English

The aim of this study was to investigate whether Roundup® (a glyphosate-based herbicide) leads to neurotoxicity in hippocampus of immature rats following acute (30min) and chronic (pregnancy and lactation) pesticide exposure. Maternal exposure to pesticide was undertaken by treating dams orally with 1% Roundup® (0.38% glyphosate) during pregnancy and lactation (till 15-day-old). Hippocampal slices from 15 day old rats were acutely exposed to Roundup® (0.00005-0.1%) during 30min and experiments were carried out to determine whether glyphosate affects 45Ca2+ influx and cell viability. Moreover, we investigated the pesticide effects on oxidative stress parameters, 14C-α-methyl-amino-isobutyric acid (14C-MeAIB) accumulation, as well as glutamate uptake, release and metabolism. Results showed that acute exposure to Roundup® (30min) increases 45Ca2+ influx by activating NMDA receptors and voltage-dependent Ca2+ channels, leading to oxidative stress and neural cell death.

Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ~11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples.

On March 18, a majority of Dutch parliament rallied behind a motion of the Animal Welfare Party for a national ban on the use of all neonicotinoid insecticides in agriculture and retail sales. The Party for Animal Welfare has been campaigning for many years against the neonicotinoids. In early 2013 a parliamentary majority endorsed a motion of Esther Ouwehand for a European ban on the pesticides. Due to this motion the use of three types of neonicotinoids: imidacloprid, clothianidin and thiamethoxam is now restricted in all 27 countries of the EU. However, the European ban on neonicotinoids only applies to selected crops which are attractive to bees like sunflowers, canola and maize; this means that as much as 80 % of crops which are treated with neonicotinoids in the Netherlands remain unaffected by the EU ban. Dutch Parliament now forced Secretary of State Dijksma to take further action. A majority of political parties: PvdA , SP, GL , D66 , 50 + and Freedom Party, endorsed a ban on ALL neonicotinoids in the Netherlands for all uses in agriculture, domestic gardens and landscape uses. The motion which was passed also demanded a complete ban on a related systemic pesticide, fipronil.

Pesticides have a direct impact on the physiology and behaviour of earthworms, a Danish/French research team reports after having studied earthworms that were exposed to pesticides over generations. "We see that the worms have developed methods to detoxify themselves, so that they can live in soil sprayed with fungicide. They spend a lot of energy on detoxifying, and that comes with a cost: The worms do not reach the same size as other worms, and we see that there are fewer of them in sprayed soil. An explanation could be that they are less successful at reproducing, because they spend their energy on ridding themselves of the pesticide", the researchers, Ph. D. student Nicolas Givaudan and associate professor, Claudia Wiegand, say.

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.

House sparrows, once a prominent presence in many villages and towns in southern state of Kerala, are fast disappearing from capital Thiruvananthapuram. A recent bird survey conducted ahead of the 'World Sparrow Day' which falls on Thursday could spot only about 127 sparrows in the city, Press Trust of India (PTI) reported. A group of amateur bird watchers with the support of World Widelife Fund-Kerala spent three days looking for sparrows in various locations in the city, where the birds could be seen in high numbers in the past.

Microbial pathogens are thought to have a profound impact on insect populations. Honey bees are suffering from elevated colony losses in the northern hemisphere possibly because of a variety of emergent microbial pathogens, with which pesticides may interact to exacerbate their impacts. To reveal such potential interactions, we administered at sublethal and field realistic doses one neonicotinoid pesticide (thiacloprid) and two common microbial pathogens, the invasive microsporidian Nosema ceranae and black queen cell virus (BQCV), individually to larval and adult honey bees in the laboratory. Through fully crossed experiments in which treatments were administered singly or in combination, we found an additive interaction between BQCV and thiacloprid on host larval survival likely because the pesticide significantly elevated viral loads. In adult bees, two synergistic interactions increased individual mortality: between N. ceranae and BQCV, and between N. ceranae and thiacloprid. The combination of two pathogens had a more profound effect on elevating adult mortality than N. ceranae plus thiacloprid. Common microbial pathogens appear to be major threats to honey bees, while sublethal doses of pesticide may enhance their deleterious effects on honey bee larvae and adults.

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.

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.