Overige insecten

In this study, we exposed red imported fire ants, Solenopsis invicta Buren, to sublethal dosages of dietary imidacloprid and investigated its effect on ant feeding, digging, and foraging behavior. S. invicta consumed significantly more sugar water containing 0.01 microgram/ml imidacloprid than untreated sugar water. Ants fed with 0.01 microgram/ml imidacloprid also showed significantly increased digging activity than ants fed with untreated sugar water. However, imidacloprid at 0.25 microgram/ml significantly suppressed sugar water consumption, digging, and foraging behavior. These results indicate that imidacloprid at sublethal concentrations may have a significant and complicated effect on S. invicta.

Toxoneuron nigriceps (Viereck) (Hymenoptera, Braconidae) and Campoletis sonorensis (Cameron) (Hymenoptera, Ichneumonidae) are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera, Noctuidae). They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011–2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches.

On an independent modern farm followed by certified veterinarians, dairy cows (mean of 62 per year) were maintained in optimized milk production for 3 years each. From 1997 to 2002, just after the commercial release of the first GMO (genetically modified organism) in Europe, genetically modified (GM) Bt176 maize grown on the farm was progressively introduced in controlled diets. The results are described in the following account, which has an historical value as it is the longest and first on-farm observation of mammals, performed by an experienced farmer and veterinarians, during a period of unusual pathological problems in cows receiving a GMO-rich diet. Thus it was not designed as a scientific experiment. Over the years, and coinciding with regular increases in GMO content of the diet (0–40%), the proportion of healthy cows with high milk yield diminished from 70% (normal rate) to only 40%. At the peak of mortalities in 2002, 10% of the cows died, preceded by a long-lasting paresis syndrome without hypocalcemia or fever, but with kidney biochemical failure and mucosa or epithelial problems. No microbial origin was identified, though intensively investigated. The GM maize, subsequently withdrawn from the market, was at the time the only intended managerial change for the cows. It is proposed that it provoked long-term toxic effects on mammals, which are not observable in most common conditions of intensive farming with high and rapid animal turnover and with no specific labels on GM feed (identifying amount and precise identity of GMO content). More long-term assessments during GMO feeding trials should be performed.

Reports of bat deaths worldwide due to human causes largely unique to the 21st century are markedly rising, according to a new USGS-led analysis published in Mammal Review. Collisions with wind turbines worldwide and the disease white-nose syndrome in North America lead the reported causes of mass death in bats since the onset of the 21st century. These new threats now surpass all prior known causes of bat mortality, natural or attributed to humans. A comprehensive study reveals trends in the occurrence and causes of multiple mortality events in bats as reported globally for the past 200 years, shedding new light on the possible factors underlying population declines. "Many of the 1,300 species of bats on Earth are already considered threatened or declining. Bats require high survival to ensure stable or growing populations," said Tom O'Shea, a USGS emeritus research scientist and the study's lead author. "The new trends in reported human-related mortality may not be sustainable."

Mayfly nymphs are among the most sensitive taxa to neonicotinoids. The present study presents the acute and chronic toxicity of 3 neonicotinoids (imidacloprid, thiacloprid, and thiamethoxam) to a mayfly species (Cloeon dipterum) and some notes on the seasonality of the toxicity of imidacloprid to C. dipterum and 5 other invertebrate species. Imidacloprid and thiamethoxam showed equal acute and chronic toxicity to a winter generation of C. dipterum, whereas thiacloprid was approximately twice as toxic. The acute and chronic toxicity of imidacloprid was much higher for the C. dipterum summer generation than for the winter one. The acute toxicity differs by a factor of 20 for the 96-h 50% effective concentration (EC50) and by a factor of 5.4 for the chronic 28-d EC50. Temperature had only a slight effect on the sensitivity of C. dipterum to imidacloprid because we only found a factor of 1.7 difference in the 96-h EC50 between tests performed at 10 8C and 18 8C. The difference in sensitivity between summer and overwintering generations was also found for 3 other insect species. The results indicate that if the use and environmental fate of the 3 neonicotinoids are comparable, replacing imidacloprid by another neonicotinoid might not reduce the environmental impact on the mayfly nymph C. dipterum. The results also show the importance of reporting which generation is tested because sensitivity values of insects in the summer might be underestimated by the experiments performed with neonicotinoids and an overwintering population.

Der Imkerverein Lingen hat bei seiner Generalversammlung verdiente Imker ausgezeichnet. Darüber hinaus zeigten sich die Imker besorgt über die Auswirkungen der Veränderungen der Landschaft auf die Imkerei. Den Beobachtungen der Imker zufolge nimmt seit den 1950er Jahren die Zahl der Hummeln, Wildbienen und Schmetterlinge dramatisch ab. Das zeige, dass unsere Landschaft sich dramatisch verändert habe, heißt es in einer Pressemitteilung der Imker. Es gebe nicht mehr grün blühende Wiesen, Ackerflächen mit Wildblumen umrankt, Kornblumen, Kleearten und Wildkräuter, Wald und Moore. Alles sei hauptsächlich in Agrarlandschaft umgewandelt. Viele nützliche Insekten ernähren sich nach Angaben der Imker heute von ganz anderen Pflanzen als noch vor 50 Jahren. Denn die Blüten, die sie eigentlich bevorzugen, gebe es heute gar nicht mehr. Der Einsatz von Insektiziden im deutschen Rapsanbau hat sich den Lingenern zufolge vervierfacht. Dennoch hätten es die Imker erreicht, das die Bienen auch weiter in unserer Landschaft bestäubend tätig sind. Dieses Wissen müsse an die jungen Imker weiter gereicht werden, hieß es.

DW looks at why people are taking to the streets in Germany to demand an "Agrarwende" - or agricultural transformation. Issues include health concerns, protection of animals, and pollution impacts on water and climate. Under the motto "we're sick of it!", people in Berlin will hit the streets by the thousands on Saturday (01.16.2016) to protest for a transformation in agricultural systems. A broad coalition of more than 50 environmental, consumer, animal and farming groups have called for the demonstration, which coincides with the opening of Green Week in Berlin - the largest agricultural trade fair in the world.

"Unsere Beobachtungen sind hochgradig beängstigend", sagt Josef Tumbrinck vom Naturschutzbund Deutschland (Nabu). Er warnt vor einem neuartigen Insektensterben mit unbekannten Folgen für Deutschland. Nach einer aktuellen Untersuchung ging im Bundesland Nordrhein-Westfalen in den vergangenen 15 Jahren die Masse an Insekten um 80 Prozent zurück. Eine ähnliche Entwicklung wird auch in anderen Regionen befürchtet. "Wenn uns die Fluginsekten fehlen, gerät die gesamte Nahrungskette in Gefahr: Blumen und Bäume werden nicht mehr bestäubt, und den Vögeln fehlt die Nahrungsgrundlage", sagt Tumbrinck, Vorsitzender vom Nabu in NRW. Der Umweltverband hatte zusammen mit Insektenkundlern zwischen 1989 und 2014 an 88 Standorten Insekten gesammelt, ihre Arten bestimmt und sie gewogen. "Während wir 1995 noch 1,6 Kilogramm aus den Untersuchungsfallen sammelten, sind wir heute froh, wenn es 300 Gramm sind", sagt Tumbrinck. Der Rückgang von bis zu 80 Prozent betreffe unter anderem Schmetterlinge, Bienen und Schwebfliegen. Besonders Neonicotinoide stehen im Verdacht, für das massenhafte Sterben von Insekten verantwortlich zu sein. Die hochwirksamen Insekten-Nervengifte werden seit Mitte der 1990er Jahre in der Landwirtschaft eingesetzt.

Kurzfassung aus dem Abstrakt: „Wir quantifizierten die Konzentrationen von Neonikotinoid-Insektiziden und Fungiziden im Pollen von Raps und im Pollen von Wildblumen, die in der Nähe von Ackerland wuchsen. …Pollen gesammelt von Bienen und Hummeln enthielt eine breite Palette an Pestiziden, einschließlich Carbendazim, Boscalid, Flusilazole, Metconazole, Tebuconazole and Trifloxystrobin und die Neonikotinoide Thiamethoxam, Thiacloprid und Imidacloprid. Bei Hummeln fanden sich die Fungizide Carbendazim, Boscalid, Tebuconazole, Flusilazole und Metconazole mit Konzentrationen bis zu 73 Nanogramm/Gramm (ng/g). Es ist bemerkenswert, dass Pollen, der von Bienen in ländlichen Gebieten gesammelt wurde, höhere Werte an den Neonikotinoiden Thiamethoxam (Mittel 18 ng/g) and Thiacloprid (Mittel 2.9 ng/g) aufweist, zusammen mit einer Reihe von Fungiziden, bei denen von einigen bekannt ist, dass sie synergistisch mit Neonikotinoiden wirken….. „ Kurz: Bienen, Wildbienen und Hummeln in Ackerbaugebieten sind sowohl von Seiten der Ackerkulturen – als auch von Seiten der wildblühenden Ackerbegleitflora mit einem vielfältigen Cocktail aus Pestiziden (Neonikotinoiden und Fungiziden) belastet. (Pyrethroide wurden dabei noch gar nicht untersucht). Es mag zwar mittlerweile durch die Einschränkung der drei Neonikotinoide Imidacloprid, Clothianidin und Thiamethoxam ein leichter Rückgang bei dieser bienengefährlichen Insektizidgruppe bei gleichzeitiger Verschiebungen zu Thiacloprid stattgefunden haben – dies ändert aber nichts an der Gesamtproblematik.