Honeybees

The dramatic loss of honey bees is a major concern worldwide. Previous studies have indicated that neonicotinoid insecticides cause behavioural abnormalities and have proven that exposure to sublethal doses of imidacloprid during the larval stage decreases the olfactory learning ability of adults. The present study shows the effect of sublethal doses of imidacloprid on the neural development of the honey bee brain by immunolabelling synaptic units in the calyces of mushroom bodies. We found that the density of the synaptic units in the region of the calyces, which are responsible for olfactory and visual functions, decreased after being exposed to a sublethal dose of imidacloprid. This not only links a decrease in olfactory learning ability to abnormal neural connectivity but also provides evidence that imidacloprid damages the development of the nervous system in regions responsible for both olfaction and vision during the larval stage of the honey bee.

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.

In its first scientific risk assessment of the much-debated class of pesticides called neonicotinoids and how they affect bees on a chronic long-term basis, the EPA found in some cases the chemical didn't harm bees or their hives but in other cases it posed a significant risk. It mostly depended on the crop, a nuanced answer that neither clears the way for an outright ban nor is a blanket go-ahead for continued use. Before acting, EPA said it needed more specific and targeted research and this is the first of four planned assessments of risk of specific neonicotinoids. It will be announced Wednesday, but The Associated Press obtained the summary earlier and the chief pesticide official explained the results in an interview. The study was done by the EPA and California's environmental agency, with a similar one done by Canada being released Wednesday at the same time. EPA analysis of detailed tests found a clear level of concentration of the pesticide imidacloprid, the most common neonicotinoid, in which things start to go awry. If nectar brought back to the hive from worker bees had more than 25 parts per billion of the chemical, "there's a significant effect," namely fewer bees, less honey and "a less robust hive," said Jim Jones, EPA's assistant administrator for chemical safety and pollution prevention. But if the nectar chemical level was below 25 parts per billion, it was as if there were no imidacloprid at all, with no ill effects, Jones said.

Scientists at Sussex University claim new research shows the impact on bees of neonicotinoid pesticides is even greater than originally feared. The researchers, at Sussex University, say they have discovered that bees are exposed to a chemical cocktail when feeding from wildflowers growing next to neonicotinoid treated crops in UK farmland. The scientists claim these chemical cocktails could make the impact of neonicotinoids up to 1,000 times more potent than previously thought. The Sussex University research, supported by the Soil Association – the organic food and farming organisation – says that pollinators consuming pollen from these crops or from nearby wildflowers will ingest a cocktail of fungicides and insecticides. It goes on: “A prior study suggests these fungicides could act synergistically, making the insecticides up to 1,000 times more deadly than they are on their own.”

Wild bees, crucial pollinators for many crops, are on the decline in some of the main agricultural regions of the United States, according to scientists who produced the first national map of bee populations and identified numerous trouble spots. The researchers on Monday cited 139 counties as especially worrisome, with wild bee numbers decreasing while farmland for crops dependent on such pollinators is increasing. The counties included agricultural regions of California such as the Central Valley, as well as the Pacific northwest, the upper midwest and Great Plains, west Texas and the southern Mississippi river valley. The counties grew crops such as almonds, pumpkins, squashes, blueberries, watermelons, peaches and apples that are highly dependent on pollinators, or had large amounts of less-pollinator-dependent crops including soybeans, canola and cotton. Taylor Ricketts, director of the University of Vermont’s Gund Institute for Ecological Economics, said the 139 counties represent 39% of the pollinator-dependent crop area of the United States and most likely will face inadequate pollination in the future. “Wild bee declines may increase costs for farmers and, over time, could even destabilize crop production,” Ricketts said.

Wissenschaftler sprechen inzwischen bereits von einem zweiten „Stummen Frühling“, wie er zuletzt in den 1950er und 1960er Jahren durch das Insektengift DDT ausgelöst wurde: Über die Nahrungskette gelangen giftige Pflanzenschutzmittel beständig auch in Lebewesen, die am Ende der Nahrungskette stehen, und gefährden diese immens. Die Kritik der Wissenschaftler ist dabei zwar erstklassig belegt – sie wird von der Industrie jedoch nicht etwa aufgegriffen, sondern massiv bekämpft. Über die Macht der Agrochemie-Riesen in der Forschung und über die Folgen unserer aktuellen Art, Landwirtschaft zu betreiben, sprach Jens Wernicke mit Angelika Hilbeck, Dozentin am Departement Umweltsystemwissenschaften der Eidgenössisch Technischen Hochschule Zürich.

To determine the exposure of native bees to pesticides, bees were collected from an existing research area in northeastern Colorado in both grasslands (2013–2014) and wheat fields (2014). Traps were deployed bi-monthly during the summer at each land cover type and all bees, regardless of species, were composited as whole samples and analyzed for 136 current-use pesticides and degradates. This reconnaissance approach provides a sampling of all species and represents overall pesticide exposure (internal and external). Nineteen pesticides and degradates were detected in 54 composite samples collected. Compounds detected in > 2% of the samples included: insecticides thiamethoxam (46%), bifenthrin (28%), clothianidin (24%), chlorpyrifos (17%), imidacloprid (13%), fipronil desulfinyl (7%; degradate); fungicides azoxystrobin (17%), pyraclostrobin (11%), fluxapyroxad (9%), and propiconazole (9%); herbicides atrazine (19%) and metolachlor (9%). Concentrations ranged from 1 to 310 ng/g for individual pesticides. Pesticides were detected in samples collected from both grasslands and wheat fields.