Overige insecten

Und wenn es plötzlich keine Insekten mehr gäbe? Die Entomologen stellen sich die Frage immer wieder, und wenn auch die Prognosen variieren, so herrscht in einem Punkt Einigkeit: Das menschliche Leben, wie wir es kennen, würde wahrscheinlich enden. Der namhafte Entomologe Edward O. Wilson, ausgezeichnet mit zwei Pulitzerpreisen und der National Medal of Science, gibt den Menschen nach dem hypothetischen Aussterben aller Wirbellosen (von denen Insekten die Mehrzahl stellen) noch zehn Jahre. Der Science-fiction-Autor Charles Pellegrino dagegen, der in seinem Roman «Dust» die katastrophalen Folgen eines globalen, programmierten Aussterbens aller Insekten beschreibt, lässt es weniger als sechs Monate dauern, bis die Menschheit auf eine Hand voll bedauernswerte, in alle Welt zerstreute Überlebende geschrumpft ist.

Imidacloprid is a systemic insecticide effective in controlling the exotic pest Adelges tsugae (hemlock woolly adelgid) in eastern hemlock (Tsuga canadensis) trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil injection in two sites at Coweeta Hydrologic Laboratory in western North Carolina. Soils differed in profile depth, total carbon and nitrogen content, and effective cation exchange capacity. We injected imidacloprid 5 cm into mineral soil, 1.5 m from infested trees, using a Kioritz soil injector. We tracked the horizontal and vertical movement of imidacloprid by collecting soil solution and soil samples at 1 m, 2 m, and at the drip line from each tree periodically for 1 yr. Soil solution was collected 20 cm below the surface and just above the saprolite, and acetonitrile-extractable imidacloprid was determined through the profile. Soil solution and extractable imidacloprid concentrations were determined by high-performance liquid chromatography. Soil solution and extractable imidacloprid concentrations were greater in the site with greater soil organic matter. Imidacloprid moved vertically and horizontally in both sites; concentrations generally declined downward in the soil profile, but preferential flow paths allowed rapid vertical movement. Horizontal movement was limited, and imidacloprid did not move to the tree drip line. We found a negative relationship between adsorbed imidacloprid concentrations and soil microarthropod populations largely in the low-organic-matter site; however, population counts were similar to other studies at Coweeta.

The coming together of a major problem and a leading problem-solver can be a significant moment, and we witnessed one such last week with the news that Professor Bob Watson is going to have a close personal look at the issue of neonicotinoids, the new nerve-agent pesticides, and their effect on bees and other pollinating insects. For Bob Watson is a towering figure, and that is the bigger significance: he is the world's leading expert on policy responses to global change, on what we should do about climate change, the loss of wildlife, the destruction of ecosystems and the need to feed a world of nine billion people – and in particular, on how we should respond as a society when all these difficulties come together, as they are now. On Monday, the Defra website carried its own story headlined: "Myth Busters", saying the Independent story was not true. It said: "The truth: Bob Watson did not order a review of the evidence......he asked to receive regular updates on new research into the possible effects on insects which are not the target species of pesticides." This is what Bob Watson told me on Friday: "The real Defra position is the following. We will absolutely look at the University of Stirling work, the French work, and the American work that came out a couple of months ago. We must look at this in real detail to see whether or not the current British position is correct or is incorrect." If that's not a review of the evidence, what is? The Xerces Society for Invertebrate Conservation recently published a review of research into the effects of neonicotinoid insecticides on bees, with recommendations for action (attached).

Dear Editor,
Sir Robert Watson, chief scientist at the Department of the Environment (Defra), has acted bravely in ordering a reassessment of the licensing of neonicotinoid pesticides in the UK.
Watson faces an uphill struggle; Defra, its Food and Environment Research Agency and the Advisory Committee on Pesticides have all resolutely ignored the many peer-reviewed studies from Europe, from as long ago as 1999, which proved the extreme toxicity of neoniocotinoids for honeybees, bumblebees and butterflies.
The wildlife NGOs are similarly in denial. With the honourable exception of Buglife, all have stood by silently as bees, pollinating insects, soil-invertebrates and farmland birds are wiped from the face of Britain's countryside.
Painful as it may be for Defra, the ACP and the leading wildlife bodies to admit that they got this wrong, they must call for a complete ban on these poisons now, or we will suffer complete ecological disaster in this country.