Over the last two decades, the use of DNA barcodes has transformed our ability to identify and assess life on our planet. Both strengths and weaknesses of the method have been exemplified through thousands of peer-reviewed scientific articles. Given the novel sequencing approaches, currently capable of generating millions of reads at low cost, we reflect on the questions: What will the future bring for DNA barcoding? Will identification of species using short, standardized fragments of DNA stand the test of time? We present reflected opinions of early career biodiversity researchers in the form of a SWOT analysis and discuss answers to these questions.

DNA barcoding in Ceratopogonidae has been restricted to interpreting the medically and veterinary important members of Culicoides Latreille. Here the technique is utilised, together with morphological study, to interpret all members of the family in a select area. Limited sampling from the county of Finnmark in northernmost Norway indicated the presence of 54 species, including 14 likely new to science, 16 new to Norway, and one new to Europe. No species were previously recorded from this county. Only 93 species were known for all of Norway before this survey, indicating how poorly studied the group is. We evaluate and discuss morphological characters commonly used in identification of biting midges and relate species diagnoses to released DNA barcode data from 223 specimens forming 58 barcode clusters in our dataset. DNA barcodes and morphology were congruent for all species, except in three morphological species where highly divergent barcode clusters indicate the possible presence of cryptic species.

Background: Dragonflies and damselflies (Odonata) are important components in biomonitoring due to their amphibiotic lifecycle and specific habitat requirements. They are charismatic and popular insects, but can be challenging to identify despite large size and often distinct coloration, especially the immature stages. DNA-based assessment tools rely on validated DNA barcode reference libraries evaluated in a supraregional context to minimize taxonomic incongruence and identification mismatches.Methods: This study reports on findings from the analysis of the most comprehensive DNA barcode dataset for Central European Odonata to date, with 103 out of 145 recorded European species included and publicly deposited in the Barcode of Life Data System (BOLD). The complete dataset includes 697 specimens (548 adults, 108 larvae) from 274 localities in 16 countries with a geographic emphasis on Central Europe. We used BOLD to generate sequence divergence metrics and to examine the taxonomic composition of the DNA barcode clusters within the dataset and in comparison with all data on BOLD.Results: Over 88% of the species included can be readily identified using their DNA barcodes and the reference dataset provided. Considering the complete European dataset, unambiguous identification is hampered in 12 species due to weak mitochondrial differentiation and partial haplotype sharing. However, considering the known species distributions only two groups of five species possibly co-occur, leading to an unambiguous identification of more than 95% of the analysed Odonata via DNA barcoding in real applications. The cases of small interspecific genetic distances and the observed deep intraspecific variation inCordulia aenea(Linnaeus, 1758) are discussed in detail and the corresponding taxa in the public reference database are highlighted. They should be considered in future applications of DNA barcoding and metabarcoding and represent interesting evolutionary biological questions, which call for in depth analyses of the involved taxa throughout their distribution ranges.

: Global biodiversity gradients are generally expected to reflect greater species replacement closer to the equator. However, empirical validation of global biodiversity gradients largely relies on vertebrates, plants, and other less diverse taxa. Here we assess the temporal and spatial dynamics of global arthropod biodiversity dynamics using a beta-diversity framework. Sampling includes 129 sampling sites whereby malaise traps are deployed to monitor temporal changes in arthropod communities. Overall, we encountered more than 150,000 unique barcode index numbers (BINs) (i.e. species proxies). We assess between site differences in community diversity using beta-diversity and the partitioned components of species replacement and richness difference. Global total beta-diversity (dissimilarity) increases with decreasing latitude, greater spatial distance and greater temporal distance. Species replacement and richness difference patterns vary across biogeographic regions. Our findings support long-standing, general expectations of global biodiversity patterns. However, we also show that the underlying processes driving patterns may be regionally linked.

Non-biting midges of the fly family Chironomidae are extremely abundant and diverse in Arctic regions and are essential components of Arctic ecosystems. Modern identification tools based on documented records of Arctic chironomid species are therefore important for ecological research and environmental monitoring in the region. Here, we provide an updated review of the chironomid fauna of the Svalbard archipelago and the island of Jan Mayen, Norway. Our results show that a total of 73 species distributed across 24 genera in four subfamilies are known from these areas. Our review treats 109 taxa, including nomina dubia and misidentifications. It includes morphological identification keys to all known species as well as photographs of most taxa and DNA barcodes of 66 species. Taxonomic remarks are given for selected taxa, including previous misidentifications and erroneous records. Chironomus islandicus, Tvetenia bavarica, Limnophyes schnelli, Metriocnemus brusti and Metriocnemus fuscipes as well as the genera Allocladius, Corynoneura and Bryophaenocladius are reported from Svalbard for the first time, while Procladius (Holotanypus) frigidus, Stictochironomus psilopterus, Chaetocladius incertus, Orthocladius (Orthocladius) mixtus and Smittia longicosta, previously considered as junior synonyms or nomina dubia, are revived as valid species based on examination of type material or literature. Twenty species within eleven genera are introduced with interim names. Metriocnemus similis is regarded as a junior synonym of Metriocnemus ursinus, and Smittia incerta, Smittia flexinervis and Smittia spitzbergensis are regarded as nomina dubia. Valid taxa no longer considered as part of the Svalbard fauna are Parochlus kiefferi, Arctopelopia barbitarsis, Procladius (Holotanypus) crassinervis, Diamesa lindrothi, Diamesa incallida, Diamesa lundstromi, Chironomus hyperboreus, Sergentia coracina, Camptocladius stercorarius, Chaetocladius dissipatus, Chaetocladius dentiforceps, Chaetocladius laminatus, Chaetocladius perennis, Cricotopus (Cricotopus) humeralis, Cricotopus (Cricotopus) polaris, Hydrosmittia ruttneri, Limnophyes edwardsi, Metriocnemus picipes, Metriocnemus tristellus, Orthocladius (Eudactylocladius) gelidus, Orthocladius (Euorthocladius) thienemanni, Orthocladius (Orthocladius) obumbratus, Orthocladius (Orthocladius) rhyacobius, Paralimnophyes, Paraphaenocladius impensus, Psectrocladius (Monopsectrocladius) calcaratus, Psectrocladius (Psectrocladius) psilopterus, Psectrocladius (Psectrocladius) ventricosus, Smittia lasiophthalma, Smittia lasiops and Zalutschia tatrica.

The invertebrate fauna of anthropogenic soils in the High-Arctic settlement of Barentsburg, Svalbard