Trench-parallel anisotropy produced by foundering of arc lower crust

Many volcanic arcs display fast seismic shear-wave velocities parallel to the strike of the trench. This pattern of anisotropy is inconsistent with simple models of corner flow in the mantle wedge. Although several models, including slab rollback, oblique subduction, and deformation of water-rich olivine, have been proposed to explain trench-parallel anisotropy, none of these mechanisms are consistent with all observations. Instead, small-scale convection driven by the foundering of dense arc lower crust provides an explanation for the trench-parallel anisotropy, even in settings with orthogonal convergence and no slab rollback.     

Landscape and habitat filters jointly drive richness and abundance of specialist plants in terrestrial habitat islands

Context

Landscape and habitat filters are major drivers of biodiversity of small habitat islands by influencing dispersal and extinction events in plant metapopulations.

Objectives

We assessed the effects of landscape and habitat filters on the species richness, abundance and trait composition of grassland specialist and generalist plants in small habitat islands. We studied traits related to functional spatial connectivity (dispersal ability by wind and animals) and temporal connectivity (clonality and seed bank persistence) using model selection.

Methods

We sampled herbaceous plants, landscape (local and regional isolation) and habitat filters (inclination, woody encroachment and disturbance) in 82 grassland islands in Hungary.

Results

Isolation decreased the abundance of good disperser specialist plants due to the lack of directional vectors transferring seeds between suitable habitat patches. Clonality was an effective strategy, but persistent seed bank did not support the survival of specialist plants in isolated habitats. Generalist plants were unaffected by landscape filters due to their wide habitat breadth and high propagule availability. Clonal specialist plants could cope with increasing woody encroachment due to their high resistance against environmental changes; however, they could not cope with intensive disturbance. Steep slopes providing environmental heterogeneity had an overall positive effect on species richness.

Conclusions

Specialist plants were influenced by the interplay of landscape filters influencing their abundance and habitat filters affecting species richness. Landscape filtering by isolation influenced the abundance of specialist plants by regulating seed dispersal. Habitat filters sorted species that could establish and persist at a site by influencing microsite availability and quality.

     

Health screening of free-ranging European brown hares (Lepus europaeus) on the German North-Sea island Pellworm

Background

A sudden decline of the European brown hare (Lepus europaeus) population in one of the best hunting districts for small game species in northern Germany, the German North-Sea island Pellworm, in the years 2007/08 following marked habitat changes led to the implementation of a thorough health assessment program of the population. 110 animals were collected during the normal hunting season in the years 2010 and 2011. A post-mortem examination and histopathological investigation was performed on all animals. Additionally, routine bacteriology of the small intestine and parasitology were carried out. Sera of hares were tested for European Brown Hare Syndrome (EBHS) by enzyme linked immunosorbent assay, and for Treponema sp. by indirect immunofluorescent test. Additional testing was performed when deemed necessary.

Results

The most striking result was a shift in the intestinal bacterial flora towards Gram-negative Enterobacteriaceae with a predominance of either Escherichia coli, or Aeromonas sp., or a high-grade double-infection with these two pathogens with subsequent catarrhal enteritis. Additionally, a marked coccidiosis, and varying infestations with the nematode Trichostrongylus retortaeformis were found. The sero-prevalence for EBHS was 78.1%, and for Treponema 43.9%.

Conclusions

The shift and decrease in diversity of the intestinal flora was the main and most consistent result found. In the authors’ opinion the change of the habitat combined with other stressors increased the animals’ sensitivity to ubiquitous bacterial species and parasites which usually would not have such fatal effects.     

Effect of different fibre types on the digestibility of nutrients in cats

In this study the effect of different fibre types was investigated on the acceptance of foods (in a short-term study) and on the nutrients' digestibility by using 10 adult, castrated cats. Peanut hull (PH, source of lignin), dried sugar beet pulp (SBP, source of hemicelluloses and pectin) and alfalfa meal (ALF, source of cellulose) were mixed to a poultry meat based cat food in 10% on dry matter (DM) basis. The average DM intake did only slightly differ according to the type of fibre added. Supplementation of basal food by dried SBP did not influence the digestibility of DM and crude protein (CP) significantly. Using ALF as a fibre source decreased the digestibility of DM (85.8% vs. 78.6%) and CP (93.8% vs. 92.0%) significantly. More severe decline could be observed in the digestibility of DM (85.8% vs. 63.4%) and CP (93.8% vs. 83.7%) when using PH as a fibre source. Fibre sources also influenced the stool DM content significantly. While application of PH increased the DM content of the faeces (45.0% vs. 49.6%), the use of dried sugar beet or ALF reduced the faecal DM content (45.0% vs. 24.1% and 39.0%, respectively). According to these results the less digestible fibre source (PH) increased the DM content of the faeces while by improving the digestibility of the fibre sources the DM content of the faeces decreased. It can be concluded, that not only the absolute fibre content of the food but also the type of fibre must be taken into account when evaluating its possible role as a component of weight loss products.     

Systemic Granulomatous Disease in a Hungarian Warmblood Gelding

An 8-year-old Hungarian warmblood gelding used for show jumping was evaluated because of poor performance and chronic weight loss. On admission, oral and gastroesophageal ulcerations and malabsorption were detected. Results of thoracic radiography, ultrasonography, bronchoalveolar lavage cytology, and positive polymerase chain reaction for equine herpesvirus 5 raised the possible diagnosis of equine multinodular pulmonary fibrosis. However, abdominal ultrasonography revealed inhomogeneous spleen with many different sized well-demarcated hypoechoic areas, which suggested further differential diagnoses such as tuberculosis, neoplasias, immune mediated diseases, systemic granulomatous disease (SGD), or toxicoses. The horse was euthanized at the owner's request because of the poor condition and possible grave prognosis. Histopathology findings were characteristic of SGD, which is a rare disorder of horses characterized by skin lesions, weight loss, and granulomatous inflammation of multiple organ systems. The lack of skin lesions in this case is an unusual finding. Systemic granulomatous disease is hypothesized to be induced by multiple conventional antigens that are not cleared from affected tissues. Equine herpesvirus 5 might have triggered the granulomatous reactions in this particular case.     

LGI Proteins and Epilepsy in Human and Animals

Leucine‐rich glioma‐inactivated (LGI) protein was first thought to have a suppressor effect in the formation of some cancers. Developments in physiology and medicine made it possible to characterize the function of the LGI protein family and its crucial role in different conditions more precisely. These proteins play an important role in synaptic transmission, and dysfunction may cause hyperexcitability. Genetic mutation of LGI1was confirmed to be the cause of autosomal dominant lateral temporal lobe epilepsy in humans. The LGI2 mutation was identified in benign familial juvenile epilepsy in Lagotto Romagnolo (LR) dogs. Cats with familial spontaneous temporal lobe epilepsy have been reported, and the etiology might be associated with LGI protein family dysfunction. In addition, an autoimmune reaction against LGI1 was detected in humans and cats with limbic encephalitis. These advances prompted a review of LGI protein function and its role in different seizure disorders.     

Resistance to neonicotinoid insecticides in field populations of the Colorado potato beetle (Coleoptera: Chrysomelidae)

BACKGROUND: Neonicotinoid insecticides were first used commercially for Colorado potato beetle [Leptinotarsa decemlineata (Say), Coleoptera: Chrysomelidae] control in the United States in 1995, and since then have been critical for management of this pest. Field populations from the northeastern and midwestern United States were tested from 1998 to 2010 for susceptibility to imidacloprid and thiamethoxam using standard topical dose assays with adults. RESULTS: From 1998 to 2001, imidacloprid resistance was present in only a few locations in the eastern United States. By 2003, imidacloprid resistance was common in the northeastern Unites States. In 2004, imidacloprid resistance in Colorado potato beetle was detected for the first time in the midwestern United States. In 2003, the first case of resistance to thiamethoxam was found in a population from Massachusetts. Neonicotinoid resistance in summer‐generation adults was higher than in overwintered adults from the same locations. By 2009, 95% of the populations tested from the northeastern and midwestern United States had significantly higher LD₅₀ values for imidacloprid than the susceptible population. CONCLUSIONS: The increasing resistance to neonicotinoid insecticides raises concerns for the continued effective management of Colorado potato beetles in potatoes and highlights the need for more rigorous practice of integrated pest management methods. Copyright © 2011 Society of Chemical Industry