From honey bees to dragonflies, populations of insects worldwide are nosediving towards a “catastrophic collapse” – and the US is no exception. While the cause of this decline is often complex and hazy, scientists have managed to find an undeniable contributing factor lurking in agricultural landscapes across the US.
A major new study has suggested that the oncoming “insect apocalypse” in the US could be a result of land becoming 48 times more toxic to insects than it was 25 years ago, primarily due to neonicotinoid pesticides.
“It is alarming that US agriculture has become so much more toxic to insect life in the past two decades,” Kendra Klein, PhD, study co-author and senior staff scientist at Friends of the Earth, who helped to fund the study, said in a statement.
“We need to phase out neonicotinoid pesticides to protect bees and other insects that are critical to biodiversity and the farms that feed us."
Reporting in the journal PLOS ONE, a team of toxicologists, biologists, and pesticide experts took a look at insecticide levels in agricultural lands and the surrounding areas between 1992 and 2014, while also accounting for their level of toxicity and how long the chemicals persist in the environment.
By their workings, the acute toxicity loading of insecticides in agricultural land in the US was 48 times higher in 2014 compared to 1992. The big jump in land toxicity started in the mid-2000s, a time when neonicotinoids first started being used to coat the seeds of commodity crops like corn and soy.
The study also highlights that neonicotinoids represented 61 to nearly 99 percent of the total toxicity. Three neonicotinoids stood out in particular: imidacloprid and clothianidin, manufactured by Bayer, and thiamethoxam, manufactured by Syngenta-ChemChina.
Neonicotinoids, a group of synthetic insecticides that are chemically related to nicotine, have come under a lot of heat in recent decades over their effects on the surrounding environment, namely on honey bees but also birds, aquatic invertebrates, and other wildlife. As this new study affirms, neonicotinoids aren't just more toxic to insects than other pesticides, they are also far more persistent in the environment, often killing insects for months to years after application.
Even beyond the US, a meta-analysis study has shown that 40 percent of insect species could face extinction in the coming decades. While climate change was a notable factor, the researchers argued that the “root cause” of the problem is the intensification of agriculture over the past six decades, entailing pollution, loss of habitat, and increasingly relentless use of synthetic pesticides.