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Knillmann S.,Helmholtz Center for Environmental Research | Knillmann S.,RWTH Aachen | Stampfli N.C.,Helmholtz Center for Environmental Research | Stampfli N.C.,University of Koblenz-Landau | And 3 more authors.
Ecotoxicology | Year: 2012

Xenobiotics alter the balance of competition between species and induce shifts in community composition. However, little is known about how these alterations affect the recovery of sensitive taxa. We exposed zooplankton communities to esfenvalerate (0.03, 0.3, and 3 μg/L) in outdoor microcosms and investigated the longterm effects on populations of Daphnia spp. To cover a broad and realistic range of environmental conditions, we established 96 microcosms with different treatments of shading and periodic harvesting. Populations of Daphnia spp. decreased in abundance for more than 8 weeks after contamination at 0.3 and 3 μg/L esfenvalerate. The period required for recovery at 0.3 and 3 μg/L was more than eight and three times longer, respectively, than the recovery period that was predicted on the basis of the life cycle of Daphnia spp. without considering the environmental context. We found that the recovery of sensitive Daphnia spp. populations depended on the initial pesticide survival and the related increase of less sensitive, competing taxa. We assert that this increase in the abundance of competing species, as well as sub-lethal effects of esfenvalerate, caused the unexpectedly prolonged effects of esfenvalerate on populations of Daphnia spp. We conclude that assessing biotic interactions is essential to understand and hence predict the effects and recovery from toxicant stress in communities. © Springer Science+Business Media, LLC 2012. Source


Knillmann S.,Helmholtz Center for Environmental Research | Knillmann S.,RWTH Aachen | Stampfli N.C.,Helmholtz Center for Environmental Research | Stampfli N.C.,University of Koblenz-Landau | And 3 more authors.
Global Change Biology | Year: 2013

Considerable research efforts have been made to predict the influences of climate change on species composition in biological communities. However, little is known about how changing environmental conditions and anthropogenic pollution can affect aquatic communities in combination. We investigated the influence of short warming periods on the response of a zooplankton community to the insecticide esfenvalerate at a range of environmentally realistic concentrations (0.03, 0.3 and 3 μg L-1) in 55 outdoor pond microcosms. Warming periods increased the cumulative water temperature, but did not exceed the maximum temperature measured under ambient conditions. Under warming conditions alone the abundance of some zooplankton taxa increased selectively compared to ambient conditions. This resulted in a shift in the community composition that had not recovered by the end of the experiment, 8 weeks after the last warming period. Regarding the pesticide exposure, short-term effects of esfenvalerate on the community structure and the sensitive taxa Daphnia spp. did not differ between the two temperature regimes. In contrast, long-term effects of esfenvalerate on Daphnia spp., a taxon that did not benefit from elevated temperatures, were observed twice as long under warming than under ambient conditions. This resulted in long-term effects on Daphnia spp. until 4 months after contamination at 3 μg L-1 esfenvalerate. Under both temperature regimes, we identified strength of interspecific competition as the mechanism determining the time until recovery. However, enhanced interspecific competition under warming conditions was prolonged and explained the delayed recovery of Daphnia spp. from esfenvalerate. These results show that, for realistic prediction of the combined effects of changing environmental factors and toxicants on sensitive taxa, the impacts of stressors on the biotic interactions within the community need to be considered. © 2013 Blackwell Publishing Ltd. Source


Malysh J.M.,All Russian Institute of Plant Protection | Tokarev Y.S.,All Russian Institute of Plant Protection | Martemyanov V.V.,Institute of Systematics and Ecology of Animals | Frolov A.N.,All Russian Institute of Plant Protection | Issi I.V.,All Russian Institute of Plant Protection
Acta Protozoologica | Year: 2013

Adults of beet webworm Loxostege sticticalis were collected in Western Siberia in 2009 and 2010. A microsporidium was found infecting 12 of 50 moths in 2010. The parasite develops in direct contact with host cell cytoplasm, sporogony is presumably disporoblastic. The spores are ovoid, diplokaryotic, 4.2 × 2.4 μm in size (fresh), without a sporophorous vesicle. Electron microscopy showed: (a) tubules on the surface of sporoblasts and immature spores; (b) slightly anisofilar polar tube with 10-14 coils, last 2-3 coils of lesser electron density; (c) bipartite polaroplast with anterior and posterior parts composed of thin and thick lamellae, respectively; (d) an indentation in the region of the anchoring disc; (e) an additional layer of electron-dense amorphous matter on the exospore surface. The spore ultrastructure is characteristic of the genus Tubulinosema. Sequencing of small subunit and large subunit ribosomal RNA genes showed 98-99.6% similarity of this parasite to the Tubulinosema species available on Genbank. A new species Tubulinosema loxostegi sp. n. is established. Source


Pachyseius anisimovi sp. nov. is described based on specimens from soil and litter in the Altai Mountains and the West and East Sayan Mountains in South Siberia, Russia. A key to ten Pachyseius species known from Asia is provided. Copyright © 2015 Magnolia Press. Source


Arai S.,Japan National Institute of Infectious Diseases | Kang H.J.,University of Hawaii at Manoa | Gu S.H.,University of Hawaii at Manoa | Ohdachi S.D.,Hokkaido University | And 8 more authors.
Vector-Borne and Zoonotic Diseases | Year: 2016

Although based on very limited M and L segment sequences, Artybash virus (ARTV) was proposed previously as a unique hantavirus harbored by the Laxmann's shrew (Sorex caecutiens). To verify this conjecture, lung tissues from 68 Laxmann's shrews, captured during 2006 to 2014 in eastern Siberia, Russia, and Hokkaido, Japan, were analyzed for ARTV RNA using reverse transcription polymerase chain reaction (RT-PCR). ARTV RNA was detected in six Laxmann's shrews. Pairwise alignment and comparison of partial- and full-length S, M, and L segment sequences from these Laxmann's shrews, as well as phylogenetic analyses, using maximum likelihood and Bayesian methods indicated that ARTV was distinct from other soricine shrew-borne hantaviruses and representative hantaviruses harbored by rodents, moles, and bats. Taxonomic identity of the ARTV-infected Laxmann's shrews was confirmed by full-length cytochrome b mitochondrial DNA sequence analysis. Our data indicate that the hantavirus previously known as Amga virus (MGAV) represents genetic variants of ARTV. Thus, the previously proposed designation of ARTV/MGAV should be replaced by ARTV. © Copyright 2016, Mary Ann Liebert, Inc. 2016. Source

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