Beleid en debat

Wir verwenden ein spezielles Radargerät, um den Flug von einzelnen Bienen über Kilometer zu verfolgen. Das Design der Versuche zum Studium ihrer Navigationsleistungen besteht darin, Bienen nach einer Dressur auf einer Futterstelle oder nach dem Verfolgen einer Tänzerin am Stockausgang mit einem Transponder auszustatten und an einer anderen Stelle innerhalb ihres explorierten Areals freizulassen. Sie führen dann zuerst einen Vektorflug durch, der sie entweder zum Stock zurück gebracht hätte (wären sie nicht versetzt worden) oder zu der im Tanz angegebenen Futterstelle. Danach führen sie einen Suchflug durch, von dem sie auf direktem Flug zum Stock zurückkehren. Die Experimente sind so angelegt, dass die Bienen sich dabei nicht nach einem Horizontprofil oder einer Landmarke in der Nähe des Stockes, sondern ausschließlich nach der Bodenstruktur orientieren können. Wir weisen nach, dass das Navigationsgedächtnis der Bienen am besten als eine kognitive Karte beschrieben werden kann. Subletale Dosen von Neonicotinoiden stören selektiv die Heimflugphase, die auf der Verwendung dieses kartenartigen Gedächtnisses beruht, sodass die Tiere dann nicht mehr sicher zum Stock zurückfinden. Eine chronische Aufnahme von Thiacloprid reduziert die Sammelaktivität und die Tanzkommunikation.

In recent years, populations of honey bees and other pollinators have been reported to be in decline worldwide. A number of stressors have been identified as potential contributing factors, including the extensive prophylactic use of neonicotinoid insecticides, which are highly toxic to bees, in agriculture. While multiple routes of exposure to these systemic insecticides have been documented for honey bees, contamination from puddle water has not been investigated. In this study, we used a multi-residue method based on LC-MS/MS to analyze samples of puddle water taken in the field during the planting of treated corn and one month later. If honey bees were to collect and drink water from these puddles, our results showed that they would be exposed to various agricultural pesticides. All water samples collected from corn fields were contaminated with at least one neonicotinoid compound, although most contained more than one systemic insecticide. Concentrations of neonicotinoids were higher in early spring, indicating that emission and drifting of contaminated dust during sowing raises contamination levels of puddles. Although the overall average acute risk of drinking water from puddles was relatively low, concentrations of neonicotinoids ranged from 0.01 to 63 µg/L and were sufficient to potentially elicit a wide array of sublethal effects in individuals and colony alike. Our results also suggest that risk assessment of honey bee water resources underestimates the foragers' exposure and consequently miscalculates the risk. In fact, our data shows that honey bees and native pollinators are facing unprecedented cumulative exposure to these insecticides from combined residues in pollen, nectar and water. These findings not only document the impact of this route of exposure for honey bees, they also have implications for the cultivation of a wide variety of crops for which the extensive use of neonicotinoids is currently promoted.

This report provides an overview of the U.S. Geological Survey National Water-Quality Assessment program and National Stream Quality Accounting Network findings for pesticide occurrence in U.S. streams and rivers during 2002–11 and compares them to findings for the previous decade (1992–2001). In addition, pesticide stream concentrations were compared to Human Health Benchmarks (HHBs) and chronic Aquatic Life Benchmarks (ALBs). The comparisons between the decades were intended to be simple and descriptive. Trends over time are being evaluated separately in a series of studies involving rigorous trend analysis. During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time. In contrast, alachlor, chlorpyrifos, cyanazine, diazinon, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams during the second decade than during the first decade.

The populations of most types of Finnish water fowl have been declining steadily and aggressively for many years, a new study shows. The results of the study, conducted by the Finnish Game and Fisheries Research Institute (RKTL) and the Finnish Museum of Natural History, were published in the European Journal of Wildlife Research. Species of water bird whose numbers are swiftly dwindling include the widgeon (Anas penelope), the northern pintail (Anas acuta), the garganey (Anas querquedula), the tufted duck (Aythya fuligula), the pochard (Aythya ferina) and the coot (Fulica atra). Researchers say the drops are due to changes in the birds’ habitat; feeding becomes difficult for water fowl in hypertrophic or polluted waters. The research centre calls the population depletion a ”mystery,” since extra nutrients in the waters should make it easier for birds to feed. Shifts in the food chain may also affect the nutritional intake of young fowls, and small mammalian predators or other birds can eat the young of other species or destroy their nests.

A mixture of insecticides used in corn production was monitored over a three-year period in a field study to determine how long each persists in the environment, where each insecticide travels within the corn field, and the efficacy of using soil-applied insecticides with genetically modified corn. The genetically modified corn contained the insecticidal Cry1Ab and Cry3Bb1 proteins (Bt corn) and the Cry1Ab protein was found to persist only during the corn growing season in soil, runoffwater, and runoff sediment with highest concentrations measured during pollination. Very low concentrations of Cry1Ab proteins were measured in soil collected in the non-Bt corn field, and no Cry1Ab proteins were detected in shallow groundwater or soil pore water. Clothianidin, a neonicotinoid insecticide used as a seed coating, was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin, a pyrethroid insecticide applied at planting to control corn rootworm larvae (Diabrotica spp., Coleoptera: Chrysomelidae) populations, was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not detected in groundwater or soil pore water. Tefluthrin did not have an effect on root damage from corn rootworm larvae feeding to Bt corn, but did prevent damage to non-Bt corn. A slight reduction in grain yield was observed in the non-Bt, no tefluthrin treatment when compared to all other treatments, but no significant difference in grain yield was observed among Bt corn treatments regardless of soil insecticide application. In the current study, the use of tefluthrin on Bt corn did not significantly affect crop damage or yield, and tefluthrin may travel off-site in runoff water and sediment.