Insecticiden

This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1) Varroa destructor mite infestation rate in October 2011, (2) presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen), (3) presence of Brassica napus (oilseed rape) or Sinapis arvensis (wild mustard) pollen in bee bread in early August 2011, and (4) a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid.

Pope Francis slams both GMOs and pesticides in a draft of his major environmental document that was leaked Monday. On pesticides Pope Francis states; “We get sick, for example, due to inhalation of large amounts of smoke produced by fuels used for cooking and heating. This is added to by….fertilizers, insecticides, fungicides, herbicides and toxic pesticides in general. Technology that is linked to finance, claims to be only solving problems…this solves a problem by creating others. “It creates a vicious circle in which the intervention of the human being to solve a problem often worsens the situation further. For example, many birds and insects die out as a result of toxic pesticides created by technology, they are useful to agriculture itself, and their disappearance will be compensated with another technological intervention that probably will bring new harmful effects… looking at the world we see that this level of human intervention, often in the service of finance and consumerism, actually causes the earth we live in to become less rich and beautiful, more and more limited and gray, while at the same time the development of technology and consumerism continues to advance without limits.”

Two species, the fathead minnow Pimephales promelas and the amphipod Hyalella azteca, were tested to examine acute toxicity to two insecticides, cyfluthrin and imidacloprid individually and as a mixture. Cyfluthrin was acutely toxic to P. promelas and H. azteca with EC50 values and 95 % confidence intervals of 0.31 µg L−1 (0.26–0.35 µg L−1) and 0.0015 µg L−1 (0.0011–0.0018 µg L−1), respectively. Imidacloprid was not acutely toxic to P. promelas at water concentrations ranging from 1 to 5000 µg L−1, whereas it was toxic to H. azteca with a EC50 value of 33.5 µg L−1 (23.3–47.4 µg L−1). For the P. promelas mixture test, imidacloprid was added at a single concentration to a geometric series of cyfluthrin concentrations bracketing the EC50 value. A synergistic ratio (SR) of 1.9 was found for P. promelas, which was calculated using the cyfluthrin-only exposure and mixture-exposure data. Because cyfluthrin and imidacloprid were toxic to H. azteca, the mixture test was designed based on an equipotent toxic unit method. Results from the mixture test indicated a model deviation ratio (MDR) of 1.7 or 2.7 depending on the model. Mixture test results from the simultaneous exposure to cyfluthrin and imidacloprid with both species indicated a greater than expected toxic response because the SR or MDR values were >1. Because these two insecticides are commonly used together in the same product formulations, nontarget species could be more affected due to their greater-than-additive toxicity observed in the current study.

Two studies published in Nature last week have raised more concerns about whether neonicotinoid pesticides adversely affect bee health. One study shows that bees are drawn to neonicotinoids, possibly because the insects catch a “buzz” from the pesticides similar to the one humans get from nicotine (2015, DOI: 10.1038/nature14414). The other study suggests that neonicotinoids affect bee behavior and growth under realistic conditions in a crop field (2015, DOI: 10.1038/nature14420).

Two new reports on Europe’s endangered fish and bird species were released this week by the International Union for Conservation of Nature (IUCN). The first report is itself a milestone: the first full assessment of all of Europe’s 1,220 marine fish species. The study found that 7.5 percent of those species were threatened with extinction. Worst hit, as we’ve seen before, were sharks, rays and chimaeras. A full 40.4 percent of those European species (known collectively as chondrichthians) face the threat of extinction and nearly that many have declining populations. The second report looked at all 533 bird species that spend at least part of their time in Europe and found that 13 percent are threatened. Four species have been declared regionally extinct in Europe. Others, such as the sociable lapwing (Vanellus gregarius), aren’t far behind. Another 28 species have been assessed as endangered or critically endangered on the continent. Most of these are also at risk through the remainder of their ranges.

We studied the effects of sublethal doses of imidacloprid on olfactory learning in the native honey bee species, Apis cerana, an important pollinator of agricultural and native plants throughout Asia. We provide the first evidence that imidacloprid can impair learning in A. cerana workers exposed as adults or as larvae. Adults that ingested a single imidacloprid dose as low as 0.1 ng/bee had significantly reduced olfactory learning acquisition, which was 1.6-fold higher in control bees. Longer-term learning (1-17 h after the last learning trial) was also impaired. Bees exposed as larvae to a total dose of 0.24 ng/bee did not have reduced survival to adulthood. However, these larval-treated bees had significantly impaired olfactory learning when tested as adults: control bees exhibited up to 4.8-fold better short-term learning acquisition, though longer-term learning was not affected.

On May 29th, the Day of the Honey Bee in Quebec, Équiterre, in collaboration with the David Suzuki Foundation, hosted a public talk presenting the results of the most important literature review on the impacts of neonicotinoïd pesticides, that kill pollinators. The comprehensive assessment of more than 1,000 peer-reviewed reports was conducted by the international Task Force on Systemic Pesticides, an international group of 50 independent scientists. The talk was given by Jean-Marc Bonmatin, researcher at the French National Centre for Scientific Research (CNRS) and Task Force vice-chair, and Madeleine Chagnon, PhD, associate professor at the Department of Biological Sciences at the Université du Québec à Montréal, who also participated to the Task Force. "As a scientist, I can now say conclusively that the evidence of harm is clear and points to the urgent need for action to reduce the quantities of these pesticides entering the environment," said Bonmatin.