Bee collecting pollen and eating nectar on a pink flower

Study: Pesticides Are Creating Pollination Problems and Killing Bees

Neonicotinoid pesticides, which are widely used in intensive agricultural operations, have been implicated in the decline of bees, particularly in commercially bred species like honeybees and bumblebees.

August 30, 2016 | Source: Mercola.com | by Dr. Joseph Mercola

Neonicotinoid pesticides, which are widely used in intensive agricultural operations, have been implicated in the decline of bees, particularly in commercially bred species like honeybees and bumblebees.

New research published in Nature Communications has now shown these chemicals are leading to long-term population changes in wild bees as well.1

The study involved 18 years of U.K. wild bee distribution data for 62 species, which were compared to amounts of neonicotinoid use in oilseed rape, a crop grown to produce canola oil. The researchers found evidence of increased wild bee population extinction rates in response to neonicotinoid seed treatment.

While bees that forage on oilseed rape have historically benefited from its availability, according to the researchers, once the crops are treated with neonicotinoids (as up to 85 percent of England’s oilseed rape crops are) they have detrimental impacts on the bees.

In fact, wild foraging bees were three times more likely to be negatively affected by exposure to neonicotinoids than non-crop foragers. Overall, about 50 percent of the total decline in wild bees was linked to the pesticides.2

It’s being described as the “first good evidence” that the widespread use of neonicotinoids is harming wild bees at the population level.3 The authors explained:4

“Our results suggest that sub-lethal effects of neonicotinoids could scale up to cause losses of bee biodiversity. Restrictions on neonicotinoid use may reduce population declines.”

Butterfly Declines Also Linked to Neonicotinoids

The evidence continues to build that the use of neonicotinoids could be putting the future of pollinators in jeopardy. In addition to honeybees, bumblebees and wild bees, the chemicals have been implicated in declines of butterflies in Northern California.

Researchers from the University of Nevada tracked 67 butterfly species at four locations for at least 20 years.5 At each site, declines in the number of butterfly species were most closely linked to increased used of neonicotinoids, even more so than other potential factors in butterfly declines, like land development.6

Past studies have shown similarly alarming trends in relation to neonicotinoid usage. In England, for instance, butterfly species declined by 58 percent on farmed land between 2000 and 2009.7

Further, a study in the journal PeerJ found 15 of 17 butterfly species showed negative associations with neonicotinoids. According to the researchers:8

“The declines in butterflies have largely occurred in England, where neonicotinoid usage is at its highest. In Scotland, where neonicotinoid usage is comparatively low, butterfly numbers are stable.”

How Do Neonicotionids Harm Bees?

The majority of soybean, corn, canola and sunflower seeds planted in the U.S. are coated with neonicotinoid pesticides. The chemicals, which are produced by Bayer and Syngenta, travel systemically through the plants and kill insects that munch on their roots and leaves.

When treated with neonicotinoids, all parts of the plant become potentially toxic to insects. Neonicotinoids are powerful neurotoxins and are quite effective at killing the pests, but they’re also harmful to non-target pests, namely pollinators such as bees and butterflies.

This occurs because the pesticides are taken up through the plant's vascular system as it grows and, as a result, the chemical is expressed in the pollen and nectar of the plant.

The effects of different neonicotinoids were long regarded as interchangeable, but one study showed each may affect bees differently. Bayer’s imidacloprid was found to cut the number of egg-containing brood cells by 46 percent.

Syngenta’s thiamethoxam, on the other hand, decreased the number of live bees by 38 percent.

Clothianidin, another neonicotinoid made by Bayer, had the curious effect of increasing the number of queens produced, which the researchers noted could potentially backfire if, “say, all those queens turned out to be infertile.”9,10

Lead researcher Dr. Christopher Connolly of the University of Dundee told The Guardian, “I think there is sufficient evidence for a ban on imidacloprid and thiamethoxam … ”11

Yet, even in response to the U.K. study showing neonicotinoids are linked to declines in wild bee populations, Bayer is making excuses.

One representative for Bayer Crop Science in the U.K. said it’s more likely that intensive agriculture, and not the use of neonicotinoids, per se, is causing issues with pollinators (even though the two go hand-in-hand).12

Fortunately, the European Union (EU) put a temporary ban on the use of neonicotinoids, beginning December 1, 2013 (and still in force today), to study their involvement with bee declines.