A re-analysis of the data in Sharkey et al.'s (2021) minimalist revision reveals that BINs do not deserve names, but BOLD Systems needs a stronger commitment to open science

Towards holistic insect monitoring: species discovery, description, identification and traits for all insects

Holistic insect monitoring needs scalable techniques to overcome taxon biases, determine species abundances, and gather functional traits for all species. This requires that we address taxonomic impediments and the paucity of data on abundance, biomass and functional traits. We here outline how these data deficiencies could be addressed at scale. The workflow starts with large-scale barcoding (megabarcoding) of all specimens from mass samples obtained at biomonitoring sites. The barcodes are then used to group the specimens into molecular operational taxonomic units that are subsequently tested/validated as species with a second data source (e.g. morphology). New species are described using barcodes, images and short diagnoses, and abundance data are collected for both new and described species. The specimen images used for species discovery then become the raw material for training artificial intelligence identification algorithms and collecting trait data such as body size, biomass and feeding modes. Additional trait data can be obtained from vouchers by using genomic tools developed by molecular ecologists. Applying this pipeline to a few samples per site will lead to greatly improved insect monitoring regardless of whether the species composition of a sample is determined with images, metabarcoding or megabarcoding. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.

Characterising the north-western European species of Phaenoglyphis Förster, 1869 (Hymenoptera: Figitidae: Charipinae) with novel insights from DNA barcode data

Background

The taxonomy of the hymenopteran parasitoid subfamily Charipinae (Hymenoptera: Cynipoidea: Figitidae) has, until recently, been in a state of chaos. While this situation has improved significantly in recent years, most of the efforts were focused on morphological data of typically old specimens. Here, we present the first integrative approach to describe the diversity of the genus Phaenoglyphis Förster, 1869 from north-western Europe.

New information

For seven (of a total of 17) species, we provide DNA barcode data. Phaenoglyphisbelizini Pujade-Villar, 2018 and Phaenoglyphisevenhuisi Pujade-Villar & Paretas-Martínez, 2006 are recorded for the first time from Germany. All DNA barcodes and specimen data were added to the publicly available GBOL and BOLD reference database. The presence of a 6 bp long deletion in the CO1 barcode region that is characteristic to the genus and unique amongst Figitidae supports the monophyly of Phaenoglyphis.

Cryptic diversity begets challenges and opportunities in biodiversity research

How many species of life are there on Earth? This is a question that we want to know but cannot yet answer. Some scholars speculate that the number of species may reach 2.2 billion when considering cryptic diversity and that each morphology-based insect species may contain an average of 3.1 cryptic species. With nearly two million described species, such high estimates of cryptic diversity would suggest that cryptic species are widespread. The development of molecular species delimitation has led to the discovery of a large number of cryptic species, and cryptic biodiversity has gradually entered our field of vision and attracted more attention. This paper introduces the concept of cryptic species, how they evolve, and methods by which they may be discovered and confirmed, and provides theoretical and methodological guidance for the study of hidden species. A workflow of how to confirm cryptic species is provided. In addition, the importance and reliability of multi-evidence-based integrated taxonomy are reaffirmed as a way to better standardize decision-making processes. Special focus on cryptic diversity and increased funding for taxonomy is needed to ensure that cryptic species in hyperdiverse groups are discoverable and described. An increased focus on cryptic species in the future will naturally arise as more difficult groups are studied, and thereby, we may finally better understand the rules governing the evolution and maintenance of cryptic biodiversity.

Towards a Canary Islands barcode database for soil biodiversity: revealing cryptic and unrecorded mite species diversity within insular soils

Soil arthropod diversity contributes to a high proportion of the total biodiversity on Earth. However, most soil arthropods are still undescribed, hindering our understanding of soil functioning and global biodiversity estimations. Inventorying soil arthropods using conventional taxonomical approaches is particularly difficult and costly due to the great species richness, abundance and local-scale heterogeneity of mesofauna communities and the poor taxonomic background knowledge of most lineages. To alleviate this situation, we have designed and implemented a molecular barcoding framework adapted to soil fauna. This pipeline includes different steps, starting with a morphology-based selection of specimens which are imaged. Then, DNA is extracted non-destructively. Both images and voucher specimens are used to assign a taxonomic identification, based on morphology that is further checked for consistency with molecular information. Using this procedure, we studied 239 specimens of mites from the Canary Islands including representatives of Mesostigmata, Sarcoptiformes and Trombidiformes, of which we recovered barcode sequences for 168 specimens that were morphologically identified to 49 species, with nine specimens that could only be identified at the genus or family levels. Multiple species delimitation analyses were run to compare molecular delimitations with morphological identifications, including ASAP, mlPTP, BINs and 3% and 8% genetic distance thresholds. Additionally, a species-level search was carried out at the Biodiversity Databank of the Canary Islands (BIOTA) to evaluate the number of species in our dataset that were not previously recorded in the archipelago. In parallel, a sequence-level search of our sequences was performed against BOLD Systems. Our results reveal that multiple morphologically identified species correspond to different molecular lineages, which points to significant levels of unknown cryptic diversity within the archipelago. In addition, we evidenced that multiple species in our dataset constituted new records for the Canary Islands fauna and that the information for these lineages within online genetic repositories is very incomplete. Our study represents the first systematic effort to catalogue the soil arthropod mesofauna of the Canary Islands and establishes the basis for the Canary Islands Soil Biodiversity barcode database. This resource will constitute a step forward in the knowledge of these arthropods in a region of special interest.

DNA Barcodes in Taxonomic Descriptions

This chapter discusses methods for incorporating DNA barcode information into formal taxonomic descriptions. We first review what a formal description entails and then discuss previous attempts to incorporate barcode information into taxonomic descriptions. Several computer programs are listed that extract diagnostics from DNA barcode data. Finally, we examine a test case (Astraptes taxonomy).

Species Diagnosis and DNA Taxonomy

The use of DNA has helped to improve and speed up species identification and delimitation. However, it also provides new challenges to taxonomists. Incongruence of outcome from various markers and delimitation methods, bias from sampling and skewed species distribution, implemented models, and the choice of methods/priors may mislead results and also may, in conclusion, increase elements of subjectivity in species taxonomy. The lack of direct diagnostic outcome from most contemporary molecular delimitation approaches and the need for a reference to existing and best sampled trait reference systems reveal the need for refining the criteria of species diagnosis and diagnosability in the current framework of nomenclature codes and good practices to avoid nomenclatorial instability, parallel taxonomies, and consequently more and new taxonomic impediment.

Principles for Constructing DNA Barcode Reference Libraries

All DNA barcode methods rely on reference sequences linked to well-curated voucher specimens. Definitions for and locations of DNA barcode reference libraries are not standardized, and vary throughout the literature. Standardizing, and centralizing reference specimens would provide an unambiguous source, analogous to reference genomes, to reproduce identifications and improve a library. This chapter proposes a working definition of a DNA barcode reference library, consistent with DNA barcode data standards, along with principles and methods to consider when producing or using such a library. These methods allow explicit traceback to sequence-sources which elevate the value of voucher specimens, and create a potential for community curation.

Assessment of the DNA barcode libraries for the study of the poorly-known rove beetle (Staphylinidae) fauna of West Siberia

Staphylinidae, or rove beetles, are one of the mega-diverse and abundant families of the ground-living terrestrial arthropods that is taxonomically poorly known even in the regions adjacent to Europe where the fauna has been investigated for the longest time. Since DNA barcoding is a tool to accelerate biodiversity research, here we explored if the currently-available COI barcode libraries are representative enough for the study of rove beetles of West Siberia. This is a vast region adjacent to Europe with poorly-known fauna of rove beetles and from where not a single DNA barcode has hitherto been produced for Staphylinidae. First, we investigated the faunal similarity between the rove beetle faunas of the climatically compatible West Siberia in Asia, Fennoscandia in Europe and Canada and Alaska in North America. Second, we investigated barcodes available for Staphylinidae from the latter two regions in BOLD and GenBank, the world's largest DNA barcode libraries. We conclude that the rather different rove beetle faunas of Fennoscandia, on the one hand and Canada and Alaska on the other hand, are well covered in both barcode libraries that complement each other. We also find that even without any barcodes originating from specimens collected in West Siberia, this coverage is helpful for the study of rove beetles there due to the significant number of widespread species shared between West Siberia and Fennoscandia and due to the even larger number of shared genera amongst all three investigated regions. For the first time, we compiled a literature-based checklist for 726 species of the West Siberian Staphylinidae supplemented by their occurrence dataset submitted to GBIF. Our script written for mining unique (i.e. not redundant) barcodes for a given geographic area across global libraries is made available here and can be adopted for any other regions.

Larval polyphagy of Cataspilatesmarceloi (Lepidoptera, Geometridae), a Neotropical geometrid moth with flightless females

Surveys in the arid shrubland of the central Andes revealed larval polyphagy for Cataspilatesmarceloi Vargas, 2022 (Lepidoptera, Geometridae, Ennominae, Boarmiini), a geometrid moth with flightless females. This discovery suggests that, as well as in the Holarctic fauna, larval polyphagy would have been important for the evolution of flightlessness among Neotropical geometrid moths of the tribe Boarmiini.

Collective and harmonized high throughput barcoding of insular arthropod biodiversity: Toward a Genomic Observatories Network for islands

Current understanding of ecological and evolutionary processes underlying island biodiversity is heavily shaped by empirical data from plants and birds, although arthropods comprise the overwhelming majority of known animal species, and as such can provide key insights into processes governing biodiversity. Novel high throughput sequencing (HTS) approaches are now emerging as powerful tools to overcome limitations in the availability of arthropod biodiversity data, and hence provide insights into these processes. Here, we explored how these tools might be most effectively exploited for comprehensive and comparable inventory and monitoring of insular arthropod biodiversity. We first reviewed the strengths, limitations and potential synergies among existing approaches of high throughput barcode sequencing. We considered how this could be complemented with deep learning approaches applied to image analysis to study arthropod biodiversity. We then explored how these approaches could be implemented within the framework of an island Genomic Observatories Network (iGON) for the advancement of fundamental and applied understanding of island biodiversity. To this end, we identified seven island biology themes at the interface of ecology, evolution and conservation biology, within which collective and harmonized efforts in HTS arthropod inventory could yield significant advances in island biodiversity research.

Metabarcoding and applied ecology with hyperdiverse organisms: Recommendations for biological control research

Metabarcoding is revolutionizing fundamental research in ecology by enabling large-scale detection of species and producing data that are rich with community context. However, the benefits of metabarcoding have yet to be fully realized in fields of applied ecology, especially those such as classical biological control (CBC) research that involve hyperdiverse taxa. Here, we discuss some of the opportunities that metabarcoding provides CBC and solutions to the main methodological challenges that have limited the integration of metabarcoding in existing CBC workflows. We focus on insect parasitoids, which are popular and effective biological control agents (BCAs) of invasive species and agricultural pests. Accurately identifying native, invasive and BCA species is paramount, since misidentification can undermine control efforts and lead to large negative socio-economic impacts. Unfortunately, most existing publicly accessible genetic databases cannot be used to reliably identify parasitoid species, thereby limiting the accuracy of metabarcoding in CBC research. To address this issue, we argue for the establishment of authoritative genetic databases that link metabarcoding data to taxonomically identified specimens. We further suggest using multiple genetic markers to reduce primer bias and increase taxonomic resolution. We also provide suggestions for biological control-specific metabarcoding workflows intended to track the long-term effectiveness of introduced BCAs. Finally, we use the example of an invasive pest, Drosophila suzukii, in a reflective "what if" thought experiment to explore the potential power of community metabarcoding in CBC.

Balclutha jafara (Hemiptera: Cicadellidae): integrative identification of a species introduced in the Western Hemisphere, and notes on other Balclutha

Leafhopper specimens of the genus Balclutha Kirkaldy, found in southern Florida (Palm Beach and Collier Counties), United States, beginning in 2020, and in shipments of plant products originating from Colombia and entering the United States beginning in 2019, are identified as B. jafara Webb. This species was previously known only from the Seychelles and Aldabra Islands, which are parts of the Seychelles archipelago in the Indian Ocean east of mainland Africa. Identifications were made by comparison with type specimens, both morphologically and through molecular analysis. Specimens in Palm Beach Co. were swept from commercial rice (Oryza sativa L.) paddies. Mitochondrial cytochrome c oxidase I (COI) barcodes of specimens from Florida and Colombia were closely matched to each other and to partial barcodes obtained from paratype specimens of B. jafara. The COI barcodes also closely matched sequences from previously unidentified Balclutha specimens in the Barcode of Life Data Systems (BOLD) from Kenya and South Africa, several of which were confirmed later morphologically as B. jafara. Previously unidentified museum specimens from South Sudan, Zambia, and Zimbabwe were determined as B. jafara. Together, these specimens show that B. jafara has a more widespread African distribution than was known previously, and that it arrived in the Western Hemisphere by 2019. Balclutha jafara is redescribed and illustrated. Further studies on the Balclutha fauna of Florida were performed. COI barcode data were generated for Floridian specimens of B. caldwelli Blocker, B. curvata Caldwell, B. flavescens (Baker), B. frontalis (Ferrari), B. incisa (Matsumura), and B. lucida (Butler). A phylogenetic analysis of COI data was conducted using publicly available sequences and those generated here. A key to the Balclutha species known from Florida is provided. The names that have been applied and mis-applied to Western Hemisphere species are discussed. To clarify the identity of some species, illustrations are given for: the female holotype and a male paratype of Eugnathodus virescens Osborn (=B. flavescens); the holotype of Nesosteles robustus Caldwell (=B. robusta); and the holotype of Balclutha curvata Caldwell. Additional barcoded specimens of Balclutha from Kenya and Pakistan were provided for examination by the BOLD research group and determined as B. sujawalensis Ahmed, previously known only from India and Pakistan, and this species is also illustrated here.

New species based on the biological species concept within the complex of Lariophagus distinguendus (Hymenoptera, Chalcidoidea, Pteromalidae), a parasitoid of household pests

The pteromalid parasitoid Lariophagus distinguendus (Foerster) belongs to the Hymenoptera, a megadiverse insect order with high cryptic diversity. It attacks stored product pest beetles in human storage facilities. Recently, it has been shown to consist of two separate species. To further study its cryptic diversity, strains were collected to compare their relatedness using barcoding and nuclear genes. Nuclear genes identified two clusters which agree with the known two species, whereas the barcode fragment determined an additional third Clade. Total reproductive isolation (RI) according to the biological species concept (BSC) was investigated in crossing experiments within and between clusters using representative strains. Sexual isolation exists between all studied pairs, increasing from slight to strong with genetic distance. Postzygotic barriers mostly affected hybrid males, pointing to Haldane's rule. Hybrid females were only affected by unidirectional Spiroplasma-induced cytoplasmic incompatibility and behavioural sterility, each in one specific strain combination. RI was virtually absent between strains separated by up to 2.8% COI difference, but strong or complete in three pairs from one Clade each, separated by at least 7.2%. Apparently, each of these clusters represents one separate species according to the BSC, highlighting cryptic diversity in direct vicinity to humans. In addition, these results challenge the recent 'turbo-taxonomy' practice of using 2% COI differences to delimitate species, especially within parasitic Hymenoptera. The gradual increase in number and strength of reproductive barriers between strains with increasing genetic distance also sheds light on the emergence of barriers during the speciation process in L. distinguendus.

Global determinants of insect mitochondrial genetic diversity

Understanding global patterns of genetic diversity is essential for describing, monitoring, and preserving life on Earth. To date, efforts to map macrogenetic patterns have been restricted to vertebrates, which comprise only a small fraction of Earth's biodiversity. Here, we construct a global map of predicted insect mitochondrial genetic diversity from cytochrome c oxidase subunit 1 sequences, derived from open data. We calculate the mitochondrial genetic diversity mean and genetic diversity evenness of insect assemblages across the globe, identify their environmental correlates, and make predictions of mitochondrial genetic diversity levels in unsampled areas based on environmental data. Using a large single-locus genetic dataset of over 2 million globally distributed and georeferenced mtDNA sequences, we find that mitochondrial genetic diversity evenness follows a quadratic latitudinal gradient peaking in the subtropics. Both mitochondrial genetic diversity mean and evenness positively correlate with seasonally hot temperatures, as well as climate stability since the last glacial maximum. Our models explain 27.9% and 24.0% of the observed variation in mitochondrial genetic diversity mean and evenness in insects, respectively, making an important step towards understanding global biodiversity patterns in the most diverse animal taxon.

Abundant, diverse, unknown: Extreme species richness and turnover despite drastic undersampling in two closely placed tropical Malaise traps

Arthropods account for a large proportion of animal biomass and diversity in terrestrial systems, making them crucial organisms in our environments. However, still too little is known about the highly abundant and megadiverse groups that often make up the bulk of collected samples, especially in the tropics. With molecular identification techniques ever more evolving, analysis of arthropod communities has accelerated. In our study, which was conducted within the Global Malaise trap Program (GMP) framework, we operated two closely placed Malaise traps in Padang, Sumatra, for three months. We analyzed the samples by DNA barcoding and sequenced a total of more than 70,000 insect specimens. For sequence clustering, we applied three different delimitation techniques, namely RESL, ASAP, and SpeciesIdentifier, which gave similar results. Despite our (very) limited sampling in time and space, our efforts recovered more than 10,000 BINs, of which the majority are associated with "dark taxa". Further analysis indicates a drastic undersampling of both sampling sites, meaning that the true arthropod diversity at our sampling sites is even higher. Regardless of the close proximity of both Malaise traps (< 360 m), we discovered significantly distinct communities.

A revision of the parasitoid wasp genus Alphomelon Mason with the description of 30 new species (Hymenoptera, Braconidae)

The parasitoid wasp genus Alphomelon Mason, 1981 is revised, based on a combination of basic morphology (dichotomous key and brief diagnostic descriptions), DNA barcoding, biology (host data and wasp cocoons), and distribution data. A total of 49 species is considered; the genus is almost entirely Neotropical (48 species recorded from that region), but three species reach the Nearctic, with one of them extending as far north as 45° N in Canada. Alphomelon parasitizes exclusively Hesperiinae caterpillars (Lepidoptera: Hesperiidae), mostly feeding on monocots in the families Arecaceae, Bromeliaceae, Cannaceae, Commelinaceae, Heliconiaceae, and Poaceae. Most wasp species parasitize either on one or very few (2-4) host species, usually within one or two hesperiine genera; but some species can parasitize several hosts from up to nine different hesperiine genera. Among species with available data for their cocoons, roughly half weave solitary cocoons (16) and half are gregarious (17); cocoons tend to be surrounded by a rather distinctive, coarse silk (especially in solitary species, but also distinguishable in some gregarious species). Neither morphology nor DNA barcoding alone was sufficient on its own to delimit all species properly; by integrating all available evidence (even if incomplete, as available data for every species is different) a foundation is provided for future studies incorporating more specimens, especially from South America. The following 30 new species are described: cruzi, itatiaiensis, and palomae, authored by Shimbori & Fernandez-Triana; and adrianguadamuzi, amazonas, andydeansi, calixtomoragai, carolinacanoae, christerhanssoni, diniamartinezae, duvalierbricenoi, eldaarayae, eliethcantillanoae, gloriasihezarae, guillermopereirai, hazelcambroneroae, josecortesi, keineraragoni, luciarosae, manuelriosi, mikesharkeyi, osvaldoespinozai, paramelanoscelis, paranigriceps, petronariosae, ricardocaleroi, rigoi, rostermoragai, sergioriosi, and yanayacu, authored by Fernandez-Triana & Shimbori.

Tightening the requirements for species diagnoses would help integrate DNA-based descriptions in taxonomic practice

Modern advances in DNA sequencing hold the promise of facilitating descriptions of new organisms at ever finer precision but have come with challenges as the major Codes of bionomenclature contain poorly defined requirements for species and subspecies diagnoses (henceforth, species diagnoses), which is particularly problematic for DNA-based taxonomy. We, the commissioners of the International Commission on Zoological Nomenclature, advocate a tightening of the definition of "species diagnosis" in future editions of Codes of bionomenclature, for example, through the introduction of requirements for specific information on the character states of differentiating traits in comparison with similar species. Such new provisions would enhance taxonomic standards and ensure that all diagnoses, including DNA-based ones, contain adequate taxonomic context. Our recommendations are intended to spur discussion among biologists, as broad community consensus is critical ahead of the implementation of new editions of the International Code of Zoological Nomenclature and other Codes of bionomenclature.

Morphological and DNA-based description of Trichophoromyia peixotoi n. sp. (Diptera: Psychodidae), a new sand fly species from the Brazilian Amazon

BACKGROUND

Phlebotomine sand flies of the genus Trichophoromyia Barretto, 1962 are of great relevance to public health as vectors of Leishmania protozoans. A new phlebotomine species named Trichophoromyia peixotoi n. sp. is here described based on both male morphology and COI DNA barcodes.

METHODS

The sand fly specimens were collected in the Parque Nacional da Amazônia (PNA), situated in the municipality of Itaituba, state of Pará, Brazil. Morphological description was done based on 10 male specimens. Five specimens were DNA barcoded for the COI gene.

RESULTS

The morphological and molecular analyses allowed the delimitation of this new species from others of Trichophoromyia. Trichophoromyia peixotoi n. sp. is closely related to other species with aedeagal ducts > 4 times the length of the sperm pump, from which it may be distinguished by the gonocoxite bristles and paramere shape.

CONCLUSIONS

The description of T. peixotoi n. sp. brings the number of species of Trichophoromyia to 45, including 24 for Brazil. The integrative taxonomy effort through the analysis of COI barcodes proved to be effective in the species delimitation of some Trichophoromyia spp.

Illustrated keys and a DNA barcode reference library of the amphibians and terrestrial reptiles (Amphibia, Reptilia) of São Tomé and Príncipe (Gulf of Guinea, West Africa)

The herpetofauna of São Tomé and Príncipe consists of nine species of amphibians, all endemic, and 21 species of terrestrial reptiles, of which 17 are endemic. Our current knowledge regarding its natural history, ecology, and distribution is limited. Here two important tools are provided to support researchers, conservationists, and local authorities in the identification of the country's herpetofauna: an illustrated key to the herpetofauna of the two islands and surroundings islets and a DNA barcode reference library. The keys allow a rapid and unambiguous morphological identification of all occurring species. The DNA barcodes for the entire herpetofauna of the country were produced from 79 specimens, all of which are deposited in museum collections. The barcodes generated are available in online repositories and can be used to provide unambiguous molecular identification of most of the species. Future applications and use of these tools are briefly discussed.

Taxonomy and Biological Control: New Challenges in an Old Relationship

Biological control and taxonomy are continuously developing fields with remarkable impacts on society. At least 80 years of literature have documented this relationship, which remains essentially the same in its mutualistic nature, as well as in its major challenges. From the perspective of Brazilian taxonomists, we discuss the impacts of important scientific and social developments that directly affect research in these areas, posing new challenges for this lasting relationship. The increasing restrictions and concerns regarding the international transit of organisms require improvements in research related to risk assessment for exotic biological control agents and also stimulate prospecting within the native biota. In our view, this is a positive situation that can foster a closer relationship between taxonomists and applied entomologists, as well as local surveys and taxonomic studies that are necessary before new programs and agents can be implemented. We discuss the essential role of molecular biology in this context, as an iconic example of the synergy between applied sciences and natural history. As our society comes to need safer and more sustainable solutions for food security and the biodiversity crisis, scientific progress will build upon this integration, where biological control and taxonomy play an essential role.

Facing the infinity: tackling large samples of challenging Chironomidae (Diptera) with an integrative approach

Background

Integrative taxonomy is becoming ever more significant in biodiversity research as scientists are tackling increasingly taxonomically challenging groups. Implementing a combined approach not only guarantees more accurate species identification, but also helps overcome limitations that each method presents when applied on its own. In this study, we present one application of integrative taxonomy for the highly abundant and particularly diverse fly taxon Chironomidae (Diptera). Although non-biting midges are key organisms in merolimnic systems, they are often cast aside in ecological surveys because they are very challenging to identify and extremely abundant.

Methods

Here, we demonstrate one way of applying integrative methods to tackle this highly diverse taxon. We present a three-level subsampling method to drastically reduce the workload of bulk sample processing, then apply morphological and molecular identification methods in parallel to evaluate species diversity and to examine inconsistencies across methods.

Results

Our results suggest that using our subsampling approach, identifying less than 10% of a sample's contents can reliably detect >90% of its diversity. However, despite reducing the processing workload drastically, the performance of our taxonomist was affected by mistakes, caused by large amounts of material. We conducted misidentifications for 9% of vouchers, which may not have been recovered had we not applied a second identification method. On the other hand, we were able to provide species information in cases where molecular methods could not, which was the case for 14% of vouchers. Therefore, we conclude that when wanting to implement non-biting midges into ecological frameworks, it is imperative to use an integrative approach.

Illuminating a Dark Taxon: Revision of European Trichacis Förster (Hymenoptera: Platygastridae) reveals a glut of synonyms

The parasitoid wasp genus Trichacis Förster is revised for Europe. Examination of historical and modern collections combined with DNA barcoding revealed the presence of only a single species in Europe, Trichacis tristis (Nees, 1834), redescribed here. Fourteen new synonymies are proposed for T. tristis: T. abdominalis Thomson, 1859 syn.nov.; T. bidentiscutum Szabó, 1981 syn.nov.; T. didas (Walker, 1835) syn.nov.; T. fusciala Szabó, 1981 syn.nov.; T. hajduica Szabó, 1981 syn.nov.; T. illusor Kieffer, 1916 syn.nov.; T. nosferatus Buhl, 1997 syn.nov.; T. pisis (Walker, 1835) syn.nov.; T. persicus Asadi & Buhl, 2021 syn.nov.; T. pulchricornis Szelényi, 1953 syn.nov.; T. quadriclava Szabó, 1981 syn.nov.; T. remulus (Walker, 1835) syn.nov.; T. vitreus Buhl, 1997 syn.nov.; T. weiperti Buhl, 2019 syn.nov.. Four species are transferred to Amblyaspis Förster: A. afurcata (Szabó, 1977) comb. nov., A. hungarica (Szabó, 1977), comb. nov., A. pannonica (Szabó, 1977) comb. nov., and A. tatika (Szabó, 1977) comb. nov. Intraspecific variation, biological associations, and taxonomic history are discussed. DNA barcodes are provided and analyzed in the context of worldwide Trichacis and its sister genus Isocybus Förster.

Single-specimen systematics resolves the phylogeny and diversity conundrum of enigmatic crustacean y-larvae

Resolving the evolutionary history of organisms is a major goal in biology. Yet for some taxa the diversity, phylogeny, and even adult stages remain unknown. The enigmatic crustacean "y-larvae" (Facetotecta) is one particularly striking example. Here we use extensive video-imaging and single-specimen molecular sequencing of >200 y-larval specimens to comprehensively explore for the first time their evolutionary history and diversity. This integrative approach revealed five major clades of Facetotecta, four of which encompass a considerable larval diversity. Whereas morphological analyses recognized 35 y-naupliar "morphospecies", molecular species delimitation analyses suggested the existence of between 88 and 127 species. The phenotypic and genetic diversity between the morphospecies suggests that a more elaborate classification than the current one-genus approach is needed. Morphology and molecular data were highly congruent at shallower phylogenetic levels, but no morphological synapomorphies could be unambiguously identified for major clades, which mostly comprise both planktotrophic and lecithotrophic y-nauplii. We argue that lecithotrophy arose several times independently whereas planktotrophic y-nauplii, which are structurally more similar across clades, most likely display the ancestral feeding mode of Facetotecta. We document a remarkably complex and highly diverse phylogenetic backbone for a taxon of marine crustaceans, the full life cycle of which remains a mystery.

Morphology, nuclear SNPs and mate selection reveal that COI barcoding overestimates species diversity in a Mediterranean freshwater amphipod by an order of magnitude

DNA sequence information has revealed many morphologically cryptic species worldwide. For animals, DNA-based assessments of species diversity usually rely on the mitochondrial cytochrome c oxidase subunit I (COI) gene. However, a growing amount of evidence indicate that mitochondrial markers alone can lead to misleading species diversity estimates due to mito-nuclear discordance. Therefore, reports of putative species based solely on mitochondrial DNA should be verified by other methods, especially in cases where COI sequences are identical for different morphospecies or where divergence within the same morphospecies is high. Freshwater amphipods are particularly interesting in this context because numerous putative cryptic species have been reported. Here, we investigated the species status of the numerous mitochondrial molecular operational taxonomic units (MOTUs) found within Echinogammarus sicilianus. We used an integrative approach combining DNA barcoding with mate selection observations, detailed morphometrics and genome-wide double digest restriction site-associated DNA sequencing (ddRAD-seq). Within a relatively small sampling area, we detected twelve COI MOTUs (divergence = 1.8-20.3%), co-occurring in syntopy at two-thirds of the investigated sites. We found that pair formation was random and there was extensive nuclear gene flow among the ten MOTUs co-occurring within the same river stretch. The four most common MOTUs were also indistinguishable with respect to functional morphology. Therefore, the evidence best fits the hypothesis of a single, yet genetically diverse, species within the main river system. The only two MOTUs sampled outside the focal area were genetically distinct at the nuclear level and may represent distinct species. Our study reveals that COI-based species delimitation can significantly overestimate species diversity, highlighting the importance of integrative taxonomy for species validation, especially in hyperdiverse complexes with syntopically occurring mitochondrial MOTUs.

Future of DNA-based insect monitoring

Insects are crucial for ecosystem health but climate change and pesticide use are driving massive insect decline. To mitigate this loss, we need new and effective monitoring techniques. Over the past decade there has been a shift to DNA-based techniques. We describe key emerging techniques for sample collection. We suggest that the selection of tools should be broadened, and that DNA-based insect monitoring data need to be integrated more rapidly into policymaking. We argue that there are four key areas for advancement, including the generation of more complete DNA barcode databases to interpret molecular data, standardisation of molecular methods, scaling up of monitoring efforts, and integrating molecular tools with other technologies that allow continuous, passive monitoring based on images and/or laser imaging, detection, and ranging (LIDAR).

The first DNA barcode library of Chironomidae from the Tibetan Plateau with an evaluation of the status of the public databases

The main aim of this study was to curate a COI barcode library of Chironomidae from the Tibetan Plateau (TP) as an essential supplement to the public database. Another aim is to evaluate the current status of the public database of Chironomidae in aspects of taxonomic coverage, geographic representation, barcode quality, and efficiency for molecular identification, the Tibetan Plateau, China. In this study, 512 individuals of Chironomidae from the TP were identified based on morphological taxonomy and barcode analysis. The metadata of public records of Chironomidae were downloaded from the BOLD, and the quality of the public barcodes was ranked using the BAGS program. The reliability of the public library for molecular identification was evaluated with the newly curated library using the BLAST method. The newly curated library comprised 159 barcode species of 54 genera, of which 58.4% of species were likely new to science. There were great gaps in the taxonomic coverage and geographic representation in the public database, and only 29.18% of barcodes were identified at the species level. The quality of the public database was of concern, with only 20% of species being determined as concordant between BINs and morphological species. The accuracy of molecular identification using the public database was poor, and about 50% of matched barcodes could be correctly identified at the species level at the identity threshold of 97%. Based on these data, some recommendations are included here for improving barcoding studies on Chironomidae. The species richness of Chironomidae from the TP is much higher than ever recorded. Barcodes from more taxonomic groups and geographic regions are urgently needed to fill the great gap in the current public database of Chironomidae. Users should take caution when public databases are adopted as reference libraries for the taxonomic assignment.

Eastern Colombian Páramo Liodessus Guignot, 1939 diving beetles are genetically structured, but show signs of hybridization, with description of new species and subspecies (Coleoptera, Dytiscidae)

We studied Liodessus diving beetles from six eastern Colombian Páramo areas, as well as from the Altiplano. We discovered a highly characteristic new species, based on male genital morphology, Liodessus santarositasp. nov., in the Páramo de Guantiva-Rusia. Specimens from the Altiplano around Bogotá, and the Páramos of Almorzadero, Chingaza, Matarredonda, Rabanal y Rio Bogotá and Sumapaz form one clade of genetically similar populations based on mitochondrial Cox1 sequence data. The individuals of this clade are sub-structured according to their geographic distribution. The populations differ from each other mainly in terms of body size and coloration and, at most, subtly in their genital morphology. In two cases, we find putative hybrid populations between Altiplano and Páramo areas. We suggest that the different Páramo populations are in an early phase of speciation, and perhaps already genetically isolated in some cases. They are here assigned subspecies status to highlight these ongoing processes pending more comprehensive geographic sampling and use of genomic data. We refer to this clade as the Liodessus bogotensis complex, containing Liodessus b. bogotensis Guignot, 1953; Liodessus b. almorzaderossp. nov.; Liodessus b. chingazassp. nov.; Liodessus b. lacunaviridis Balke et al., 2021, stat. nov.; Liodessus b. matarredondassp. nov., and Liodessus b. sumapazssp. nov.

Taxonomic identification accuracy from BOLD and GenBank databases using over a thousand insect DNA barcodes from Colombia

Recent declines of insect populations at high rates have resulted in the need to develop a quick method to determine their diversity and to process massive data for the identification of species of highly diverse groups. A short sequence of DNA from COI is widely used for insect identification by comparing it against sequences of known species. Repositories of sequences are available online with tools that facilitate matching of the sequences of interest to a known individual. However, the performance of these tools can differ. Here we aim to assess the accuracy in identification of insect taxonomic categories from two repositories, BOLD Systems and GenBank. This was done by comparing the sequence matches between the taxonomist identification and the suggested identification from the platforms. We used 1,160 COI sequences representing eight orders of insects from Colombia. After the comparison, we reanalyzed the results from a representative subset of the data from the subfamily Scarabaeinae (Coleoptera). Overall, BOLD systems outperformed GenBank, and the performance of both engines differed by orders and other taxonomic categories (species, genus and family). Higher rates of accurate identification were obtained at family and genus levels. The accuracy was higher in BOLD for the order Coleoptera at family level, for Coleoptera and Lepidoptera at genus and species level. Other orders performed similarly in both repositories. Moreover, the Scarabaeinae subset showed that species were correctly identified only when BOLD match percentage was above 93.4% and a total of 85% of the samples were correctly assigned to a taxonomic category. These results accentuate the great potential of the identification engines to place insects accurately into their respective taxonomic categories based on DNA barcodes and highlight the reliability of BOLD Systems for insect identification in the absence of a large reference database for a highly diverse country.

A survey of aquatic macroinvertebrates in a river from the dry corridor of Nicaragua using biological indices and DNA barcoding

Aquatic macroinvertebrates are widely used as indicators for water quality assessment around the world. Modern strategies for environmental assessment implement molecular analysis to delimitate species of aquatic macroinvertebrates. Delimitation methods have been established to determine boundaries between species units using sequencing data from DNA barcodes and serve as first exploratory tools for taxonomic revisions. This is useful in regions such as the neotropics where aquatic macroinvertebrate habitats are threatened by human interference and DNA databases remain understudied. We asked whether the biodiversity of aquatic macroinvertebrates in a stream in Nicaragua, within the Central American Dry Corridor, could be characterized with biological indices and DNA barcoding. In this study, we combined regional biological indices (BMWP-CR, IBF-SV-2010) along with distance-based (ASAP, BIN) and tree-based (GMYC, bPTP) delimitation methods, as well as nucleotide BLAST in public barcode databases. We collected samples from the upper, middle, and low reaches of the Petaquilla river. The three sites presented excellent water quality with the BMWP-CR index, but evidence of high organic pollution was found in the middle reach with the IBF-SV-2010 index. We report a total of 219 COI sequences successfully generated from 18 families and 8 orders. Operational taxonomic units (OTUs) designation ranged from 69 to 73 using the four methods, with a congruency of 92% for barcode assignation. Nucleotide BLAST identified 14 species (27.4% of barcodes) and 33 genera (39.3% of barcodes) from query sequences in GenBank and BOLD system databases. This small number of identified OTUs may be explained by the paucity of molecular data from the Neotropical region. Our study provides valuable information about the characterization of macroinvertebrate families that are important biological indicators for the assessment of water quality in Nicaragua. The application of molecular approaches will allow the study of local diversity and further improve the application of molecular techniques for biomonitoring.

DNA barcoding echinoderms from the East Coast of South Africa. The challenge to maintain DNA data connected with taxonomy

Echinoderms are marine water invertebrates that are represented by more than 7000 extant species, grouped in five classes and showing diverse morphologies (starfish, sea lilies, feather stars, sea urchins, sea cucumbers, brittle and basket stars). In an effort to further study their diversity, DNA barcodes (DNA fragments of the 5' end of the cytochrome c oxidase subunit I gene, COI) have been used to complement morphological examination in identifying evolutionary lineages. Although divergent clusters of COI sequences were reported to generally match morphological species delineations, they also revealed some discrepancies, suggesting overlooked species, ecophenotypic variation or multiple COI lineages within one species. Here, we sequenced COI fragments of 312 shallow-water echinoderms of the East Coast of South Africa (KwaZulu-Natal Province) and compared morphological identifications with species delimitations obtained with four methods that are exclusively based on COI sequences. We identified a total of 103 morphospecies including 18 that did not exactly match described species. We also report 46 COI sequences that showed large divergences (>5% p-distances) with those available to date and publish the first COI sequences for 30 species. Our analyses also identified discordances between morphological identifications and COI-based species delimitations for a considerable proportion of the morphospecies studied here (49/103). For most of them, further investigation is necessary to keep a sound connection between taxonomy and the growing importance of DNA-based research.

Chromosomes as Barcodes: Discovery of a New Species of Black Fly (Diptera: Simuliidae) from California, USA

One of the most popular tools for species discovery and resolution is the DNA barcode, typically based on the cytochrome c oxidase I (COI) gene. However, other non-genic barcodes are available for Diptera. The banding sequence of polytene chromosomes in some dipteran cells, particularly of the larval silk glands, can provide a unique species barcode. We used the sequence of bands to reveal a new species of black fly in the Simulium (Boreosimulium) annulus species group from California, USA. To further characterize the species and provide more integrated taxonomy, we morphologically described all life stages above the egg, formally named the species Simulium ustulatum n. sp., and provided a conventional COI barcode. The COI barcode confirmed the chromosomal and morphological evidence that the species is a new member of the S. annulus group, and enabled identification of the larva and female, which are structurally similar to those of other species. The chromosomal barcode shows that this species has the most rearranged complement, compared with the eight other North American members of its species group, with up to 12 times the number of fixed rearrangements. Up to six chromosomal rearrangements, including autosomal polymorphisms and sex-linked phenomena, are shared with other members of the group. The most unique and conspicuous chromosomal feature of this new species is a large, pale-staining chromocenter from which the six chromosomal arms radiate. The distribution of this univoltine species in lowland rivers of California's Central Valley could make it vulnerable, given climate change and increasing land development.

Karyotype and COI gene sequences of Chironomusmelanotus Keyl, 1961 from the Yaroslavl region, Russia, and the difficulties with its identification using GenBank and BOLD systems

Karyotype and COI gene sequences of Chironomusmelanotus Keyl, 1961 from the Yaroslavl region (Russia) were analyzed. A low level of chromosomal polymorphism has been confirmed, eventually eight banding sequences were found: melA1, melB1, melC1, melD1, melE1, melF1, and melG1; only melD2 was found in two larvae from the Sunoga river. Analysis of phylogenetic tree and estimated genetic distances has shown not all COI gene sequences of Ch.melanotus in GenBank and BOLD to belong to this species. The lower distance of 0.4% was observed between two sequences from the Yaroslavl region and Finland, apparently these are true Ch.melanotus sequences. The distances between true Ch.melanotus and other sequences from Finland were 9.5% and 12.4%, and from Sweden it was 11%. The average genetic distance between studied sequences of 9.1% is out of the range of the 3% threshold previously determined for chironomids. According to our estimates, there are two sequences with a distance of 2.9% that may belong to Ch.annularius Meigen, 1818, and one sequence with a genetic distance of 2.1%, may belonging to Ch.cingulatus Meigen, 1830, which has been confirmed karyologically. Another two sequences form a separate cluster. We suggest that they either belong to a known species, but are not present in the databases, or belong to a distinct, undescribed species.

More discussion of minimalist species descriptions and clarifying some misconceptions contained in Meier et al. 2021

This is a response to a preprint version of "A re-analysis of the data in Sharkey et al.'s (2021) minimalist revision reveals that BINs do not deserve names, but BOLD Systems needs a stronger commitment to open science", https://www.biorxiv.org/content/10.1101/2021.04.28.441626v2. Meier et al. strongly criticized Sharkey et al.'s publication in which 403 new species were deliberately minimally described, based primarily on COI barcode sequence data. Here we respond to these criticisms. The following points are made: 1) Sharkey et al. did not equate BINs with species, as demonstrated in several examples in which multiple species were found to be in single BINs. 2) We reiterate that BINs were used as a preliminary sorting tool, just as preliminary morphological identification commonly sorts specimens based on color and size into unit trays; despite BINs and species concepts matching well over 90% of species, this matching does not equate to equality. 3) Consensus barcodes were used only to provide a diagnosis to conform to the rules of the International Code of Zoological Nomenclature just as consensus morphological diagnoses are. The barcode of a holotype is definitive and simply part of its cellular morphology. 4) Minimalist revisions will facilitate and accelerate future taxonomic research, not hinder it. 5) We refute the claim that the BOLD sequences of Plesiocoelusvanachterbergi are pseudogenes and demonstrate that they simply represent a frameshift mutation. 6) We reassert our observation that morphological evidence alone is insufficient to recognize species within species-rich higher taxa and that its usefulness lies in character states that are congruent with molecular data. 7) We show that in the cases in which COI barcodes code for the same amino acids in different putative species, data from morphology, host specificity, and other ecological traits reaffirm their utility as indicators of genetically distinct lineages.

New Arthrobotrys Nematode-Trapping Species (Orbiliaceae) from Terrestrial Soils and Freshwater Sediments in China

Arthrobotrys is the most complex genus of Orbiliaceae nematode-trapping fungi. Its members are widely distributed in various habitats worldwide due to their unique nematode-trapping survival strategies. During a survey of nematophagous fungi in Yunnan Province, China, twelve taxa were isolated from terrestrial soil and freshwater sediment habitats and were identified as six new species in Arthrobotrys based on evidence from morphological and multigene (ITS, TEF, and RPB2) phylogenetic analyses. These new species i.e., Arthrobotrys eryuanensis, A. jinpingensis, A. lanpingensis, A. luquanensis, A. shuifuensis, and A. zhaoyangensis are named in recognition of their places of origin. Morphological descriptions, illustrations, taxonomic notes, and a multilocus phylogenetic analysis are provided for all new taxa. In addition, a key to known species in Arthrobotrys is provided, and the inadequacies in the taxonomic study of nematode-trapping fungi are also discussed.

Multiple species delimitation approaches with COI barcodes poorly fit each other and morphospecies – An integrative taxonomy case of Sri Lankan Sericini chafers (Coleoptera: Scarabaeidae)

DNA taxonomy including barcoding and metabarcoding is widely used to explore the diversity in biodiversity hotspots. In most of these hotspot areas, chafers are represented by a multitude of species, which are well defined by the complex shape of male genitalia. Here, we explore how well COI barcode data reflect morphological species entities and thus their usability for accelerated species inventorization. We conducted dedicated field surveys in Sri Lanka to collect the species‐rich and highly endemic Sericini chafers (Coleoptera: Scarabaeidae). Congruence among results of a series of protocols for de novo species delimitation and with morphology‐based species identifications was investigated. Different delimitation methods, such as the Poisson tree processes (PTP) model, Statistical Parsimony Analysis (TCS), Automatic Barcode Gap Discovery (ABGD), Assemble Species by Automatic Partitioning (ASAP), and Barcode Index Number (BIN) assignments, resulted in different numbers of molecular operational taxonomic units (MOTUs). All methods showed both over‐splitting and lumping of morphologically identified species. Only 18 of the observed 45 morphospecies perfectly matched MOTUs from all methods. The congruence of delimitation between MOTUs and morphospecies expressed by the match ratio was low, ranging from 0.57 to 0.67. TCS and multirate PTP (mPTP) showed the highest match ratio, while (BIN) assignment resulted in the lowest match ratio and most splitting events. mPTP lumped more species than any other method. Principal coordinate analysis (PCoA) on a match ratio‐based distance matrix revealed incongruent outcomes of multiple DNA delimitation methods, although applied to the same data. Our results confirm that COI barcode data alone are unlikely to correctly delimit all species, in particular, when using only a single delimitation approach. We encourage the integration of various approaches and data, particularly morphology, to validate species boundaries.

Towards Large-scale Integrative Taxonomy (LIT): resolving the data conundrum for dark taxa

New, rapid, accurate, scalable, and cost-effective species discovery and delimitation methods are needed for tackling “dark taxa,” here defined as groups for which \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$<$\end{document}10\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} of all species are described and the estimated diversity exceeds 1,000 species. Species delimitation for these taxa should be based on multiple data sources (“integrative taxonomy”) but collecting multiple types of data risks impeding a discovery process that is already too slow. We here develop large-scale integrative taxonomy (LIT), an explicit method where preliminary species hypotheses are generated based on inexpensive data that can be obtained quickly and cost-effectively. These hypotheses are then evaluated based on a more expensive type of “validation data” that is only obtained for specimens selected based on objective criteria applied to the preliminary species hypotheses. We here use this approach to sort 18,000 scuttle flies (Diptera: Phoridae) into 315 preliminary species hypotheses based on next-generation sequencing barcode (313 bp) clusters (using objective clustering [OC] with a 3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} threshold). These clusters are then evaluated with morphology as the validation data. We develop quantitative indicators for predicting which barcode clusters are likely to be incongruent with morphospecies by randomly selecting 100 clusters for in-depth validation with morphology. A linear model demonstrates that the best predictors for incongruence between barcode clusters and morphology are maximum p-distance within the cluster and a newly proposed index that measures cluster stability across different clustering thresholds. A test of these indicators using the 215 remaining clusters reveals that these predictors correctly identify all clusters that are incongruent with morphology. In our study, all morphospecies are true or disjoint subsets of the initial barcode clusters so that all incongruence can be eliminated by varying clustering thresholds. This leads to a discussion of when a third data source is needed to resolve incongruent grouping statements. The morphological validation step in our study involved 1,039 specimens (5.8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} of the total). The formal LIT protocol we propose would only have required the study of 915 (5.1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document}: 2.5 specimens per species), as we show that clusters without signatures of incongruence can be validated by only studying two specimens representing the most divergent haplotypes. To test the generality of our results across different barcode clustering techniques, we establish that the levels of incongruence are similar across OC, Automatic Barcode Gap Discovery (ABGD), Poisson Tree Processes (PTP), and Refined Single Linkage (RESL) (used by Barcode of Life Data System to assign Barcode Index Numbers [BINs]). OC and ABGD achieved a maximum congruence score with the morphology of 89\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} while PTP was slightly less effective (84\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document}). RESL could only be tested for a subset of the specimens because the algorithm is not public. BINs based on 277 of the original 1,714 haplotypes were 86\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} congruent with morphology while the values were 89\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} for OC, 74\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} for PTP, and 72\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\%$\end{document} for ABGD. [Biodiversity discovery; dark taxa; DNA barcodes; integrative taxonomy.]

DNA barcoding for biodiversity assessment: Croatian stoneflies (Insecta: Plecoptera)

Background

The hemi-metabolous aquatic order Plecoptera (stoneflies) constitutes an indispensable part of terrestrial and aquatic food webs due to their specific life cycle and habitat requirements. Stoneflies are considered one of the most sensitive groups to environmental changes in freshwater ecosystems and anthropogenic changes have caused range contraction of many species. Given the critical threat to stoneflies, the study of their distribution, morphological variability and genetic diversity should be one of the priorities in conservation biology. However, some aspects about stoneflies, especially a fully resolved phylogeny and their patterns of distribution are not well known. A study that includes comprehensive field research and combines morphological and molecular identification of stoneflies has not been conducted in Croatia so far. Thus, the major aim of this study was to regenerate a comprehensive and taxonomically well-curated DNA barcode database for Croatian stoneflies, to highlight the morphological variability obtained for several species and to elucidate results in light of recent taxonomy.

Methods

A morphological examination of adult specimens was made using basic characteristics for distinguishing species: terminalia in males and females, head and pronotum patterns, penial morphology, and egg structures. DNA barcoding was applied to many specimens to help circumscribe known species, identify cryptic or yet undescribed species, and to construct a preliminary phylogeny for Croatian stoneflies.

Results

Sequences (658 bp in length) of 74 morphospecies from all families present in Croatia were recovered from 87% of the analysed specimens (355 of 410), with one partial sequence of 605 bp in length for Capnopsis schilleri balcanica Zwick, 1984. A total of 84% morphological species could be unambiguously identified using COI sequences. Species delineation methods confirmed the existence of five deeply divergent genetic lineages, with monophyletic origin, which also differ morphologically from their congeners and represent distinct entities. BIN (Barcode Index Number) assignment and species delineation methods clustered COI sequences into different numbers of operational taxonomic units (OTUs). ASAP delimited 76 putative species and achieved a maximum match score with morphology (97%). ABGD resulted in 62 and mPTP in 61 OTUs, indicating a more conservative approach. Most BINs were congruent with traditionally recognized species. Deep intraspecific genetic divergences in some clades highlighted the need for taxonomic revision in several species-complexes and species-groups. Research has yielded the first molecular characterization of nine species, with most having restricted distributions and confirmed the existence of several species which had been declared extinct regionally.

Turbo taxonomy approaches: lessons from the past and recommendations for the future based on the experience with Braconidae (Hymenoptera) parasitoid wasps

Not aplicable to a Forum paper, but if needed I can write one.

Revision of Neotropical Scythrididae moths and descriptions of 22 new species from Argentina, Chile, and Peru (Lepidoptera, Gelechioidea)

The taxonomy of South American Scythrididae (Lepidoptera: Gelechioidea) is revised, based on external morphology, genitalia, male abdominal segment VIII, and DNA barcodes using genetic distances, BINs, and a tentative molecular phylogeny. Data include both historical and fresh specimens from Argentina, Brazil, Colombia, Chile, Ecuador, Paraguay, and Peru. Thirty-four species are recognised as valid, and the fauna classified in three genera. Type specimens and morphology of all species are described and figured in detail. DNA barcode sequences of the COI gene were successful for 22 species, the average genetic divergence between species being 5.1%. A key to Neotropical Scythrididae species is provided, based on the male genitalia and abdominal segment VIII, which show most and easily accessible interspecific differences.

Our study revealed that the Scythridae fauna of South America is more or less completely unknown. As a result, 22 new species are described, increasing the number of South American Scythrididae species from 13 to 34. All new species are authored by Kari Nupponen (incertae sedis means the genus combination is uncertain and needs further research, country of the type locality is given in parentheses): Rhamphurasubdimotasp. nov. (Argentina), R.pozohondaensissp. nov. (Argentina), R.spiniuncussp. nov. (Argentina), R.angulisociellasp. nov. incertae sedis (Argentina), R.curvisociellasp. nov. incertae sedis (Argentina), R.tetrafasciellasp. nov. incertae sedis (Argentina), Landryiaankylosauroidessp. nov. incertae sedis (Argentina), L.chilensissp. nov. incertae sedis (Chile), Scythrisdirectiphallellasp. nov. (Argentina), S.furciphallellasp. nov. (Argentina), S.manchaoensissp. nov. (Argentina), S.salinasgrandensissp. nov. (Argentina), S.angustivalvellasp. nov. (Argentina), S.caimancitoensissp. nov. (Argentina), S.lequetepequensissp. nov. (Peru), S.sanfriscoensissp. nov. (Argentina), S.tigrensissp. nov. (Argentina), S.bicoloristrigellasp. nov. incertae sedis (Argentina), S.saldaitisisp. nov. incertae sedis (Argentina), S.wikstromisp. nov. incertae sedis (Argentina), S.andensissp. nov. incertae sedis (Argentina), S.mendozaensissp. nov. incertae sedis (Argentina).

The following new combinations are proposed: Scythrisdepressa Meyrick, 1931 and Scythrisdimota Meyrick, 1931 are transferred from Scythris Hübner, 1825 to Rhamphura Landry, 1991 comb. nov. Three species classified in Scythris earlier are now classified as Scythris (incertae sedis): Scythrisdividua Meyrick, 1916, S.medullata Meyrick, 1916 and S.notorrhoa Meyrick, 1921. The taxon Syntetrernisneocompsa Meyrick, 1933, recently classified in Scythrididae: Scythris, is excluded from Scythrididae and it is now classified in Cosmopterigidae incertae sedis.

Sizing the Knowledge Gap in Taxonomy: The Last Dozen Years of Aphidiinae Research

Simple Summary

Taxonomy is a biological discipline with the task to identify, name, and describe organisms, and as such, it provides necessary data for all other biological disciplines. The biodiversity crisis through which we are living draws attention to the crucial role of taxonomy in biology today. At the same time, the scientific community, as well as society in general, has become more aware of the difficulties associated with taxonomy, such as gaps in taxonomic knowledge, a lack of taxonomic infrastructure, and an insufficient number of taxonomic experts (“taxonomic impediment”). With this study, we tried to size this knowledge gap by analyzing the taxonomical studies on Aphidiinae (Hymenoptera: Braconidae) conducted from 2010 to 2021. Aphidiinae are endoparasitoids of aphids; a single specimen completes its development inside the living aphid host, which are used in biological control programs. Here, we summarize the knowledge gathered over the last dozen years and discuss it in a general context.

Abstract

Taxonomic impediment is one of the main roadblocks to managing the current biodiversity crisis. Insect taxonomy is the biggest contributor to the taxonomic impediment, both in terms of the knowledge gap and the lack of experts. With this study, we tried to size the knowledge gap by analyzing taxonomical studies on the subfamily Aphidiinae (Hymenoptera: Braconidae) conducted from 2010 to 2021. All available taxonomic knowledge gathered in this period is critically summarized: newly described species, detection of alien species, published identification keys, etc. All findings are discussed relative to the current state of general taxonomy. Future prospects for taxonomy are also discussed.

Current State of DNA Barcoding of Sciaroidea (Diptera)—Highlighting the Need to Build the Reference Library

Simple Summary

DNA barcoding is a method by which a specific region of the mitochondrial genome is used to quantify genetic distances within and between animal species. Most DNA barcodes of the world are assembled on the Barcode of Life online database BoldSystems (BOLD). There, machine-generated barcode index numbers (BINs) are automatically assigned to clusters of specimens thought to represent species. I review the current state of DNA barcoding of the superfamily Sciaroidea, a diverse insect group consisting of close to 16,000 described fly species in eight families. To date, over 1.2 million specimens of Sciaroidea have been barcoded and the 56,648 assigned BINs on BOLD already represent 3.5 times the number of described species. Still, 95% of the BINs have currently no associated scientific name and very little effort has been put into building a quality-checked reference library where named species are linked to the BINs on BOLD. In the Nordic region, however, substantial progress is made towards building a complete reference library. While DNA barcoding has tremendous potential for advancing the knowledge for many diverse groups of insects, its potential will never be fully reached absent more engagement of trained taxonomists to build voucher collections, curate the reference libraries, and describe new species.

Abstract

DNA barcoding has tremendous potential for advancing species knowledge for many diverse groups of insects, potentially paving way for machine identification and semi-automated monitoring of whole insect faunas. Here, I review the current state of DNA barcoding of the superfamily Sciaroidea (Diptera), a diverse group consisting of eight understudied fly families where the described species in the world makes up some 10% (≈16,000 species) of all Diptera. World data of Sciaroidea were extracted from the Barcode of Life online database BoldSystems (BOLD) and contrasted with results and experiences from a Nordic project to build the reference library. Well over 1.2 million (1,224,877) Sciaroidea specimens have been submitted for barcoding, giving barcode-compliant sequences resulting in 56,648 so-called barcode index numbers (BINs, machine-generated proxies for species). Although the BINs on BOLD already represent 3.5 times the number of described species, merely some 2850 named species (described or interim names, 5% of the BINs) currently have been assigned a BIN. The other 95% remain as dark taxa figuring in many frontier publications as statistics representing proxies for species diversity within a family. In the Nordic region, however, substantial progress has been made towards building a complete reference library, currently making up 55% of all named Sciaroidea BINs on BOLD. Another major source (31%) of named Sciaroidea BINs on BOLD comes from COI sequences mined from GenBank, generated through phylogenetic and integrative studies outside of BOLD. Building a quality reference library for understudied insects such as Sciaroidea requires heavy investment, both pre sequence and post sequence, by trained taxonomists to build and curate voucher collections, to continually improve the quality of the data and describe new species. Only when the BINs are properly calibrated by a rigorously quality-checked reference library can the great potential of both classical taxonomic barcoding, metabarcoding, and eDNA ecology be realized.

Species boundaries in the messy middle-A genome-scale validation of species delimitation in a recently diverged lineage of coastal fog desert lichen fungi

Species delimitation among closely related species is challenging because traditional phenotype-based approaches, for example, using morphology, ecological, or chemical characteristics, may not coincide with natural groupings. With the advent of high-throughput sequencing, it has become increasingly cost-effective to acquire genome-scale data which can resolve previously ambiguous species boundaries. As the availability of genome-scale data has increased, numerous species delimitation analyses, such as BPP and SNAPP+Bayes factor delimitation (BFD*), have been developed to delimit species boundaries. However, even empirical molecular species delimitation approaches can be biased by confounding evolutionary factors, for example, hybridization/introgression and incomplete lineage sorting, and computational limitations. Here, we investigate species boundaries and the potential for micro-endemism in a lineage of lichen-forming fungi, Niebla Rundel & Bowler, in the family Ramalinaceae by analyzing single-locus and genome-scale data consisting of (a) single-locus species delimitation analysis using ASAP, (b) maximum likelihood-based phylogenetic tree inference, (c) genome-scale species delimitation models, e.g., BPP and SNAPP+BFD, and (d) species validation using the genealogical divergence index (gdi). We specifically use these methods to cross-validate results between genome-scale and single-locus datasets, differently sampled subsets of genomic data and to control for population-level genetic divergence. Our species delimitation models tend to support more speciose groupings that were inconsistent with traditional taxonomy, supporting a hypothesis of micro-endemism, which may include morphologically cryptic species. However, the models did not converge on robust, consistent species delimitations. While the results of our analysis are somewhat ambiguous in terms of species boundaries, they provide a valuable perspective on how to use these empirical species delimitation methods in a nonmodel system. This study thus highlights the challenges inherent in delimiting species, particularly in groups such as Niebla, with complex, relatively recent phylogeographic histories.

Diagnosing diagnoses - can we improve our taxonomy?

Taxonomic diagnoses should be clear but minimal statements that precisely distinguish a given specimen from other taxa at the same stage of development (e.g., pupa, adult female, egg). Presently, most diagnoses are of uncertain value. It is a great advantage for readers to be able to simply and confidently confirm their identifications after using a key.

ONTbarcoder and MinION barcodes aid biodiversity discovery and identification by everyone, for everyone

BACKGROUND

DNA barcodes are a useful tool for discovering, understanding, and monitoring biodiversity which are critical tasks at a time of rapid biodiversity loss. However, widespread adoption of barcodes requires cost-effective and simple barcoding methods. We here present a workflow that satisfies these conditions. It was developed via "innovation through subtraction" and thus requires minimal lab equipment, can be learned within days, reduces the barcode sequencing cost to < 10 cents, and allows fast turnaround from specimen to sequence by using the portable MinION sequencer.

RESULTS

We describe how tagged amplicons can be obtained and sequenced with the real-time MinION sequencer in many settings (field stations, biodiversity labs, citizen science labs, schools). We also provide amplicon coverage recommendations that are based on several runs of the latest generation of MinION flow cells ("R10.3") which suggest that each run can generate barcodes for > 10,000 specimens. Next, we present a novel software, ONTbarcoder, which overcomes the bioinformatics challenges posed by MinION reads. The software is compatible with Windows 10, Macintosh, and Linux, has a graphical user interface (GUI), and can generate thousands of barcodes on a standard laptop within hours based on only two input files (FASTQ, demultiplexing file). We document that MinION barcodes are virtually identical to Sanger and Illumina barcodes for the same specimens (> 99.99%) and provide evidence that MinION flow cells and reads have improved rapidly since 2018.

CONCLUSIONS

We propose that barcoding with MinION is the way forward for government agencies, universities, museums, and schools because it combines low consumable and capital cost with scalability. Small projects can use the flow cell dongle ("Flongle") while large projects can rely on MinION flow cells that can be stopped and re-used after collecting sufficient data for a given project.

Mangroves are an overlooked hotspot of insect diversity despite low plant diversity

BACKGROUND

The world's fast disappearing mangrove forests have low plant diversity and are often assumed to also have a species-poor insect fauna. We here compare the tropical arthropod fauna across a freshwater swamp and six different forest types (rain-, swamp, dry-coastal, urban, freshwater swamp, mangroves) based on 140,000 barcoded specimens belonging to ca. 8500 species.

RESULTS

We find that the globally imperiled habitat "mangroves" is an overlooked hotspot for insect diversity. Our study reveals a species-rich mangrove insect fauna (>3000 species in Singapore alone) that is distinct (>50% of species are mangrove-specific) and has high species turnover across Southeast and East Asia. For most habitats, plant diversity is a good predictor of insect diversity, but mangroves are an exception and compensate for a comparatively low number of phytophagous and fungivorous insect species by supporting an unusually rich community of predators whose larvae feed in the productive mudflats. For the remaining tropical habitats, the insect communities have diversity patterns that are largely congruent across guilds.

CONCLUSIONS

The discovery of such a sizeable and distinct insect fauna in a globally threatened habitat underlines how little is known about global insect biodiversity. We here show how such knowledge gaps can be closed quickly with new cost-effective NGS barcoding techniques.