Neonicotinoids
Insect pollination is a vital ecosystem service that maintains biodiversity and sustains agricultural crop yields. ~ English animal ecologists Richard Gill & Nigel Raine
While DDT is ostensibly banned, it is only one of many in the 1st generation of synthetic pesticides, several of which remain in use. In succeeding generations of pesticides, chemists thought themselves clever by synthesizing variants of molecules that plants themselves produce to ward off their pests. An obvious candidate was nicotine. Neonicotinoids were developed in the late 1980s.
Neonicotinoids mimic the action of neurotransmitters. In doing so, they continuously stimulate neurons, leading ultimately to death of target invertebrates. Like virtually all insecticides, they can also have lethal and sublethal impacts on non-target organisms, including insect predators and vertebrates. ~ Dutch entomologist and ecologist Noa Simon-Delso et al
Neonicotinoids are quite good at killing insects. In most instances it takes a few mere molecules per billion, equivalent to a few drops in a swimming pool of water.
Neonicotinoids found favor for their supposed specificity: they were not as lethal to larger animals as insects. Neonicotinoids became wildly popular.
Being water soluble, neonicotinoids leach into ponds, ditches, and streams and contaminate groundwater. Waterways with neonicotinoids have depleted insect abundance and diversity. ~ Dutch biologist Maarten van Lexmond et al
There is strong evidence that soils, waterways, and plants in agricultural environments and neighboring areas are contaminated with neonicotinoids and their metabolites. ~ French ecologist and chemist Jean-Marc Bonmatin et al
Neonicotinoids can persist for years in soils, and so cause environmental concentrations to build up. ~ Maarten van Lexmond et al
Besides spraying, neonicotinoids are slathered on seeds to prevent their being eaten by bugs. Beyond killing pollinating insects, severely polluting seed-eating birds, and other environmental degradation, that tactic is useless.
Neonicotinoids otherwise have had quite an impact. They pummel the primary pollinators upon which all crops rely: bees. Honeybee colonies suffered terribly after the introduction of neonicotinoids, yet it took scientists decades to ascertain the obvious: insecticides hurt insects.
Neonicotinoids are highly likely to be responsible for triggering ‘colony collapse disorder’ in honeybee hives that were healthy. ~ Chinese American ecologist Chensheng Lu
Repeated exposure to even low doses of neonicotinoids befuddles bees, enfeebling their foraging. This impairs their pollination services, which are crucial to healthy ecosystem functioning.
Insecticides have a significant negative impact on bee learning and memory. This occurs even at the low levels of pesticides that bees would routinely encounter in the field. ~ English biologist Harry Siviter
Still the lesson has yet to sink in. Neonicotinoids continue to be massively employed – business as usual until a silent spring, as Rachel Carson feared.
It is not clear, based on current research, whether pesticide exposure is a major factor associated with US honeybee health declines. ~ US Department of Agriculture in 2012
As aforementioned, neonicotinoids are merely more toxic to insects than mammals. Unsurprisingly, these pesticides damage fish, avian, and mammalian nervous systems too.
Although vertebrates are less susceptible than arthropods, consumption of small numbers of dressed seeds offers a potential route for direct mortality in granivorous birds and mammals, for such birds need to eat only a few spilt seeds to receive a lethal dose. Lower doses lead to a range of symptoms including lethargy, reduced fecundity, and impaired immune function. ~ Maarten van Lexmond et al
Early exposure to pesticides is especially destructive, causing developmental detriments, including autism in children. Autism has surged in the US in the 21st century owing to pollution. The state with largest leap is New Jersey, which is heavily polluted, due partly to hosting many toxic chemical plants.
Far from protecting food production, the use of neonicotinoid insecticides is threatening the very infrastructure which enables it. ~ Jean-Marc Bonmatin
Pesticides simply are not ecologically sensible. Their effects are more damaging, and widespread, than has been assumed. Honeybees and other pollinators are poisoned by pesticides on plants that were never sprayed.
In the past, we underestimated the risks of widely used pesticides. ~ Chinese ecologist Guangming Zeng et al
