First results of the German Barcode of Life (GBOL) - Myriapoda project: Cryptic lineages in German Stenotaenialinearis (Koch, 1835) (Chilopoda, Geophilomorpha)

Genetic diversity varies with species traits and latitude in predatory soil arthropods (Myriapoda: Chilopoda)

Aim

To investigate the drivers of intra-specific genetic diversity in centipedes, a group of ancient predatory soil arthropods.

Location

Asia, Australasia and Europe.

Time Period

Present.

Major Taxa Studied

Centipedes (Class: Chilopoda).

Methods

We assembled a database of 1245 mitochondrial cytochrome c oxidase subunit I sequences representing 128 centipede species from all five orders of Chilopoda. This sequence dataset was used to estimate genetic diversity for centipede species and compare its distribution with estimates from other arthropod groups. We studied the variation in centipede genetic diversity with species traits and biogeography using a beta regression framework, controlling for the effect of shared evolutionary history within a family.

Results

A wide variation in genetic diversity across centipede species (0-0.1713) falls towards the higher end of values among arthropods. Overall, 27.57% of the variation in mitochondrial COI genetic diversity in centipedes was explained by a combination of predictors related to life history and biogeography. Genetic diversity decreased with body size and latitudinal position of sampled localities, was greater in species showing maternal care and increased with geographic distance among conspecifics.

Main Conclusions

Centipedes fall towards the higher end of genetic diversity among arthropods, which may be related to their long evolutionary history and low dispersal ability. In centipedes, the negative association of body size with genetic diversity may be mediated by its influence on local abundance or the influence of ecological strategy on long-term population history. Species with maternal care had higher genetic diversity, which goes against expectations and needs further scrutiny. Hemispheric differences in genetic diversity can be due to historic climatic stability and lower seasonality in the southern hemisphere. Overall, we find that despite the differences in mean genetic diversity among animals, similar processes related to life-history strategy and biogeography are associated with the variation within them.

Using Malaise Traps and Metabarcoding for Biodiversity Assessment in Vineyards: Effects of Weather and Trapping Effort

Metabarcoding is a powerful tool for ecological studies and monitoring that might provide a solution to the time-consuming taxonomic identification of the vast diversity of insects. Here, we assess how ambient weather conditions during Malaise trap exposure and the effort of trapping affect biomass and taxa richness in vineyards. Biomass varied by more than twofold with weather conditions. It increased with warmer and drier weather but was not significantly related with wind or precipitation. Taxa richness showed a saturating relationship with increasing trapping duration and was influenced by environmental and seasonal effects. Taxa accumulation was high, increasing fourfold from three days of monthly trap exposure compared to continuous trapping and nearly sixfold from sampling at a single site compared to 32 sites. The limited saturation was mainly due to a large number of singletons, such as rare species, in the metabarcoding dataset. Metabarcoding can be key for long-term insect monitoring. We conclude that single traps operated for up to ten days per month are suitable to monitor the presence of common species. However, more intensive trapping is necessary for a good representation of rare species in biodiversity monitoring. The data collected here can potentially guide the design of monitoring studies.

Toward a standardized quantitative and qualitative insect monitoring scheme

The number of insect species and insect abundances decreased severely during the past decades over major parts of Central Europe. Previous studies documented declines of species richness, abundances, shifts in species composition, and decreasing biomass of flying insects. In this study, we present a standardized approach to quantitatively and qualitatively assess insect diversity, biomass, and the abundance of taxa, in parallel. We applied two methods: Malaise traps, and automated and active light trapping. Sampling was conducted from April to October 2018 in southern Germany, at four sites representing conventional and organic farming. Bulk samples obtained from Malaise traps were further analyzed using DNA metabarcoding. Larger moths (Macroheterocera) collected with light trapping were further classified according to their degree of endangerment. Our methods provide valuable quantitative and qualitative data. Our results indicate more biomass and higher species richness, as well as twice the number of Red List lepidopterans in organic farmland than in conventional farmland. This combination of sampling methods with subsequent DNA metabarcoding and assignments of individuals according depending on ecological characteristics and the degree of endangerment allows to evaluate the status of landscapes and represents a suitable setup for large-scale long-term insect monitoring across Central Europe, and elsewhere.

A DNA barcode library for 5,200 German flies and midges (Insecta: Diptera) and its implications for metabarcoding-based biomonitoring

This study summarizes results of a DNA barcoding campaign on German Diptera, involving analysis of 45,040 specimens. The resultant DNA barcode library includes records for 2,453 named species comprising a total of 5,200 barcode index numbers (BINs), including 2,700 COI haplotype clusters without species‐level assignment, so called “dark taxa.” Overall, 88 out of 117 families (75%) recorded from Germany were covered, representing more than 50% of the 9,544 known species of German Diptera. Until now, most of these families, especially the most diverse, have been taxonomically inaccessible. By contrast, within a few years this study provided an intermediate taxonomic system for half of the German Dipteran fauna, which will provide a useful foundation for subsequent detailed, integrative taxonomic studies. Using DNA extracts derived from bulk collections made by Malaise traps, we further demonstrate that species delineation using BINs and operational taxonomic units (OTUs) constitutes an effective method for biodiversity studies using DNA metabarcoding. As the reference libraries continue to grow, and gaps in the species catalogue are filled, BIN lists assembled by metabarcoding will provide greater taxonomic resolution. The present study has three main goals: (a) to provide a DNA barcode library for 5,200 BINs of Diptera; (b) to demonstrate, based on the example of bulk extractions from a Malaise trap experiment, that DNA barcode clusters, labelled with globally unique identifiers (such as OTUs and/or BINs), provide a pragmatic, accurate solution to the “taxonomic impediment”; and (c) to demonstrate that interim names based on BINs and OTUs obtained through metabarcoding provide an effective method for studies on species‐rich groups that are usually neglected in biodiversity research projects because of their unresolved taxonomy.

A synopsis of Estonian myriapod fauna (Myriapoda: Chilopoda, Diplopoda, Symphyla and Pauropoda)

The data on Estonian Myriapoda are scattered in various publications and there has been no overview of the fauna up to the present. A critical summary of the previous information on Estonian Myriapoda is given, supplemented by new records and distribution maps. Altogether, 5784 specimens from 276 collecting sites were studied. To the hitherto recorded 14 centipede species are added Lithobiusmelanops, L.microps, Geophiluscarpophagus, G.flavus, Strigamiatranssilvanica and Stenotaenialinearis, a probably introduced species. Of the 27 published Estonian millipede species, the data on two species proved erroneous, and two new species were recorded (Craspedosomaraulinsii and Cylindroiulusbritannicus). Two previously recorded millipede species – Brachyiuluspusillus and Mastigophorophyllonsaxonicum – were not found in the recent samples, the latter may have become more rare or extinct. Pauropoda and Symphyla lack previous reliable records. Combined with published data, the number of myriapod species known from Estonia is now set at 52. Some changes in species distribution and frequencies were detected comparing the published data with new records. Some data about habitat preferences of the more common species are also given. The majority of species have a western Palaearctic distribution, while six species are at the northern limit of their ranges.

The subgenus Monotarsobius in the Iberian Peninsula with a description of a new pseudo-cryptic species from Northern Spain revealed by an integrative revision of Lithobius crassipes L. Koch, 1862 (Chilopoda, Lithobiomorpha, Lithobiidae)

The widespread European centipede species Lithobius (Monotarsobius) crassipes L. Koch, 1862 was revised using an integrative approach incorporating sequence data and morphology. The partial mitochondrial cytochrome c oxidase subunit I (COI) barcoding gene was amplified and sequenced for 21 individuals from northern Spain, France and Germany as well as for individuals of three other species of the subgenus Monotarsobius Verhoeff, 1905. The dataset was used for molecular phylogenetic analysis and genetic distance determination. In addition, Monotarsobius specimens from more than 100 localities in northern Spain, France, and Germany were morphologically investigated. Both morphological and molecular data indicate that specimens from the Navarre and Gipuzkoa provinces, northern Spain, represent a distinct pseudo-cryptic species, only differing in some minor characters from L.crassipes. The new species L. (Monotarsobius) crassipesoidessp. n. is described and compared to L.crassipes in detail using morphology and morphometric statistics for body, head, and antennae length, number of ocelli and coxal pores, as well as the starting leg for legpair spines Vmt and DaP. The Iberian and European records of L.crassipes are discussed. The subspecies L.crassipesmorenoi Garcia Ruiz, 2014 from Southern Spain is elevated to species as L.morenoistat. n. A checklist, distribution map and key to all five species of Monotarsobius of the Iberian Peninsula are presented.

Local Hotspots of Endemism or Artifacts of Incorrect Taxonomy? The Status of Microendemic Pill Millipede Species of the Genus Glomeris in Northern Italy (Diplopoda, Glomerida)

Local endemic species with their unique evolutionary history always stirred the interest of scientists. One such area especially rich in endemics is northern Italy. In case of pill millipedes of the genus Glomeris Latreille, 1803, only a single species is found in northern Europe, while 22 country-endemics alone are known from Italy. Many of these endemics, however, have not been studied in several decades; therefore we aimed to determine whether this diversity is the result of overlooked synonymies or natural processes. A focus was placed on the local endemics that are in some aspects morphologically similar to the widespread and variable G. klugii Brandt, 1833. The local endemics Glomeris larii Verhoeff, 1921, G. primordialis Verhoeff, 1930, G. oblongoguttata Verhoeff, 1894, G. oropensis Verhoeff, 1936, G. transalpina Koch, 1836, G. romana Verhoeff, 1900, G. ligurica Latzel, 1884 and G. apuana Verhoeff, 1911 were included in a molecular analysis incorporating ribosomal nuclear (28S) and mitochondrial (COI) genes. Individuals were sequenced and compared to 31 specimens from 18 localities of G. klugii. The final dataset included 657 base pairs for 56 terminals in the COI, and 14 terminals with 1068 base pairs in the combined 28S and COI analysis. Our analysis shows intraspecific distances of up to 5% in the COI gene in G. klugii that are not strictly correlated to geography or color pattern. G. larii is discovered to be genetically and morphologically identical to G. klugii and is synonymised with the latter. Interspecific distances in our dataset vary between 6.7 to 15.9%, with the lowest (6.7-9.0%) between G. primordialis and G. klugii. Our analysis confirms the species status of the local endemics G. primordialis, G. oblongoguttata, G. oropensis, G. transalpina, G. ligurica and G. apuana. We also confirm the synonymy of G. undulata Koch, 1844 under G. klugii. G. genuensis Latzel, 1886 is indistinguishable from G. ligurica.

How to tackle the molecular species inventory for an industrialized nation-lessons from the first phase of the German Barcode of Life initiative GBOL (2012-2015)

Biodiversity loss is mainly driven by human activity. While concern grows over the fate of hot spots of biodiversity, contemporary species losses still prevail in industrialized nations. Therefore, strategies were formulated to halt or reverse the loss, driven by evidence for its value for ecosystem services. Maintenance of the latter through conservation depends on correctly identified species. To this aim, the German Federal Ministry of Education and Research is funding the GBOL project, a consortium of natural history collections, botanic gardens, and universities working on a barcode reference database for the country's fauna and flora. Several noticeable findings could be useful for future campaigns: (i) validating taxon lists to serve as a taxonomic backbone is time-consuming, but without alternative; (ii) offering financial incentives to taxonomic experts, often citizen scientists, is indispensable; (iii) completion of the libraries for widespread species enables analyses of environmental samples, but the process may not hold pace with technological advancements; (iv) discoveries of new species are among the best stories for the media; (v) a commitment to common data standards and repositories is needed, as well as transboundary cooperation between nations; (vi) after validation, all data should be published online via the BOLD to make them searchable for external users and to allow cross-checking with data from other countries.

Barcoding of Central European Cryptops centipedes reveals large interspecific distances with ghost lineages and new species records from Germany and Austria (Chilopoda, Scolopendromorpha)

In order to evaluate the diversity of Central European Myriapoda species in the course of the German Barcode of Life project, 61 cytochrome c oxidase I sequences of the genus Cryptops Leach, 1815, a centipede genus of the order Scolopendromorpha, were successfully sequenced and analyzed. One sequence of Scolopendra cingulata Latreille, 1829 and one of Theatops erythrocephalus Koch, 1847 were utilized as outgroups. Instead of the expected three species (Cryptops parisi Brolemann, 1920; Cryptops anomalans Newport, 1844; Cryptops hortensis (Donovan, 1810)), analyzed samples included eight to ten species. Of the eight clearly distinguishable morphospecies of Cryptops, five (Cryptops parisi; Cryptops croaticus Verhoeff, 1931; Cryptops anomalans; Cryptops umbricus Verhoeff, 1931; Cryptops hortensis) could be tentatively determined to species level, while a further three remain undetermined (one each from Germany, Austria and Croatia, and Slovenia). Cryptops croaticus is recorded for the first time from Austria. A single specimen (previously suspected as being Cryptops anomalans), was redetermined as Cryptops umbricus Verhoeff, 1931, a first record for Germany. All analyzed Cryptops species are monophyletic and show large genetic distances from one another (p-distances of 13.7-22.2%). Clear barcoding gaps are present in lineages represented by >10 specimens, highlighting the usefulness of the barcoding method for evaluating species diversity in centipedes. German specimens formally assigned to Cryptops parisi are divided into three clades differing by 8.4-11.3% from one another; their intra-lineage genetic distance is much lower at 0-1.1%. The three clades are geographically separate, indicating that they might represent distinct species. Aside from Cryptops parisi, intraspecific distances of Cryptops spp. in Central Europe are low (<3.3%).