“Pollinator summits” in Minnesota and elsewhere during the past year have showcased discussions among beekeepers, landscapers, farmers and government agencies on how to better protect honeybees, butterflies, birds and bats that pollinate flowers, crops and other plants.
European colonists brought domesticated honeybees to North America nearly 400 years ago. Additional species were introduced over the following centuries. Of all pollinators, the honeybees do the truly heavy lifting.
In recent years, higher-than-normal wintertime deaths have generated understandable concerns about “colony collapse disorder,” bee extinctions, a potential “bee-pocalypse” and the “plight of the bumblebee.” Some have blamed the high death rate on pesticides, especially neonicotinoids that are used primarily as seed coatings and, to a lesser degree, in other applications.
However, most people are unaware of some important facts that need to be included in pollinator discussions, if we are to get the science and policies right.
For one thing, reports of major, unexplained bee disappearances date back at least to 940 A.D. in Ireland. The vexing problem is nothing new.
Second, actual field studies of bee populations in association with extensive neonicotinoid use in canola and corn production in Canada and elsewhere show no observable adverse effects on honeybee colonies from exposure to properly applied neonic pesticides. Laboratory studies that have found harm almost invariably involves overdosing bees with the insecticides being tested — and that is hardly an accurate measure of the actual risk to bee colonies under field-realistic conditions.
In fact, Department of Agriculture data show that U.S. bee populations have actually increased from 2.6 million colonies in 2000 to 2.7 million in 2014. That’s 100,000 more colonies and tens of millions more bees, just in the United States, over the same period that neonic use was increasing dramatically.
“Stats Canada” data show the number of Canadian colonies increased by 17 percent between 2009 and 2014, and colony totals for 2014 and 2015 are the highest in three decades. European and global numbers are also rising.
Obviously, there is no bee-pocalypse. Honey bee populations have been holding steady or rising as neonic use grew exponentially over the last two decades. However, bees clearly have faced problems in recent years, and beekeepers, entomologists and agricultural experts have worked hard to figure out why. The summits have been a part of that work.
Although the mistake has often been made in news stories, it is important not to confuse over winter losses — which have been higher than 30 percent in some recent years — with overall population declines. That’s because bee numbers quickly rebound in the spring, when foraging and breeding resume.
Research increasingly points to the invasive “Varroa destructor” mite, a nasty parasite that arrived in the late 1980s from Asia. It is probably the chief culprit in bees’ health problems today, and one that is more widely epidemic than experts previously believed.
The mites transmit over a dozen viruses and other diseases as they feed like mosquitoes on honeybees’ hemolymph or “bee blood.” While parasitizing bees, the mites also secrete an enzyme that compromises the bee’s immune system and makes the effects of transmitted diseases even more virulent.
Mite-infested hives become much more susceptible to other diseases, especially when beekeepers bring hundreds of thousands of hives from across the United States to pollinate California’s almond groves each winter. There the bees can share their parasites and diseases, including Varroas, the Nosema ceranae gut fungus, parasitic phorid flies, tobacco ringspot virus and deformed wing virus.
Interestingly, as these results came in, anti-neonic scientists presented exotic, new indirect mechanisms by which neonics “could” be harming bees.
One claimed chronic exposure to Thiamethoxam caused bumblebees to learn foraging tasks more slowly, forget what they learned more quickly, and thus become less efficient in feeding their colony. Another claimed honeybees foraging on neonic-treated fields disappeared faster than normal.
However, no matter what effects these researchers have been able to hypothesize or even demonstrate in laboratories regarding effects on individual bees, no observable adverse effects have been found on bees at the colony level, under field-realistic levels of neonic exposure. That has been the case even when bees are foraging in neonic-treated canola and other crops.
Ironically, the most prevalent pesticides found in beehives today are those used by beekeepers themselves to combat Varroa mites — trying to “kill bugs on bugs.” Those chemicals do work, to a point. But they can turn beehives into toxic chemical swamps. Careful selection and application are absolutely essential.
These complex considerations suggest that regulators should not ban or restrict neonicotinoids.
For one thing, the activists’ appeals to do so are based on a misdiagnosis of honeybee problems, exotic unproven theories and groundless fear-mongering. Second, “the cure would be worse than the disease,” if a neonic ban forced growers to return to older pesticides that actually are harmful to bees.
After all, the goal of modern science is to solve problems without creating worse consequences.
This article originally appeared in The Washington Times