Dispersal of two moderately venomous spiders Cheiracanthium mildei and C. punctorium in Saxony and Brandenburg (Araneae: Miturgidae)

In the summers of 2006 and 2007 presumed bites of Cheiracanthium spiders triggered mass hysteria in Austria and some regions of Germany, including northern Saxonia. Here we report the first records of Cheiracanthium mildei L. Koch, 1864 from Saxony and new records of C. punctorium (Villers, 1789) from Saxony and Brandenburg. C. punctorium is probably a native species in southern Germany. It shows a moderate area expansion that could be driven by global warming. Further records in north-western Saxony are to be expected. By contrast, C. mildei has to be regarded an invasive alien species that has rapidly spread into Central Europe from the Mediterranean. Leipzig is the north-easternmost locality in Europe reached so far, a further 230 km away from Nuremberg, the leading edge in 2006. A number of records in different districts of Leipzig suggest that the species is already established in the town. We also report verified bites of both species. The mild to moderate symptoms are in accordance with recent literature reviews

Sodium 2-mercaptoethanesulfonate monohydrate (coenzyme M sodium salt monohydrate)

The 2-thio­ethanesulfonate anion is the smallest known coenzyme in nature (HS–CoM) and plays a key role in methano­genesis by anaerobic archaea, as well as in the oxidation of alkenes by Gram-negative and Gram-positive eubacteria. The title compound, Na+·C2H5O3S2 −·H2O, is the Na+ salt of HS–CoM crystallized as the monohydrate. Six O atoms form a distorted octa­hedral coordination geometry around the Na atom, at distances in the range 2.312 (4)–2.517 (3) Å. Two O atoms of the sulfonate group, one O atom of each of three other symmetry-related sulfonate groups plus the water O atom form the coordination environment of the Na+ ion. This arrangement forms Na–O–Na layers in the crystal structure, parallel to (100)

Plant diversity and community history shift colonization success from early- to mid-successional species

Aims Functional traits are supposed to play an important role in determining the colonization success of new species into established communities. Short-term experimental studies have documented higher resistance of more diverse grasslands against colonization by new species. However, little is known about which traits colonizers should have to successfully invade diverse plant communities in the longer term and how community history may modify the resistance of diverse communities against colonization. Methods In a grassland biodiversity experiment (Jena Experiment) established with different species richness (SR; 1, 2, 4, 8 and 16) and functional group (FG) number and composition (1 to 4; legumes, grasses, small herbs, tall herbs), we studied colonization of naturally dispersed species in split-plots (i) with different duration of weeding (never weeded, weeded for 3 or 6 years and then un-weeded for 1 year) and (ii) with different duration of colonization (7 years, 4 years and 1 year after cessation of weeding). Important Findings Resistance against colonization by new species declined with increased duration of weeding (on average 13, 17 and 22 colonizer species in 1-, 4- and 7-year-old communities, respectively). Communities established at low diversity accumulated more colonizer species with a longer duration of weeding than more diverse communities. Duration of colonization had only small effects on the number of colonizer species. Colonizers with early successional traits, i.e. annual life cycle, reproduction by seeds, small seeds, long-lived seeds and an earlier start of a longer flowering period, were favoured in species-poor newly established experimental plant communities (short duration of weeding) and early after cessation of weeding (short duration of colonization). A change from early- to mid-successional traits, i.e. taller growth, perennial life cycle, vegetative reproduction, characterized colonization at increased plant diversity and in communities with legumes or without grasses. Legume absence/grass presence and increased duration of weeding led to a shift in colonizer strategies from rapid nutrient uptake and cycling (higher specific leaf area) to nutrient retention and symbiotic N2 fixation. Our study shows that non-random trait spectra of naturally dispersed colonizers encompass trade-offs between different functions (reproduction, persistence, growth) reflected in a change from early- to mid-successional traits at increasing plant diversity, with a longer duration of weeding and a longer time of colonizatio

THE H3/H4 HISTONE GENE CLUSTER OF LAND SNAILS (GASTROPODA: STYLOMMATOPHORA): TS/TV RATIO, GC3 DRIVE AND SIGNALS IN STYLOMMATOPHORAN PHYLOGENY

Histone gene primers were developed for land snails (Stylommatophora). The partial H3/H4 histone gene cluster was cloned and sequenced for 18 species. Transcription of the H3 and H4 genes was divergent (each gene is transcribed in the opposite direction) as has been found for other protostome and diploblast animals, with the exception of Mytilus. In the bivalve Mytilus transcription of both genes occurs in the same direction, i.e. land snails and bivalves seem to differ in their histone gene organization. The non-transcribed H3/H4 spacer varied in length between 279 and 691 basepairs. Nucleotide polymorphisms in this non-transcribed spacer might be of significance to study phylogenetics and systematics of closely related species and genera. As expected, the coding regions exhibited no amino acid substitution among land snail species. However, one amino acid substitution was found in comparison between land snails and Drosophila. The transition/transversion (TS/TV) ratio of H3 and H4 was predominately shaped by the third codon position and ranged in most cases from 1.0 to 2.0, indicating low nucleotide saturation. GC content was calculated for the third codon position (GC3 index at the ‘wobble' base position). The histone GC3 values were far lower in land snails than values currently available for other genomes (i.e. mammals). This indicates that H3/H4 histone wobble bases of land snails evolve without strong GC drive. Phylogenetic trees were reconstructed from the coding regions. We used Succinea putris (Elasmognatha) as outgroup. Trichia villosa (Helicoidea) showed six apomorphic nucleotide signals. Moreover, the nucleotide signals give evidence that the Cochlicopidae, Vertiginidae and Valloniidae are paraphyletic family categories. The paraphyletic status of cochlicopid, vertiginid and valloniid gastropods is also supported by our unpublished ribosomal DNA tree

Wolbachia distribution in selected beetle taxa characterized by PCR screens and MLST data

Wolbachia (Alphaproteobacteria) is an inherited endosymbiont of arthropods and filarial nematodes and was reported to be widespread across insect taxa. While Wolbachia’s effects on host biology are not understood from most of these hosts, known Wolbachia-induced phenotypes cover a spectrum from obligate beneficial mutualism to reproductive manipulations and pathogenicity. Interestingly, data on Wolbachia within the most species-rich order of arthropods, the Coleoptera (beetles), are scarce. Therefore, we screened 128 species from seven beetle families (Buprestidae, Hydraenidae, Dytiscidae, Hydrophilidae, Gyrinidae, Haliplidae, and Noteridae) for the presence of Wolbachia. Our data show that, contrary to previous estimations, Wolbachia frequencies in beetles (31% overall) are comparable to the ones in other insects. In addition, we used Wolbachia MLST data and host phylogeny to explore the evolutionary history of Wolbachia strains from Hydraenidae, an aquatic lineage of beetles. Our data suggest that Wolbachia from Hydraenidae might be largely host genus specific and that Wolbachia strain phylogeny is not independent to that of its hosts. As this contrasts with most terrestrial Wolbachia–arthropod systems, one potential conclusion is that aquatic lifestyle of hosts may result in Wolbachia distribution patterns distinct from those of terrestrial hosts. Our data thus provide both insights into Wolbachia distribution among beetles in general and a first glimpse of Wolbachia distribution patterns among aquatic host lineages

Differential effects of plant diversity on functional trait variation of grass species

Background and Aims Functional trait differences and trait adjustment in response to influences of the biotic environment could reflect niche partitioning among species. In this study, we tested how variation in above-ground plant traits, chosen as indicators for light and nitrogen acquisition and use, differs among taxonomically closely related species (Poaceae) to assess their potential for niche segregation at increasing plant diversity. Methods Traits of 12 grass species were measured in experimental grasslands (Jena Experiment) of varying species richness (from 1 to 60) and presence of particular functional groups (grasses, legumes, tall herbs and small herbs). Key Results Grass species increased shoot and leaf length, investment into supporting tissue (stem mass fraction) and specific leaf area as well as reduced foliar δ13C values with increasing species richness, indicating higher efforts for light acquisition. These species-richness effects could in part be explained by a higher probability of legume presence in more diverse communities. Leaf nitrogen concentrations increased and biomas s : N ratios in shoots decreased when grasses grew with legumes, indicating an improved nitrogen nutrition. Foliar δ15N values of grasses decreased when growing with legumes suggesting the use of depleted legume-derived N, while decreasing δ15N values with increasing species richness indicated a shift in the uptake of different N sources. However, efforts to optimize light and nitrogen acquisition by plastic adjustment of traits in response to species richness and legume presence, varied significantly among grass species. It was possible to show further that trait adjustment of grass species increased niche segregation in more diverse plant communities but that complementarity through niche separation may differ between light and nutrient acquisition. Conclusions The results suggest that even among closely related species such as grasses different strategies are used to cope with neighbours. This lack in redundancy in turn may facilitate complementary resource use and coexistenc