Overige insecten

Recent research in Europe and North American has shown that very low concentrations of neonicotinoid insecticides, in some cases even less than 50 parts per billion, can affect the foraging behavior of bees and the health of colonies. Neonicotinoids are a group of insecticides with a chemical structure similar to nicotine. The active ingredients of neonicotinoid products used in greenhouses include imidacloprid, acetamiprid, dinotefuran and thiamethoxam. One reason that neonicotinoid products have been favored is because they are absorbed by plant roots and circulate in the plant.

For at least one member of a controversial class of insecticides, low doses may cause as much harm to nontarget insects as high doses do, according to a new study. The number of offspring that fruit flies produce drops significantly when the insects are chronically exposed to nanomolar concentrations of imidacloprid, a member of the neonicotinoid insecticide group (Environ. Sci. Technol. 2014, DOI: 10.1021/es405331c). In Europe, policymakers have moved to temporarily ban some of the neonicotinoids based in part on previous studies that showed that honeybees exposed to low doses of the compounds developed significant behavioral changes. The new study builds on these low-dose findings and suggests regulators need to rethink how they assess the safety of chemicals applied in the environment, says Dennis vanEngelsdorp, an entomologist at the University of Maryland, College Park, who wasn’t involved in the work.

Wenn es im Herbst ab und an in der Hecke raschelt, dann sucht wahrscheinlich ein kleiner Igel Deckung und wühlt sich unter die Blätterhaufen. Vielleicht sucht er hier auch nach einer Schnecke, um seinen Hunger zu vertreiben. Roland Seime ist der Mann, der sich im Saale-Holzland-Kreis und Jena um Igeljunge kümmert, die den Herbst alleine nicht überleben würden. Er nimmt sie bei sich auf und pflegt sie in seiner Igelstation in Jena-Winzerla. Zur Zeit wachen seine kleinsten Igeljungen aus dem Winterschlaf auf. "Sie haben Hunger und müssen fressen", sagt er. Die kleinen Tiere sind auf Futtersuche, weshalb es sein kann, dass man sie am Tag auch in der freien Wildbahn sieht. Denn eigentlich sind Igel nachtaktiv und wollen sich tagsüber verstecken und schlafen. Roland Seime hält zwei Jungtiere in seinen Händen, die es jeweils gerade einmal auf 400 Gramm bringen. "Sie sind schon wach, um nach Nahrung zu suchen", sagt er. "Sonst würden sie nicht überleben."

Neonicotinoids are subjected to vigilance because of environmental contaminations and deleterious effects on bees. Imidacloprid (IMI) is one of the most representative insecticides of this family. At chronic exposure, concentration-effect relationships are non linear. An insect model should allow a better description of this toxicity. We compared the lethal concentration 50% (LC50) of IMI for a Drosophila-field strain, after acute and chronic exposure. Relative to the acute LC50, the chronic LC50 was lowered by a factor of 29 for males (1.3 mM/45 µM), 52 for larvae (157 µM/3µM) and more than 172 for females (>3.1mM/18µM). Chronic exposure also revealed significant lethal and sublethal effects, at concentrations 3-5 orders of magnitude lower than the chronic LC50. Mean mortalities reached 28% (at 3.91 nM) and 27% (at 39.1 nM) for females and males, respectively. Fecundity decreased of 16% at 1.96 nM. Mating increased of 30% at 0.391 nM. The LOEC (Lowest Observed Effect Concentration: 0.391 nM) was 46000 times lower than the chronic LC50 for males; it was 115000 times lower than the chronic LC50 for females. This study illuminates effects that neonicotinoids can induce at very low concentrations. This is of particular interest for non-target insects and for insect dependent species.

Anfang April (2014) fand die erste Bienenschutzkonferenz in den Tagungsräumen des Schlosses Schönbrunn in Wien statt. Ausrichterin der zweitägigen Veranstaltung war Global 2000, Österreichs führende, unabhängige Umweltschutzorganisation. Die Veranstaltung war mit internationalen Referenten hochkarätig besetzt. Die Themenvielfalt bot Einblicke, die alle Imker angehen. Gegliedert war die Konferenz in vier Themenblöcke, die sich unterschiedlichen Schwerpunkten widmeten: Teil-Verbot von Neonicotinoiden in der EU-Landwirtschaft: ausreichend zum Schutz der Bienen? Multifaktorelle Belastungen für (Wild-)Bienenpopulationen und deren Folgen. Konzepte für den Bienenschutz. Bienenfreundliche Lebensräume schaffen, erhalten und fördern.

The effect of the insecticide Tanrec® at concentrations of 3.0 × 10–7, 3.0 ×10–2, and 3.0 × 10–1 mg/L (as of imidacloprid) on Daphnia magna Straus has been studied. An acute toxic effect of this insecticide at a concentration of 3.0 × 10–1 mg/L and a depressive effect at concentrations of 3.0 × 10–2 mg/L and 3.0 × 10–7 have been revealed. A damaging effect of Tanrec was revealed during the stage of early development of studied crustaceans. This effect was manifested in the inhibition of the growth of oocytes, abnormal functioning of the intestine, retardation of body growth, and pathological changes in tissues.