Insecticides

Honey bees provide key ecosystem services. To pollinate and to sustain the colony, workers must walk, climb, and use phototaxis as they move inside and outside the nest. Phototaxis, orientation to light, is linked to sucrose responsiveness and the transition of work from inside to outside the nest, and is also a key component of division of labour. However, the sublethal effects of pesticides on locomotion and movement to light are relatively poorly understood. Thiamethoxam (TMX) is a common neonicotinoid pesticide that bees can consume in nectar and pollen.

Birds that travel long distances between their wintering and breeding grounds may be particularly susceptible to neurotoxic insecticides, but the influence of insecticides on migration ability is poorly understood. Following acute exposure to two widely used agricultural insecticides, imidacloprid (neonicotinoid) and chlorpyrifos (organophosphate), we compared effects on body mass, migratory activity and orientation in a seed-eating bird, the white-crowned sparrow (Zonotrichia leucophrys).

Scientists and public health experts are alarmed by the phenomenon, which they suspect to be symptomatic of underlying toxicity in the environment and the food chain. “Missing eyes, deformed hind legs, missing limbs, extra limbs, partial limbs, limbs that are bent or bony, and abnormally thin or weak limbs are some of the reported frog abnormalities in the Western ghats,” said Dr. S. Muralidharan from the Division of Ecotoxicology at Salim Ali Centre for Ornithology & Natural History.

Der Entomologische Verein Krefeld, der seit 1905 Insekten erforscht, hat festgestellt, dass in den letzten 20 Jahren 80% unserer Fluginsekten verschwunden sind: http://80.153.81.79/~publ/mitt-evk-2013-1.pdf . Mit in 2 Malaise-Fallen gefangenen Insekten wurden dieser Verlust in einem Naturschutzgebiet ermittelt. Nicht nur eine industrialisierte Landwirtschaft und die damit verbundene Vernichtung der Lebensräume von Insekten sind dafür ursächlich.

The UK will back a total ban on insect-harming pesticides in fields across Europe, the environment secretary, Michael Gove, has revealed. The decision reverses the government’s previous position and is justified by recent new evidence showing neonicotinoids have contaminated the whole landscape and cause damage to colonies of bees. It also follows the revelation that 75% of all flying insects have disappeared in Germany and probably much further afield, a discovery Gove said had shocked him.

Neonicotinoids are widely used insecticides, but their use is subject of debate because of their detrimental effects on pollinators. Little is known about the effect of neonicotinoids on other beneficial insects such as parasitoid wasps, which serve as natural enemies and are crucial for ecosystem functioning. Here we show that sublethal doses of the neonicotinoid imidacloprid impair sexual communication and host finding in the parasitoid wasp Nasonia vitripennis. Depending on the dose, treated females were less responsive to the male sex pheromone or unable to use it as a cue at all.

In this study, effects of two neonicotinoid insecticides, imidacloprid and dinotefuran, on aquatic insect assemblages were evaluated in experimental rice mesocosms. During the 5-month period of the rice-growing season, residual concentrations of imidacloprid were 5–10 times higher than those of dinotefuran in both soil and water. Imidacloprid treatment (10 kg/ha) reduced significantly the populations of, Crocothemis servilia mariannae and Lyriothemis pachygastra nymphs, whereas those of Orthetrum albistylum speciosum increased slightly throughout the experimental period.

7 years ago I spoke out in favor of a ban on neonicotinoids. These are cumulative poisons without thresholds that contaminate entire areas of the country and, moreover, are only slowly degraded. It's a nearly perfect script for insect extermination. This also means that if neonicotinoids are banned, insect decline will not cease immediately, as it will take years for these substances to be removed from the environment. Therefore, we do not have much time left to turn the page. Any hesitation now can lead to the complete collapse of the ecosystem.