discriminate recognised species of New Zealand caddisflies. We further examined whether phylogenetic analyses, based on the COI locus, could recover currently recognised superfamilies and suborders. COI sequences were obtained from 105 individuals representing 61 species and all 16 families of Trichoptera known from New Zealand. No sequence sharing was observed between members of different species, and congeneric species showed from 2.3 to 19.5% divergence. Sequence divergence among members of a species was typically low (mean = 0.7%; range 0.0–8.5%), but two species showed intraspecific divergences in excess of 2%. Phylogenetic reconstructions based on COI were largely congruent with previous conclusions based on morphology, although the sequence data did not support placement of the purse-cased caddisflies (Hydroptilidae) within the uncased caddisflies, and, in particular, the Rhyacophiloidea. We conclude that sequence variation in the COI gene locus is an effective tool for the identification of New Zealand caddisfly species, and can provide preliminary phylogenetic inferences. Further research is needed to ascertain the significance of the few instances of high intra-specific divergence and to determine if any instances of sequence sharing will be detected with larger sample sizes

High levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation

We examined levels of genetic variability within and among populations of three Antarctic springtail species (Arthropoda: Collembola) and tested the hypothesis that genetic divergences occur among glacially-isolated habitats. The study was conducted in southern Victoria Land, Ross Dependency, Antarctica, and samples were collected from locations in the vicinity of the Mackay Glacier. We analyzed mtDNA (cytochrome c oxidase subunit I; COI) sequence variability for 97 individuals representing three species (Gomphiocephalus hodgsoni, N = 67; Cryptopygus nivicolus, N = 20; and Antarcticinella monoculata, N = 8). Haplotype diversity and genetic divergences were calculated and used to indicate population variability and also to infer divergence times of isolated populations using molecular clock estimates. Two of the three species showed high levels of genetic divergence. Gomphiocephalus hodgsoni, a widespread and common species, showed 7.6% sequence divergence on opposite sides of the Mackay Glacier. The more range restricted C. nivicolus showed 4.0% divergence among populations. The third species, A. monoculata, was found in only one location. Molecular clock estimates based on sequence divergences suggest that populations separated within the last 4 Mya. We conclude that habitat fragmentation resulting from Pliocene (5 Mya) and Pleistocene (2 Mya to 10 Kya) glaciations has promoted and maintained high levels of diversity among isolated springtail populations on relatively small spatial scales. The region surrounding the Mackay Glacier is likely to have provided refugia for springtail populations during glacial maxima and remains an area of high genetic and species diversity for Collembola within the Ross Sea region

Resolving the taxonomic status of potential biocontrol agents belonging to the neglected genus lipolexis Förster (Hymenoptera, Braconidae, Aphidiinae) with descriptions of six new species

Lipolexis is a small genus in the subfamily Aphidiinae represented by one species in Europe (Lipolexis gracilis Förster) and by four in Asia (Lipolexis wuyiensis Chen, L. oregmae Gahan, L. myzakkaiae Pramanik and Raychaudhuri and L. pseudoscutellaris Pramanik and Raychaudhuri). Although L. oregmae is employed in biological control programs against pest aphids, the last morphological study on the genus was completed over 50 years ago. This study employs an integrative approach (morphology and molecular analysis (COI barcode region)), to examine Lipolexis specimens that were sampled worldwide, including specimens from BOLD database. These results establish that two currently recognized species of Lipolexis (L. gracilis, L. oregmae) are actually a species complex and also reveal phylogenetic relationships within the genus. Six new species are described and a global key for the identification of Lipolexis species is provided.info:eu-repo/semantics/publishedVersio

Biodiversity baselines : tracking insects in Kruger National Park with DNA barcodes

Reflecting their species richness and ecological diversification, insects play a central role in terrestrial ecosystems but difficulties in species-level assignments have restricted large-scale analysis of their community structure. Employing South Africa’s largest national park as a model system, we demonstrate that DNA barcoding can break this barrier. A year-long deployment of Malaise traps at 25 sites in Kruger National Park (KNP) generated 1000+ weekly collections containing about 800,000 specimens. Insect biomass averaged 1.05 g per trap-day but varied by up to 2-fold between months, being lower in the dry than wet season. Nearly 370,000 specimens were individually analyzed to reveal 19,730 Barcode Index Numbers (BINs; species proxy), a count equal to 43% of the known insect fauna of southern Africa. There was clear differentiation in insect richness and composition between KNP’s two ecoregions, but little among the vegetation types comprising them. The spatial gradient in annual rainfall explained more than half of the variation in compositional similarity among sites with less similarity among samples in the wet season, particularly among those in high rainfall areas. These results suggest that the factors organising insect communities in KNP are not fine-scale vegetation differences, but larger-scale processes associated with ecoregions and rainfall. Estimates of sample coverage indicate that the species not collected are rare, comprising only 4% of the individuals in the community. With a well-parameterized DNA barcode reference library in place, metabarcoding can be used to assess future shifts in the insect fauna of KNP rapidly and inexpensively.http://www.elsevier.com/locate/bioconpm2021Paraclinical Science

A molecular-based identification resource for the arthropods of Finland

Publisher Copyright: © 2021 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this study, we (1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), (2) publish this library, and (3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi) at https://laji.fi/en/theme/protax. Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society.Peer reviewe

Phylogeographic structure in three North American tent caterpillar species (Lepidoptera: Lasiocampidae): Malacosoma americana, M. californica, and M. disstria

While phylogeographic structure has been examined in many North American vertebrate species, insects have received much less attention despite their central ecological roles. The moth genus Malacosoma (Hübner, 1820), is an important group of forestry pests responsible for large-scale defoliation across much of the Nearctic and Palearctic. The present study uses sequence variation in the mitochondrial cytochrome c oxidase 1 (COI) gene to examine the population genetic structure of the three widespread Malacosoma species (M. americana, M. californica, and M. disstria). Populations of all three species showed highest diversity in the south, suggesting that modern populations derived from southern refugia with loss of variation as these lineages dispersed northwards. However, despite similar life histories and dispersal abilities, the extent of regional variation varied among the taxa. M. americana, a species restricted to eastern North America, showed much less genetic structure than the western M. californica or the widespread M. disstria. The regional differentiation in the latter reflects the likely derivation of modern lineages from several refugia, as well as taxonomic uncertainty in M. californica. In these respects, the three species of Malacosoma share phylogeographic patterns similar to those detected in vertebrates which are characterised by greater phylogeographic breaks in the western half of the continent and limited structure in the east