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Soil invertebrates are among the least understood metazoans on Earth. Thus far, the lack of taxonomically broad and dense genomic resources has made it hard to thoroughly investigate their evolution and ecology. With MetaInvert we provide draft genome assemblies for 232 soil invertebrate species, representing 14 common groups and 94 families. We show that this data substantially extends the taxonomic scope of DNA- or RNA-based taxonomic identification. Moreover, we demonstrate that theories of genome evolution cannot be generalised across evolutionarily distinct invertebrate groups. The soil invertebrate genomes presented here will support the management of soil biodiversity through molecular monitoring of community composition and function, and the discovery of evolutionary adaptations to the challenges of soil conditions.

Although soil ecology has benefited from recent advances in describing the functional and trophic traits of soil organisms, large scale reconstruction of soil food webs is still hampered by the issues that (1) most of the data about trophic interactions and diets are distributed across heterogeneous repositories, (2) no well-established terminology exists for describing trophic groups, feeding processes, and resource types, and (3) large heterogeneity exists in the trophic classification of different soil organisms, or such classifications are lacking. Here, we propose the Soil Food Web Ontology as a new formal framework for representing knowledge on trophic ecology of soil organisms. This ontology captures the semantics of trophic concepts, including consumer-resource interactions, diets and feeding processes, and provides a formalisation of trophic group definitions. This ontology can be used to add semantic annotations to trophic data, thus facilitating the integration of heterogeneous datasets. It also provides lexical resources that can support the development of information extraction tools for the creation of literature-based datasets. Finally, it enables automatic and consistent classification of soil organisms based on their trophic relationships. We argue that, by harmonising the terminology and underlying concepts of soil trophic ecology, our ontology allows a better use of available information on the feeding habits of soil organisms and sounder trophic classifications, thus facilitating the reconstruction of soil food webs and making food web research more accessible, reusable and reproducible.

Punctoribates is one of few genera in Poronota (Acari: Oribatida) containing species with porose areas and species with saccules, the two types of the octotaxic system. These porose organs are the main difference between two morphologically similar species, P. punctum with porose areas and P. zachvatkini with saccules. As the octotaxic system can vary within species, species separation solely based on this trait might be insufficient. To assess the species status of P. zachvatkini, we investigated additional differences from P. punctum by comparing habitat preferences of the two species regarding nature reserves and agricultural landscapes during a field study in the German Eifel region, and by examining Punctoribates material from four large German natural history museums. We also performed scanning electron microscopy (SEM) and a genetic analysis using the D3 marker of the nuclear 28S rDNA gene. In the field study, P. zachvatkini had higher densities in the nature reserves and P. punctum in the agricultural landscapes. Evaluation of the museum material revealed P. punctum occurred more regularly in disturbed sites such as urban, agricultural and post-mining areas compared to P. zachvatkini. Pairwise distances of the 28S D3 genetic marker as well as an additional base pair in P. zachvatkini further support the separation of the two species, and SEM investigations revealed new details regarding the punctulation of P. zachvatkini. The review of the museum material showed that P. zachvatkini already occurred in Germany in 1967 and has a wider distribution than previously known.

Open-cast coal-mining creates a severe disturbance of ecological systems, resulting in post-mining areas that have lost their soils entirely and are exposed to extreme conditions. Nonetheless, these areas allow us to investigate the process of primary succession. We studied the first 12 years of soil tardigrade succession at ‘Chicken Creek’, an experimental site within the open-cast coal-mining area in Welzow Süd, Germany. A total of ten tardigrade genera and 13 species or species groups were identified at the site. Over time, the organic carbon content, proportion of silt and nutrient availability in the soil increased, and the soil particle size distribution and pH value changed significantly. The vegetation cover and nematode abundance increased, whereas tardigrade densities peaked in 2008 and decreased thereafter, as did their mean body size. Species replacement was obvious within this 12 year study period, and tardigrade species diversity increased, indicating that ecological niche diversity also increased throughout this time. Vegetation cover, soil particle size distribution and time were the most important factors influencing the tardigrade community. We also discuss further potential factors and the ability of terrestrial tardigrades to persist despite many environmental constraints, such as fluctuations in pH and moisture, and to colonize new habitats faster than most other animal groups.

Metagenomics - shotgun sequencing of all DNA fragments from a community DNA extract - is routinely used to describe the composition, structure and function of microorganism communities. Advances in DNA sequencing and the availability of genome databases increasingly allow the use of shotgun metagenomics on eukaryotic communities. Metagenomics offers major advances in the recovery of biomass relationships in a sample, in comparison to taxonomic marker gene based approaches (metabarcoding). However, little is known about the factors which influence metagenomics data from eukaryotic communities, such as differences among organism groups, the properties of reference genomes and genome assemblies.We evaluated how shotgun metagenomics records composition and biomass in artificial soil invertebrate communities. We generated mock communities of controlled biomass ratios from 28 species from all major soil mesofauna groups: mites, springtails, nematodes, tardigrades and potworms. We shotgun-sequenced these communities and taxonomically assigned them with a database of over 270 soil invertebrate genomes.We recovered 90% of the species, and observed relatively high false positive detection rates. We found strong differences in reads assigned to different taxa, with some groups (e.g. springtails) consistently attracting more hits than others (e.g. enchytraeids). Original biomass could be predicted from read counts after considering these taxon-specific differences. Species with larger genomes, and with more complete assemblies consistently attracted more reads than species with smaller genomes. The GC content of the genome assemblies had no effect on the biomass-read relationships.The results show considerable differences in taxon recovery and taxon specificity of biomass recovery from metagenomic sequence data. The properties of reference genomes and genome assemblies also influence biomass recovery, and they should be considered in metagenomic studies of eukaryotes. We provide a roadmap for investigating factors which influence metagenomics-based eukaryotic community reconstructions. Understanding these factors is timely as accessibility of DNA sequencing, and momentum for reference genomes projects show a future where the taxonomic assignment of DNA from any community sample becomes a reality.

The present study gives the first detailed results on the partner-finding behaviour of tardigrades. We investigated whether the finding of mating partners by Isohypsibius dastychi followed certain criteria that are expected if pheromone signals are involved. For this purpose, tardigrade pairs were positioned in an arena, at a range of distances from each other. Only those females that were ready for mating attracted the male. The smaller the initial distance between them, the more directly the male headed for the female. The route travelled and time taken increased exponentially with increasing initial distance between partners, which means that the male lost orientation with respect to the female the larger the distance between the pair became. The findings indirectly suggest a yet undetermined female pheromone, which produces a concentration gradient in the water and loses strength quickly in terms of distance. Our assumption is supported by rare observations of sperm release without direct contact between partners that nevertheless resulted in fertile offspring. The observation that the female partners in this no-contact mating behaviour then deposited their eggs (a behaviour that was never seen when males were absent) suggests that they, likewise, can sense a fresh ejaculate of spermatozoa in their direct vicinity.

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios., This research was supported by a grant from DOB Ecology to T.W.C., a grant from the Netherlands Organization for Scientific Research (grant 016.Veni.181.078) to S.G., grants from NSF (OPP 1115245, 1341736, 0840979) to B.J.A., by a Ramon y Cajal fellow award (RYC-2016-19939) to R.C.H., a grant from UNEP & Global Environment Facility to J.E.C., a grant from NERC (NE/M017036/1) to T.C., a grant from FAPEMIG/FAPESP/VALE S.A.(CRA-RDP-00136-10) to L.B.C., through the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) awarded to S.R.C., a grant from CNPq PROTAX (562346/2010-4) to J.M.d.C.C., a grant from DFG (CRC990) to V.K. and S.S., a grant from the MSHE of Russia (AAAA-A17-117112850234-5) to A.A.K., grants from the Chinese Academy of Sciences (XDB15010402) and the National Natural Science Foundation of China (41877047) to Q.L., grants from the National Natural Science Foundation of China (31330011, 31170484) to W.L., grants from NERC (NE/M017036/1) to M.M., grants from the Spanish Ministry of Innovation (CGL2009-14686-C02-01/ 02, CGL2013-43675-P) to J.A.R.M., grants from NSF (DEB-0450537, DEB-1145440) to P.M., T.O.P. and K. Powers, grants from the German Academic Exchange Service (PKZ 91540366) and NAFOSTED (106.05 – 2017.330) to T.A.D.N., by an ARC Discovery project (DP150104199) to U.N.N., by the National Key Research and Development Program of China (2016YFC0502101) and the National Natural Science Foundation of China (31370632) to K. Pan, a grant from the Natural Environment Research Council (NERC) to D.G.W., a grant from BAPHIQ (106AS-9.5.1-BQ-B3) J.-i.Y. The James Hutton Institute receives financial support from the Scottish Government Rural and Environment Science and Analytical Services (RESAS) division. Investigations in northwest Russia were carried out under state order for IB KarRC RAS and are partially supported by the Russian Foundation for Basic Research (18-34-00849). We thank E. Clark and A. Orgiazzi for review of the manuscript; and R. Bouharroud, Z. Ferji, L. Jackson and E. Mzough for providing data.

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns., This research was supported by a grant from DOB Ecology to T.W.C., a grant from the Netherlands Organization for Scientific Research (grant 016.Veni.181.078) to S.G., grants from NSF (OPP 1115245, 1341736, 0840979) to B.J.A., by a Ramon y Cajal fellow award (RYC-2016-19939) to R.C.H., a grant from UNEP & Global Environment Facility to J.E.C., grants from NERC’s Soil Security Programme to R.D.B. (NE/M017028/1) T.C. (NE/M017036/1), a grant from FAPEMIG/FAPESP/VALE S.A.(CRA-RDP-00136-10) to L.B.C., through the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) awarded to S.R.C., a grant from CNPq PROTAX (562346/2010-4) to J.M.d.C.C., a grant from DFG (CRC990) to V.K. and S.S., a grant from the MSHE of Russia (AAAA-A17-117112850234-5) to A.A.K., grants from the Chinese Academy of Sciences (XDB15010402) and the National Natural Science Foundation of China (41877047) to Q.L., grants from the National Natural Science Foundation of China (31330011, 31170484) to W.L., grants from NERC (NE/ M017036/1) to M.M., grants from the Spanish Ministry of Innovation (CGL2009-14686-C02-01/02, CGL2013- 43675-P) to J.A.R.M., grant from the Spanish Ministry of Innovation (RYC-2016-19939) to R.C.H., grants from NSF (DEB-0450537, DEB-1145440) to P.M., T.O.P. and K. Powers, grants from the German Academic Exchange Service (PKZ 91540366) and NAFOSTED (106.05–2017.330) to T.A.D.N., by an ARC Discovery project (DP150104199) to U.N.N., by the National Key Research and Development Program of China (2016YFC0502101) and the National Natural Science Foundation of China (31370632) to K. Pan, a ERC Research Council Advanced grant (ERC-Adv 323020 SPECIALS) to W.H.v.d.P, a grant from the Natural Environment Research Council (NERC) to D.G.W., a grant from BAPHIQ (106AS-9.5.1-BQ-B3) to J.-i.Y., a grant from the Russian Foundation for Basic Research (18-29-05076) to A.V.T. The James Hutton Institute receives financial support from the Scottish Government Rural and Environment Science and Analytical Services (RESAS) division. Investigations in Northwest Russia were carried out under state order for IB KarRC RAS and are partially supported by the Russian Foundation for Basic Research (18-34-00849).

Zusammenfassung Nematoden spielen nicht nur als Parasiten in Mensch, Tier und Pflanze eine – wenn auch negative – so doch herausragende Rolle. Sie wirken vor allem als ausgesprochene Nutzlinge fur uns: Sie sind als wichtiger, naturlicher Bestandteil des Nahrungsnetzes masgeblich und unverzichtbar am Nahrstoffkreislauf beteiligt. Auserdem setzen wir sie in zunehmendem Mase gewinnbringend in der biologischen Schadlingsbekampfung, der okotoxikologischen Bewertung von Boden und Sedimenten und als ausgezeichnete Modellorganismen fur die Forschung ein.

Reliable and well-developed DNA barcode databases are indispensable for the identification of microscopic life. However, effectiveness of molecular barcoding in identifying terrestrial specimens, and nematodes in particular, has received little attention. In this study,ca600 ribosomal large subunit DNA fragments (D3-D5 region) were successfully amplified for 79 limnic and terrestrial nematode species sampled at 147 locations across Germany. Distinctive DNA motifs in the LSU region were identified in 80% of all species examined. For 13 supposedly single morphospecies, 2-7 LSU barcode groups were detected with a wide range of intraspecific variations (0.09-7.9%). This region seems to be more suitable for the assessment of limno-terrestrial nematode diversity than the frequently used mitochondrial geneCOI, as amplification success of the latter fragment is low for several nematode species. Our reference database for nematodes may serve as a starting point for applied and fundamental studies for these ubiquitous, ecologically highly relevant, organisms.

On the 24th January 2019 the former director of the Senckenberg Museum of Natural History Görlitz (formerly the Staatliches Museum für Naturkunde Görlitz) Prof. Dr. Wolfram Dunger passed away at the age of 89. The employees of the Museum, his colleagues and friends will always remember him as an international authority on soil zoology and as the ‘leader of the Museum’.

Phylogenetic positioning within Eutardigrada is based mainly on claw and buccopharyngeal morphology. In tardigrades that lack claws, i.e. representatives of the genus Apodibius, buccopharyngeal structures are the only morphological characters used for systematic classification. Investigating the feeding apparatus of Apodibius confusus Dastych, 1983 with light microscopy and scanning electron microscopy (SEM) techniques, the present study added morphological affirmation to the recently published molecular classification of A. confusus as a representative of Isohypsibiidae. The present study aimed to disentangle which of the Isohypsibiidae genera A. confusus is most closely related to. From a morphological point of view and with the SEM images presently available, A. confusus appears closest to Hexapodibius and Doryphoribius. The present study once more revealed the need for investigations that combine molecular and detailed morphological data to finally disentangle the phylogeny of Isohypsibiidae.

In the present study we provide new insights into the mating behaviour of a bisexual tardigrade, Isohypsibius dastychi, revealing a process much more complex than expected. Mating included mutual stimulation that preceded semen ejaculation and egg deposition. If no mating occurred, egg absorption was observed. In addition, the life history and the influence of temperature on development were studied at two temperatures (12 and 20 °C). At both temperatures I. dastychi underwent three moults until adulthood with increasing inter-moult phases from the first to the third moult. As animals maintained at 12 °C became adults significantly later and also were significantly larger than animals at 20 °C, it is unlikely that either age or size determines the transition to adulthood. Generation time of females was significantly shorter than that of males, and both males and females were iteroparous. The consequences of our findings are discussed.

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.

Der Boden ist einer der individuen- und artenreichsten Lebensraume der Erde und Ort vielfaltiger okosystemarer Dienstleistungen. Aktuelle Forschungsprojekte zur Entstehung und Entwicklung von Bodentiergemeinschaften, zu den vielfaltigen Wechselwirkungen innerhalb des Bodennahrungsnetzes und zur Verbreitung von Bodentieren geben unter anderem Einblick in die okologischen Anspruche und Anpassungsfahigkeit der Welt unter unseren Fusen und tragen so dazu bei, eine nachhaltige Nutzung der Okoressource Boden zu gewahrleisten. Soil – an underestimated biotope The soil is a biotope with high species abundances and richness. It is, furthermore, a location where important ecosystem services are realized. Recent research projects on the origin and development of soil animal communities, on the heterogeneous interactions within the soil nutrient net and the distribution of soil animals show the different ecological traits and adaptabilities of the world beneath our feet. So research contributes to maintain the eco-resource of soil and its sustainable use.

The present paper aims at providing a practical identification tool for soil zoologists. It shall facilitate taxonomic examination of tardigrade communities in order to encourage further investigations and by this expand our scarce knowledge on soil tardigrades. From faunistic studies on soil tardigrades a list of the eutardigrade species presently known from European soils was gathered comprising 22 genera, 58 species, 3 species groups. Based on the most important standard works and on up-to-date nomenclature an illustrated key to the eutardigrade genera of European soils was created. Genus descriptions and identification keys to the soil species were added while those genera that hold only one or two soil species were accomplished with short species descriptions. Additional information is given on the relevant determination features, such as claws and bucco-pharyngeal apparatus. Difficulties in tardigrade identification and taxonomy are discussed. Due to the comparably small number of studies that so far exist on soil tardigrades, the key will most likely not cover all species present in European soils, but shall provide a basis to facilitate further research.

This study focuses on the CO 2 -tolerance of soil nematodes from natural CO 2 springs (mofette fields). In laboratory experiments, we compared survival, reproduction, activity and reactivation of a CO 2 -sensitive species with a CO 2 -tolerant species. Both species survived even 100% CO 2 , but in an inactive state. The higher the CO 2 concentration the more individuals entered inactivity. We found significant differences between the two species: more adults of the CO 2 -tolerant species maintained activity and reproduction at higher CO 2 concentrations. Moreover, reactivation after inactivity was faster. Together with a higher juvenile mortality of the CO 2 -sensitive species, these interspecific differences are conclusive to explain the niche separation of the two species that was observed in the mofette field.

Mofette fields, i.e. geogenic, cold CO2-exhaling gas vents occurring naturally in regions of tectonic or volcanic disturbances provide an excellent opportunity to investigate long-term responses of the soil biota to increased CO2 concentrations. The upper centimeters of mofette soils present a small-scale mosaic of different CO2 and O2 concentrations: From up to 100% CO2 and 0% O2 around local degassing vents to ambient soil atmosphere ( Canonical correspondence analyses revealed strong correlations between soil faunal communities and environmental measures, above all CO2 concentration, organic matter content and plant coverage. An increase in CO2 concentration was followed by a steady decline in collembolan and nematode species richness and collembolan densities, but below a threshold of 62% CO2 had no significant effect on overall nematode densities. Collembolans developed viable populations at up to 20% CO2, where some mofettophilous species had their highest densities and frequencies, but other more general species also occurred (66% of overall collembolan densities). Nematodes, on the other hand, maintained individual-rich populations at up to 62% CO2, but above 20% CO2 nematode communities consisted almost entirely (97.6%) of three mofettophilous species: one feeding on bacteria, one on fungi and one on plant roots. Likely a combination of active and passive life phases together with temporal and micro-scale changes in environmental conditions allows survival of few mofettophilous species under CO2 conditions too extreme for most other species. The finding that mofettophilous species maintained denser populations in high CO2 patches, with species optima between 3% and 40% CO2, indicates that they even profit from CO2 degassing, presumably via changes in food supply or due to the lack of competitors.

The systematics of Eutardigrada, the largest lineage among the three classes of the phylum Tardigrada, is based mainly on the morphology of the leg claws and of the buccal apparatus. However, three members of the rarely recorded and poorly known limno-terrestrial eutardigrade genus Apodibius have no claws on their strongly reduced legs, a unique character among all tardigrades. This absence of all claws makes the systematic position of Apodibius one of the most enigmatic among the whole class. Until now all known associates of the genus Apodibius have been located in the incertae sedis species group or, quite recently, included into the Necopinatidae family. In the present study, phylogenetic analyses of 18S and 28S rRNA sequence data from 31 tardigrade species representing four parachelan superfamilies (Isohypsibioidea, Hypsibioidea, Macrobiotoidea, Eohypsibioidea), the apochelan Milnesium tardigradum, and the type species of the genus Apodibius, A. confusus, indicated close relationship of the Apodibius with tardigrade species recently included in the superfamily Isohypsibioidea. This result was well-supported and consistent across all markers (separate 18S rRNA, 28S rRNA, and combined 18S rRNA+28S rRNA datasets) and methods (MP, ML) applied.

In autumn 2005, the artificial catchment Chicken Creek was completed in an open-cast lignite mine in Lusatia, Germany. The 6 ha area has been constructed as a two-layer system consisting of a clay aquiclude and a sandy aquifer at the top. After construction, the site was left to an unrestricted and unmanaged succession. A comprehensive environmental monitoring program started immediately after the site was completed. Time series of essential environmental parameters were recorded with high temporal and spatial resolution. This paper presents selected time series of the past 6-year ecosystem development. Important changes registered in this period allow for the definition of distinctive phases of the still ongoing initial ecosystem evolution. A primary, short, but pronounced geo-phase—characterized by surface runoff, excessive erosion and sedimentation as well as very rapid immigration of biota—was followed by a hydrological dominated phase with processes, such as groundwater recharge. At the end of the study period, biotic processes became more evident. It can be concluded that the artificial catchment offers unique opportunities for interdisciplinary research on the establishment of an ecological system with rapidly growing complexity. The highly dynamic development of the Chicken Creek catchment provides the possibility to observe manifold changes within short time and to detect feedbacks and their modifications between different ecosystem compartments.

To examine physiological adaptations to the two combined stressors O2 deprivation and extreme CO2 concentrations, we compared respiratory responses of two nematode species occurring in natural CO2 springs. The minimum O2 concentration allowing maintenance of respiration in both species was 0.0176μmol O2ml-1 (corresponds to 1.4% O2 in air). After exposure to anoxia, individuals resumed respiration immediately when O2 was added, but on a lower level compared to control and without showing a respiratory overshoot. A species-specific response was found in respiration rate during 20% CO2: the more tolerant species maintained respiration rates, whereas the sensitive species showed a decreased respiration rate as low as after anoxia. The results indicate that during 20% CO2 the sensitive species undergo a survival state. We conclude, that the ability to maintain respiration even under low oxygen and high CO2 concentrations may allow the better adapted species to occupy an ecological niche in the field, where others cannot exist.

In the recently published checklist of plant-parasitic nematodes known from Germany (Sturhan 2014) genera and species of the order Tylenchida, which are generally considered as being parasites of higher plants, represent the largest taxonomic group with 212 species. The present paper gives an overview of the remaining trophic groups in Tylenchida: Root tip feeders, myceliophagous species and entomoparasites, the latter often having a free-living soil generation. A total of 165 species are included, most of them representatives of the suborder Hexatylina (96 species), followed by members of Tylenchina (67 species). Where available, first records for Germany are given together with data on habitat, distribution and the hosts of zooparasitic species. A high number of valid species (95) were originally described from Germany; 20 additional species have been synonymised with previously described species or are considered as species inquirendae. Published data are critically reviewed and some new records are added. Many published records are considered as questionable and need verification. Part of the species is deficiently characterised and requires further study. The number of unidentified and still undescribed species appears to be high. Two obviously new Tenunemellus species as well as a nematode population isolated from soil, which could not be attributed to any of the currently known tylenchid genera, are briefly characterised. An obviously still undescribed species of Paurodontoides is recorded and morphological characteristics are presented: it is the first record of the genus outside USA. Morphological characters of Boleodorus clavicaudatus populations from Germany are given and compared to the original description. Supplementing morphological characters of Pleurotylenchus sachsi and data on occurrence, habitat and distribution in Germany are presented. A Safianema population recovered in southern Germany, resembling S. lutonense, is briefly characterised morphologically.

In mofette fields, natural carbon dioxide springs, organisms have to stand extreme CO 2 concentrations up to 100%. These hostile conditions are spatially small-scaled and further influenced by earth tides, wind and temperature. The present project investigated the influence of increased atmospheric CO 2 concentration on spiders as representatives of above-ground organisms by means of pitfall traps in three mofette fields, differing in habitat conditions in the Plesna valley, eastern Cheb Basin, Czech Republic. Among the 71 recorded spider species four were rarely found in the Czech Republic. A canonical correspondence analysis revealed significant influences of environmental parameters on the spider assemblages. Two groups of spiders are clearly distinguishable, one being positively influenced by humidity and the second by temperature. A cluster analysis showed distinct and congruent results: spider assemblages of pitfall traps at spots with a mean CO 2 concentration above 7.6% grouped close together and this grouping was independent of site. At >7.6% CO 2 significantly fewer individuals and species were found in comparison to areas with lower CO 2 concentration. Between 2.5 and 10% CO 2 , spiders indicated increased CO 2 concentrations much more sensitively than endogeic organisms (Nematoda, Collembola) in a nearby mofette field. Unlike in nematodes, collembolans and plants, no mofettovageous or mofettophilous spiders were detected. In contrast to humidity, CO 2 concentration and temperature, the vegetation cover was not among the factors, which significantly influenced spiders. This is explained by the fact that mofettophilous plants occurred at spots where almost no spiders could live. In a field experiment, most Pardosa pullata males tested passed a 30 cm long corridor with increased carbon dioxide concentration. These results and that of pitfall traps showed that relatively large and wandering specimens respectively were able to transit moderately hostile spots. Further experiments are necessary to find out if there is any active avoidance of high-CO 2 areas by spiders.

Soil organisms contribute considerably to soil formation, fertility and microstructure of young soils. Oribatid mites as a part of the soil mesofauna are able to colonize young soils within a few years, but little is known about their dispersal pathways. In particular, the role of active dispersal during the colonization of young soils is almost unknown. The aims of the present study were (1) to determine the distance of active above-ground dispersal by oribatid mites in bare test plots with pure substrate using mini-pitfall traps in different distances to the source substrate (meadow), (2) to determine active below-ground movement using minicontainer traps in different distances to the meadow, (3) to calculate species-specific dispersal rates, and (4) to compare the contribution of wind-dispersal (investigated in a former study) as well as active above- and below-ground movement to the species assemblage dispersing into the bare plots. The results demonstrate that active migration occurs both above- as well as below-ground. From 31 species in the adjacent meadow, 17 immigrated into the bare test plots. The number of specimens and species actively moving above-ground significantly decreased with increasing distance along the bare substrate. Dispersal rates were species specific and varied between 0.3 and 2.1 cm/day. The number of specimens actively moving below-ground was low. However, relative to the low specimen number the number of species was high. Particularly members of the Suctobelbidae and Oppiidae actively moved into the bare plots below-ground. Dispersal mechanisms were found to be species specific, as about 32% of the registered species moved actively below-ground, 32% moved actively above-ground and about 26% combined active movement and passive wind-dispersal. In conclusion, active dispersal is an important dispersal mechanism in the colonization of young soils. However, several species combine different dispersal mechanisms, so that the number of possible dispersal pathways is one factor that determines specimen- and species-richness in a newly found habitat.

Oribatid mites are important colonizers of young soils, but little is known about their immigration pathways. In this study, one often-stated hypothesis was tested quantitatively: that wind is an important dispersal pathway. The aim was (1) to detect wind dispersal in oribatid mites (using sticky traps at different heights above ground level) and to determine factors influencing wind dispersal, (2) to investigate whether oribatids can survive wind dispersal and immigrate by wind into young soils (using mini-pitfall traps in test plots with oribatid-free substrate, active immigration being prohibited) and (3) to find out whether those oribatids are able to colonize young soils (using soil cores from the test plots). The results demonstrate (1) that mainly arboreal oribatid species were dispersed by wind – even at 160 m height – and can therefore be spread over large distances. Nevertheless, about 10% of the wind-dispersed oribatid mites belonged to species able to live in the soil and may therefore be potential colonizers of young soils. The number of specimen and species transported by wind was the highest close to the soil surface and the number of dispersed individuals was mainly influenced by seasonality and humidity. The results also suggest that the probability of a soil oribatid being dispersed by wind depends on its original microhabitat (tree habitats > soil surface > deeper soil layers) and its body weight. It was also shown that soil-dwelling oribatid mites survived wind dispersal and immigrated by wind into the test plots and that colonization of the test plots took at least 2 months longer than immigration. However, colonization success was low during the first 2 years of investigation and only Trichoribates incisellus was found several times in the nutrient-poor substrate. Therefore, wind dispersal is an important migration pathway, especially for arboreal oribatids. We suggest that immigration into young soils most likely occurs by repeated short-distance dispersal. Only some species are able to survive the hostile conditions of wind dispersal as well as of pioneer soils, but those that do are potentially the founders of new populations.

At the coal-mining site ‘Chicken Creek’ (Spremberg, Germany), primary succession of the soil tardigrade community was investigated over a period of 4 years after initial soil deposition in 2005. During the first 2 years of succession, tardigrades occurred only sporadically and in very small numbers. In October 2007, algal-feeding Apodibius confusus first appeared at the site with small-scale mass densities of up to 2281 individuals in only 10 cm2 of top soil. A. confusus from then on dominated the soils (98% of overall tardigrade counts). From October 2007 to May 2009, its distribution changed from patchy to homogenously and its mean densities gradually increased to 328.7 thousand tardigrades m−2. In May 2009, A. confusus was present in 100% of the samples, while at the same time, new tardigrade species became established, the second frequent species being Hexapodibius cf. micronyx (3% of overall counts). With A. confusus and H. cf. micronyx, two tardigrades with reduced claws inhabit the ‘Chicken Creek’ sites: complete lack of claws in the genus Apodibius and 4th pair of claws missing in the genus Hexapodibius. The use of claws in the pore system of coarse soil substrates and the necessity to clarify the position of Apodibius and Hexapodibius in the system of Tardigrada is discussed. At the moment, we intend to culture A. confusus to observe its locomotion and to provide life history data and alternative food sources of the species. Zusammenfassung Auf der Flache Huhnerwasser im Braunkohletagebau bei Spremberg (Deutschland) wurde die Primarsukzession der Bodentardigraden wahrend der ersten vier Jahre nach Schuttung der Flache in 2005 untersucht. In den ersten beiden Sukzessionsjahren kamen Tardigraden nur sporadisch und in kleinen Zahlen vor. Im Oktober 2007 erschien dann der Algenfresser Apodibius confusus auf der Flache mit punktuellen Massenvorkommen von bis zu 2281 Tieren in nur 10 cm2 Schuttsubstrat. Von diesem Zeitpunkt an dominierte A. confusus die Schuttsubstrate (98% der Tardigradenabundanzen). Zwischen Oktober 2007 und Mai 2009 wandelte sich seine Verteilung von verstreut zu homogen, und seine mittleren Dichten nahmen graduell bis 328700 Individuen m−2 zu. Im Mai 2009 wurde A. confusus schlieslich in 100% der Proben nachgewiesen. Zur gleichen Zeit etablierten sich auf der Flache auch andere Tardigradenarten, wie zum Beispiel Hexapodibius cf. micronyx, mit 3% der Gesamtabundanz die zweithaufigste Art. Mit A. confusus und H. cf. micronyx leben zwei Tardigradenarten im Schuttsubstrat Huhnerwasser, die eine Reduktion der Krallen aufweisen: der Gattung Apodibius fehlen die Krallen ganzlich, der Gattung Hexapodibius fehlen Krallen am 4. Beinpaar. Die Nutzlichkeit von Krallen im Porensystem grobsandiger Schuttsubstrate und die Notwendigkeit einer Klarung der Position von Apodibius und Hexapodibius im System der Tardigraden werden diskutiert. Derzeit versuchen wir A. confusus in Kultur zu nehmen, um daruber hinaus seine Bewegungsablaufe zu beobachten und Lebenszyklus und Nahrungsspektrum der Art zu untersuchen.

Numerous studies have empirically measured consumer functional responses or theoretically developed response models, but whether these models can quantitatively predict observed data has hardly been tested. We perform such a test for the terrestrial predator–prey system Macrobiotus richtersi (Tardigrada)– Acrobeloides nanus (Nematoda). For two different size classes of A. nanus , we report a functional response as measured in the laboratory and quantitatively compare it to predictions of three models with different degrees of complexity: (1) the disc equation which does not include satiation effects; (2) the steady-state satiation (SSS) equation which assumes a constant level of predator satiation; and (3) the satiation model which accounts for prey depletion and increasing predator satiation over the course of the experiments. We parameterized these models with data that were measured independently of the functional response experiments. In both prey-size classes, the predictions of the satiation model matched the observations best, and the match came close to that of logistic regressions fitted to the observations. Thus, the parameterized satiation model seems to include the most important determinants of the functional response in our focal system. For understanding functional responses, we need more studies that compare data to independently derived model predictions.

Summary In an afforested coal-mining site at Berzdorf, Germany, the soil tardigrade community was investigated. Tardigrade densities ranged from 300 to 33,600 individuals m −2 . Tardigrade distribution was very aggregated with standard deviations of up to 220% of mean densities. Fourteen species belonging to five eutardigrade genera were identified. Soils were dominated by the carnivorous tardigrade Macrobiotus richtersi that contributed 60% of overall densities. A comparison between nine soils of different forest ages (4–46 years) and tree species (poplar, alder, pine, mixed deciduous and mixed coniferous) showed no relationship of tardigrade species distribution and abundance to tree species, thickness of organic or litter layer, humus form, pH or soil moisture. Further, no correlation between nematode biomass and Macrobiotus richtersi abundances were detected. The age of afforested soils, however, affected tardigrade densities: younger soils (7–17 years) yielded higher tardigrade numbers compared to 46-year-old sites. Life history investigations on a strain of parthenogenetic Macrobiotus richtersi demonstrated a significant influence of temperature on egg development, survival rate, body growth and generation time. Hatching, first to fourth molts and maturing, on the other hand, were dependent upon body size alone. The simple, new culture method for carnivorous tardigrades described has successfully been utilized for parthenogenetic Macrobiotus richtersi for 6 years.

Summary Brown-coal opencast mining provides a virgin soil substratum at a scale of square kilometres that is open to primary succession. Focusing on this process, we investigated changes in collembolan species composition in a long-term study that lasted almost 40 years (1960–1998) at mine sites, afforested with deciduous trees. The geological overburden, which characterises the soil quality, consisted mainly of Pleistocene and Tertiary sands, interspersed with lignite and dark Tertiary loam and clay. According to their appearance during the primary succession, we established eight colonising groups, representing 90 of 113 species found. Results from soil samples as well as from pitfall traps were taken into account for the definition of the groups. Thus, edaphic and epedaphic life forms were equally regarded. Generally, “initial”, “pioneer” and “woodland” groups were discernible. Largest changes in species composition occurred during the first ten years, as indicated by decreasing species turnover rates and increasing alpha diversity. A comparison with other (essentially shorter) studies on Collembola of mine sites (12 in Europe, 3 in other parts of the world) showed that some pioneer species are cosmopolitan whilst others seem to be regionally specific. Important events in the ecosystem development of mine sites, as indicated by the collembolan community, are the first occurrence of other humiphagous soil animal groups, especially that of earthworms, followed by a disappearance of the ectohumus layer. The similarity between collembolan communities of mine sites and of adjacent native woodlands is greatest ten years after afforestation. Fifty years after afforestation, the collembolan community still differed markedly from that of native stands. Thus, a gradual development of the mine site collembolan communities to a comparable native woodland community is not evident from the data.

Summary At the afforested overburden heap “Langteichhalde” (lignite mining district Berzdorf, Eastern Germany) a long-term study of the soil fauna (since 1961) was completed by new investigations between 1996–1999 taking microfauna, mesofauna and macrofauna into consideration. Detailed information about the present development of testate amoebae, nematodes, lumbricids, spiders and harvestmen, oribatids, centipedes, millipedes, apterygotes, ants, carabid and staphylinid beetles are briefly compared with the earlier succession of these groups. Generally, both the species inventory as well as diversity points to a change from open landscape communities to woodland associations, albeit in a more or less poor condition. Differences of the settlement depending on deciduous or coniferous afforestation type and surface profile (crests, troughs) are discussed. The contribution of soil organisms to organic matter decomposition was studied by bait lamina tests, the minicontainer technique, and by calculating the potential zootic decomposition level. At the deciduous afforestation the overall soil biological activity reaches the level of natural woodland soils very quickly (after 10– 20 years), even though based upon the continuing development of soil faunal entities. Primarily coniferous afforestations show an impeded decomposing activity, even if developing in a mixed wood. During succession of the mine site community an interesting interrelationship between parts of the soil fauna, especially between lumbricids and microarthropods, can be demonstrated.

According to the current opinion, bisexual tardigrades lay their eggs before pronuclear fusion and partenogenetic tardigrades before cleavage and differentiation. Meiosis (or a corresponding ameiotic oocyte division in many parthenogenetic strains) stops at the first metaphase and starts again after oviposition. Tardigrades, therefore, are considered as being exclusively oviparous (for review see Marcus 1929; Bertolani and Rebecchi 1999; see also Suzuki 2003). When checking a series of permanent preparations enclosed in Faure’s medium made by one of us (K.H.) Dr. H. Dastych, Hamburg, called our attention to a female of Macrobiotus richtersi that obviously carried two embryonated eggs and, thus, differed remarkably from other gravid females of the same population. The specimens of the series came from a long-term culture on agar and were fed with nematodes (see Hohberg, in prep.). During April 1999–December 2003 no males were detected. Juvenile females isolated from others continuously produced young without males when they reached maturity. Therefore, we assume that the population is thelitokous parthenogenetic. In the wild and in culture gravid females reach the remarkable length of up to 860 mm (smallest gravid females measured 450 mm) and carry up to 27 mature oocytes in their ovaries. More than once we observed

We investigated foraging behavior of a carnivorous eutardigrade, Macrobiotus richtersi, living in soil or fresh water sediments, where the distribution of nematode prey is heterogeneous and where, consequently, the value of information about prey availability should be high. We directly observed diet choice in various mixtures of 2 size classes of nematodes Acrobeloides nanus, A1 (small prey) and A2 (large prey), differing in profitability (biomass divided by handling time) but not in digestive quality. At various prey densities of A2, we measured how much of each prey item was consumed as a function of search time. Additionally, we derived cumulative biomass uptake rates per single A2 prey from 154 complete feeding acts, and we used the marginal value theorem (MVT) to predict optimal residence time and prey exploitation as a function of environmental quality and search time. Macrobiotus richtersi did not preferentially select the more profitable size class A2 but increased its biomass uptake rate by modifying the amount consumed per prey item (partial consumption): when encounter rates were high and there were more high-quality prey, the tardigrade abandoned food more quickly and consumed less biomass per captured prey. We conclude that 1) hungry tardigrades under food-rich or food-limited conditions maximize biomass gain according to MVT and 2) tardigrades differentiate at least 2 prey situations, high supply (at high encounter rates) and low supply (at moderate and low prey densities). 3) Partial consumption, performed under food-rich conditions or by a satiated predator, leads to a reduction of prey numbers up to 3 times as much as under food-poor conditions. Copyright 2009, Oxford University Press.

In a series of laboratory experiments, we presented carnivorous Macrobiotus richtersi (Tardigrada, Macrobiotidae) with nematode prey to assess their importance as predator. We investigated consumption rate for (a) different prey densities (10-400 prey individuals), (b) different prey biomasses (22-80 ng), (c) different prey species (Pelodera teres, Rhabditidae, versus Acrobeloides nanus, Cephalobidae) and (d) different environments (2-D agar surface versus 3-D sand fractions of three different textures). M. richtersi consumed up to 4.6 mu g nematode prey in 4 h, that is, 43% of the tardigrade's body mass. Predation rate was positively correlated with prey density. The optimal prey in the present investigation was the biggest prey because it yielded the highest biomass uptake per time. In addition, the size of M. richtersi played an important role in consumption rate. Bacterivorous nematodes reacted differently to attack. Even in a water film on stiff agar where nematode agility was limited, a vigorous undulation reaction of P. teres led to a measurable reduction in consumption rate. A. nanus, in contrast, showed little response to attack. Microcosm experiments with sands of different particle size demonstrated that M. richtersi is able to chase and consume small bacterivorous nematodes in a 3-D soil matrix. However, consumption rate in sand microcosms was significantly reduced compared with pure agar. The sand matrix improved nematode agility and possibly provided small pores as refuge for the nematodes. The lowest consumption rate was observed in fine sand. Effects of predatory tardigrades on nematode numbers in the field are discussed.

Background: Although molecular analyses have contributed to a better resolution of the animal tree of life, the phylogenetic position of tardigrades (water bears) is still controversial, as they have been united alternatively with nematodes, arthropods, onychophorans (velvet worms), or onychophorans plus arthropods. Depending on the hypothesis favoured, segmental ganglia in tardigrades and arthropods might either have evolved independently, or they might well be homologous, suggesting that they were either lost in onychophorans or are a synapomorphy of tardigrades and arthropods. To evaluate these alternatives, we analysed the organisation of the nervous system in three tardigrade species using antisera directed against tyrosinated and acetylated tubulin, the amine transmitter serotonin, and the invertebrate neuropeptides FMRFamide, allatostatin and perisulfakinin. In addition, we performed retrograde staining of nerves in the onychophoran Euperipatoides rowelli in order to compare the serial locations of motor neurons within the nervous system relative to the appendages they serve in arthropods, tardigrades and onychophorans. Results: Contrary to a previous report from a Macrobiotus species, our immunocytochemical and electron microscopic data revealed contralateral fibres and bundles of neurites in each trunk ganglion of three tardigrade species, including Macrobiotus cf. harmsworthi, Paramacrobiotus richtersi and Hypsibius dujardini. Moreover, we identified additional, extra-ganglionic commissures in the interpedal regions bridging the paired longitudinal connectives. Within the ganglia we found serially repeated sets of serotonin- and RFamid-like immunoreactive neurons. Furthermore, our data show that the trunk ganglia of tardigrades, which include the somata of motor neurons, are shifted anteriorly with respect to each corresponding leg pair, whereas no such shift is evident in the arrangement of motor neurons in the onychophoran nerve cords. Conclusions: Taken together, these data reveal three major correspondences between the segmental ganglia of tardigrades and arthropods, including (i) contralateral projections and commissures in each ganglion, (ii) segmentally repeated sets of immunoreactive neurons, and (iii) an anteriorly shifted (parasegmental) position of ganglia. These correspondences support the homology of segmental ganglia in tardigrades and arthropods, suggesting that these structures were either lost in Onychophora or, alternatively, evolved in the tardigrade/arthropod lineage.