Neonicotinoids are widely used insecticides that are already accused of contributing to the widespread decline of insect populations. But new evidence shows that it may also harm deer, birds, rabbits, and other mammals.

Cornfield
(Photo: Photo by Monika Baumgartner from Pexels)

What are Neonics?

Chemically related to nicotine, neonics were developed in the 1990s as an alternative to toxic, long-lasting farm chemicals. Today, these are the most widely used pesticides globally, affecting leafhoppers, aphids, beetles, borers, and a wide range of worms. 

Spread as coatings on seeds of crops covering roughly 150 million acres in the U.S. neonics are taken up by various plant parts such as nectar, pollen, fruit, stems, leaves, and roots. As insects chew on or suck their preferred portions, they then curl and die.

According to the Department of Entomology of Penn State, synthetic insecticides have rapidly grown in use in North America that estimated 90 million acres of corn are annually dosed with neonics. 

However, history shows that a broad-spectrum pesticide tends to have unintentional consequences. Scores of studies show that neonics and habitat destruction, and climate change contribute to the steady decline of insect populations.


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The Dangers of Neonics as Insecticides

Evidence of harm due to the use of neonics is strong enough that the European Union has banned three popular neonics for outdoor use. While the U.S hasn't taken decisive action, it is clear that bees and other beneficial insects aren't the only animals at risk.

In the past several years, numerous scientists have found that the crops take in only 5% of neonic seed coatings. The rest either wash or wear off. The chemicals accumulate in the soil and waterways, where an even larger range of wildlife is exposed.  

Growing evidence shows that compounds tailored for invertebrates pose a threat to fish, birds, and mammals.

Researchers in Canada show that the consumption of at least four imidacloprid-treated canola seeds in three days can greatly interfere with a sparrow's ability to migrate.

Lab studies report various evidence on the exposure of neonics that harm vertebrate animals. It is known to reduce sperm production, increase abortion and skeletal abnormalities in rats, suppress the immune response in mice, and suppress sexual function in Italian male wall lizards. 

In addition, it also impairs the mobility of tadpoles, increases miscarriage and premature births in rabbits, and reduces survival rates of red-legged partridges in both chicks and adults.

Does Neonics Harm Humans?

Humans are unconsciously exposed to neonics when we accidentally inhale or touch surfaces with the coating, especially when applying flea-and-tick treatments for pets.

Over the past decade, the U.S Environmental Protection Agency reports roughly 1,600 cases of imidacloprid poisoning in humans. Humans also consume food treated with neonics. 

A study in 2019 by the National Institutes of Health showed that 49.1% of 3,038 human urine samples had traces of neonics.

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