Overige insecten

Honey bees are exposed to a wealth of synergistically interacting stress factors, which may induce colony losses often associated with high infection levels of pathogens. Neonicotinoid insecticides have been reported to enhance the impact of pathogens, but the underlying immune alteration is still obscure. In this study we describe the molecular mechanism through which clothianidin adversely affects the insect immune response and promotes replication of a viral pathogen in honey bees bearing covert infections. Our results shed light on a further level of regulation of the immune response in insects and have implications for bee conservation.

A study published in the journal Science, reveals that the number of slugs, spiders, worms and other invertebrates has fallen by 45 per cent over the past 35 years. Experts fear this will harm the planet as creepy crawlies play an important role in pollinating crops, pest control, decomposition and ensuring soil remains packed with nutrients, as well as water filtration. In the UK the number of beetles, butterflies, bees and wasps has fallen by up to 60 per cent. Experts warn that fewer insects would have a huge effect on crop production as up to 75 percent are pollinated by insects, amounting to around 10 per cent of the world's food supply. Scientists fear a drop in the insect population could also spark a decline in birds, which prey on pests that damage crops, and amphibians, which help keep water supplies free from algae.

The European Food Safety Authority (EFSA) was asked by the European Commission to perform an evaluation of imidacloprid as regards the risk to aquatic organisms. In this context the conclusions of EFSA concerning the risk assessment for aquatic organisms for the active substance imidacloprid are reported. The context of the evaluation was that required by the European Commission in accordance with Article 21 of Regulation (EC) No 1107/2009 to review the approval of active substances in light of new scientific and technical knowledge and monitoring data. The conclusions were reached on the basis of the evaluation of the representative uses of imidacloprid authorised at the time of approval of the substance. The proposed endpoints concluded as being most appropriate for use in regulatory risk assessment, derived from the submitted studies and literature data, are presented. Missing information identified as being required to allow for a complete risk assessment is listed.

Herbicides are widely used pesticides that affect plants by changing their chemistry. In doing so, herbicides might also influence the quality of plants as food for herbivores. To study the effects of herbicides on host plant quality, 3 plant species (Plantago lanceolata L., P. major L., and Ranunculus acris L.) were treated with sublethal rates of either a sulfonylurea (Atlantis WG, Bayer CropScience) or a glyphosate (Roundup LB Plus, Monsanto) herbicide, and the development of caterpillars of the cabbage moth Mamestra brassicae L. that fed on these plants was observed.
Of the 6 tested plant–herbicide combinations, 1 combination (R. acris + sulfonylurea herbicide) resulted in significantly lower caterpillar weight, increased time to pupation, and increased overall development time compared with larvae that were fed unsprayed plants. These results might be caused by a lower nutritional value of these host plants or increased concentrations of secondary metabolites that are involved in plant defense. The results of the present and other studies suggest potential risks to herbivores that feed on host plants treated with sublethal rates of herbicides. However, as the effects of herbicides on host plant quality appear to be species-specific and as there are numerous plant–herbicide–herbivore relationships in agricultural landscapes, a general reduction in herbicide contamination of nontarget habitats (e.g., field margins) might mitigate the negative effects of herbicides on host plant quality.

Pour François Ramade, professeur émérite d'écologie à l'université de Paris-Sud, les insecticides modernes, notamment les néonicotinoïdes, sont responsables d'une véritable "catastrophe écologique". Et, selon lui, "la réponse des pouvoirs publics des pays développés et des institutions multilatérales est absente ou dérisoire". Les personnes de plus de 40 ans se souviennent des pare-brise, phares et calandres de voiture constellés de cadavres d'insectes. La propreté des voitures actuelles est le signe d'une disparition massive d'insectes qui doit nous alarmer. L'agriculture moderne a permis, par l'usage massif d'« intrants », une augmentation considérable de la productivité des cultures. Elle atteint depuis quelques décennies des limites dues à l'impact environnemental de ses pratiques. En effet, l'accroissement de productivité qu'elle a permis n'est pas dû à une révolution biologique dans le contrôle de la photosynthèse, mais à un recours sans cesse accru aux engrais chimiques et aux pesticides, dont les conséquences écologiques néfastes sont connues.

Neonicotinoid insecticides exhibit very high toxicity to a wide range of invertebrates, particularly insects, and field-realistic exposure is likely to result in both lethal and a broad range of important sublethal impacts. The compounds are highly persistent in soils, tend to accumulate in soils and sediments, have a high runoff and leaching potential to surface and groundwater and have been detected frequently in the global environment. For imidacloprid, including its neurotoxic metabolites, lethal toxicity can increase up to 100,000 times compared to acute toxicity when the exposure is extended in time (Suchail et al. 2001). Recent studies have shown that chronic toxicity of neonicotinoids can more adequately be expressed by time to 50 % mortality instead of by the 10 day LD50 (Sánchez-Bayo 2009; Maus and Nauen 2010; Tennekes 2010; Tennekes 2011; Tennekes and Sánchez-Bayo 2012; Mason et al. 2013; Rondeau et al. 2014). There is a linear relation between the logarithm of the daily dose and the logarithm of the time to 50 % mortality (Tennekes 2010, 2011; Tennekes and Sánchez-Bayo 2012; Tennekes and Sánchez-Bayo 2013; Rondeau et al. 2014).