Highest degrees of host specificity even in the inundative biocontrol approach : response to Cripps et al.

Volume: 13Start Page: 41End Page: 4

Taxonomic note on Aculepeira lapponica (Arachnida: Araneae: Araneidae)

Caused by the similarity with the type species Aculepeira packardi and with A. ceropegia we confirm the combination Aculepeira lapponica for the arctic araneid Aranea lapponica Holm, 1945

Plant pathogens as biocontrol agents of Cirsium arvense : an overestimated approach?

Cirsium arvense is one of the worst weeds in agriculture. As herbicides are not very effective and not accepted by organic farming and special habitats, possible biocontrol agents have been investigated since many decades. In particular plant pathogens of C. arvense have received considerable interest and have been promoted as “mycoherbicides” or “bioherbicides”. A total of 10 fungi and one bacterium have been proposed and tested as biocontrol agents against C. arvense. A variety of experiments analysed the noxious influence of spores or other parts of living fungi or bacteria on plants while others used fungal or bacterial products, usually toxins. Also combinations of spores with herbicides and combinations of several pathogens were tested. All approaches turned out to be inappropriate with regard to target plant specificity, effectiveness and application possibilities. As yet, none of the tested species or substances has achieved marketability, despite two patents on the use of Septoria cirsii and Phomopsis cirsii. We conclude that the potential of pathogens for biocontrol of C. arvense has largely been overestimated

Kuschka V. (2004): Ackerbrachen als Chance für den Naturschutz? Struktur und Dynamik von Spinnenzönosen der Bodenoberfläche als Indikator der Habitatqualität

Buchbesprechun

Introduction, establishment rate, pathways and impact of spiders alien to Europe

A comprehensive analysis of spiders reported as alien for Europe over the last 200 years has yielded information for 184 spider species, which had been introduced at least once. The most common spider families are Theridiidae (27 species), Pholcidae (15), Salticidae (14), Sparassidae (14), Ctenidae (14), and Theraphosidae (13) but overall establishment rate was only 28 %. No ctenids or theraphosids established, and only one sparassid species, but many theridiids and pholcids. Most introduced species originated from South (34 %), Central (10 %) or North (12 %), America, Asia (19 %) and Africa (15 %). Only few of the South and Central American species could establish, while species from North America (36 %) and Asia (63 %) had much higher establishment rates. Over the last 200 years, introduction and establishment rates have been strongly increasing. Three pathways are responsible for the majority of introductions: fruit shipments (67 % of all cases), potted plants (16 %) and containers or packaging material (12 %). In contrast to fruit shipments, spiders introduced on plants or with containers have high establishment rates (65 and 47 %). Environmental impact of alien spiders can be expected on both insects (through predation) and spiders (through predation and competition), potentially leading to change of species composition and guild structure. Socio-economic impact includes reduction of marketability of horticultural products through excessive spinning activity which also may cause increased cleaning costs at facades and windows. Impact on human health may be caused by bites and subsequent need for medical treatments. For all these impact categories, however, only anecdotal evidence is given for alien spiders in Europe. This may change when spiders of medical importance such as the frequently introduced Latrodectus species will establish. Considering the current trends it is concluded that introduction and establishment rates of alien spiders will strongly increase in the next years unless preventive methods become more efficient

Ingestion and excretion of two transgenic Bt corn varieties by slugs

The release of transgenic Bacillus thuringiensis (Bt) corn expressing various Cry endotoxins has raised concern that these endotoxins are disseminated in the food web and may adversely affect non-target beneficial organisms, such as predators and organisms of the decomposer food web. We therefore investigated in a laboratory study, whether the Cry1Ab and Cry3Bb1 protein from Bt corn could potentially be transferred to such organisms by measuring the Cry protein content in the two common agricultural slug pests Arion lusitanicus and Deroceras reticulatum and their feces. We measured Cry1Ab and Cry3Bb1 protein concentration in leaves, intestines, and feces of corn leaf-fed slugs using ELISA and determined how much of the ingested protein is excreted by the slugs. Cry3Bb1 concentration in leaves of DKC5143Bt corn was significantly higher than Cry1Ab concentration in leaves of N4640Bt corn. While slugs were feeding on corn leaves, the Cry3Bb1 and Cry1Ab proteins were found in intestines and feces of both slug species. Bt protein concentrations in intestines of Cry3Bb1 corn-fed slugs were in both slug species higher than in Cry1Ab corn fed slugs, whereas no differences between Cry3Bb1 and Cry1Ab protein in feces were found. After slugs had ceased feeding on Bt corn, Cry1Ab was detectable in fresh slug feces for a significantly longer time and often in higher amounts than the Cry3Bb1. Our results indicate that both Cry proteins are likely to be transferred to higher trophic levels and to the decomposer food web. Since different Bt proteins seem to vary in their degradation, they have different transfer probabilities. This should be considered in risk assessments for non-target arthropod

Expression of defensins in non-infected araneomorph spiders

Defensins are a major family of antimicrobial peptides found throughout the phylogenetic tree. From the spider species: Cupiennius salei, Phoneutria reidyi, Polybetes pythagoricus, Tegenaria atrica, and Meta menardi, defensins belonging to the ‘ancestral' class of invertebrate defensins were cloned and sequenced. The deduced amino acid sequences contain the characteristic six cysteines of this class of defensins and reveal precursors of 60 or 61 amino acid residues. The mature peptides consist of 37 amino acid residues, showing up to 70% identities with tick and scorpion defensins. In C. salei, defensin mRNA was found to be constitutively expressed in hemocytes, ovaries, subesophageal nerve mass, hepatopancreas, and muscle tissue. This is the first report presenting and comparing antimicrobial peptides belonging to the family of defensins from spider

Progress in erigonine spider phylogeny—the Savignia -group is not monophyletic (Araneae: Linyphiidae)

We present the most inclusive study on the higher-level phylogeny of erigonine spiders, including about 30% of all erigonine genera. By expanding the previously most comprehensive analysis (Miller and Hormiga Cladistics 20:385-442, 2004) we tested the robustness of its results to the addition of closely related taxa, and also the monophyly of the Savignia-group defined by Millidge (Bulletin of the British Arachnological Society 4:1-60, 1977). The character matrix was expanded by adding 18 newly scored species in 15 genera, and also includes all species scored by other authors. This adds up to 98 species in 91 erigonine genera plus 13 outgroup taxa. The parsimony analysis led to eight fully resolved most parsimonious trees (L=1084). The topology concerning the taxa basal to the ‘distal erigonines' remained unchanged, and the latter clade still shares 67% of all nodes with the original analysis. The Savignia-group is not monophyletic at genus level with respect to Saloca diceros and Alioranus pastoralis, and the same applies at species level in Diplocephalus and Erigonella. From the Savignia-group, Glyphesis servulus, Diplocephalus cristatus, Savignia frontata, and two representatives each of Erigonella, Dicymbium and Araeoncus combine to form a monophyletic clad

Spider (Arachnida: Araneae) distribution across the timberline in the Swiss Central Alps (Alp Flix, Grisons) and three morphologically remarkable species

We collected 6251 adult epigeic spiders from the dwarf-shrub heath to subalpine coniferous forest on Alp Flix (CH, canton Grisons, 1950 m) between May 2005 and May 2006 using pitfall traps. Total species richness and activity density of all species decreased from the open land to the forest, although this pattern varied according to family. The distribution of the 102 species found indicates that the small area around a single tree at the timberline provides habitats for both open land and forest spider species as well as some possible timberline specialists. Five species were new to the canton Grisons: Centromerita bicolor, Centromerita concinna, Hilaira excisa, Meioneta alpica and Tallusia experta. Three species showed remarkable morphological characteristics and were analysed in more detail. We found males of Pelecopsis radicicola without the characteristic longitudinal depression on the raised carapace. It is shown that the males of Meioneta alpica have a considerably variable lamella characteristica, which is nevertheless distinct from the sister species Meioneta ressli. Because we found intermediate forms of the head region described for Metopobactrus prominulus and M. schenkeli, respectively, M. schenkeli is considered a syn. nov. of M. prominulus. This study shows that the known distribution and taxonomic status of various spider taxa in the Central Alps are still incomplete and further work on arthropods in remote areas should be strongly encouraged