Beleid en debat

Daran, dass unsere Insekten und damit auch unsere Vögel weniger werden, sollen hauptsächlich Pflanzenschutzmittel schuld sein. Jetzt haben Forscher aus Tokio bestätigt, dass sich Neonicotinoide auch im Wasser und damit auf Fische auswirken. Ein Team um Masumi Yamamuro von der Universität Tokio hat den japanischen Shinji-See über Jahrzehnte beobachtet. Der siebtgrößte See Japans liegt in der Präfektur Shimane, an seinen Ufern befinden sich Reisfelder.

Leonard et al. (1) presented an interesting approach to limit the impact of pathogens on honeybees by stimulating immunity via engineered symbionts. The urgency to safeguard pollinator services is undoubted. Massive declines in bees, insects in general, pose major concerns for ecosystem stability and food production. However, we see potential pitfalls in such technology driven approaches. Leonard et al. attribute high honeybee colony mortality to the parasitic mite Varroa destructor via synergistic interactions with RNA viruses. However, Varroa is only a significant concern for honeybees.

Our mechanistic understanding of the toxicity of chemicals that target biochemical and/or physiological pathways, such as pesticides and medical drugs is that they do so by binding to specific molecules. The nature of the latter molecules (e.g., enzymes, receptors, DNA, proteins, etc.) and the strength of the binding to such chemicals elicit a toxic effect in organisms, which magnitude depends on the doses exposed in a given timeframe.

Based on the science available to date, there is evidence to support the claim that bats are being negatively affected by neonicotinoid insecticides in several different ways, indirectly through reduction in insect abundance and directly through impairment.

The “fates of humans and insects are intertwined”, scientists have said, with the huge declines reported in some places only the “tip of the iceberg”. The warning has been issued by 25 experts from around the world, who acknowledge that little is known about most of the estimated 5.5 million insect species. However, enough was understood to warrant immediate action, they said, because waiting for better data would risk irreversible damage.

Short-term peaks of contaminant concentrations and flows go undetected at many minesites. Recent biological studies have shown that short peaks can contribute significantly to toxicity due to aspects like damage per unit of time, accumulating damage through time, damage at any concentration, temporally aligned or offset synergistic and antagonistic interactions, and slowly reversible or non-reversible uptake and binding of some metals and other elements.

Neonicotinoid insecticides, also known as neonics, are doing more than killing bees and other insects in record numbers, according to a report issued last month by the Natural Resources Defense Council, an international environmental advocacy group. Neonics, the council says, are contaminating New York State’s soil and water and “hollowing out ecosystems from the bottom up.”

Bumblebee populations in North America and Europe have plummeted, according to a study published Thursday in the journal Science. The number of areas populated by bumblebees has fallen 46 percent in North America and 17 percent in Europe. The loss of bumblebee populations is alarming because they play a central role in pollinating many plants, including key crops such as tomatoes and cranberries.