Honeybees Exposed To Real-World Levels Of Neonicotinoids Die Early, Damaging Colony Health, Research Finds

Honeybees that are exposed to field-realistic (real-world, in other words) levels of neonicotinoid pesticides die earlier than those that are not — thereby reducing overall colony health — according to a new study led by York University.

“A worker honeybee has been fitted with a RFID on its back so researchers can record when it enters and leaves the colony.” Credit: York University Professor Amro Zayed

The findings relate to both worker bees and queen bees, interestingly. But, perhaps even more interesting, is that the neonicotinoid-contaminated pollen collected by the honeybees came not from crops grown with neonicotinoids, but from plants growing in areas adjacent to those crops.

This isn’t actually too surprising, though, as the nature of monoculture means that if bees were to rely solely on crops, then they would starve much of the time, because of the lack of availability of food except during narrow windows of time.

While there’s been much earlier research showing the negative effects of neonicotinoids on honeybees, a common criticism of much of it is that it was “unrealistic” — that is, that it didn’t relate to real-world exposure levels. The new work was intended to address this criticism.

“This debate about field realistic exposure has been going on for a long time,” stated York U biology Professor Amro Zayed of the Faculty of Science. “We needed season-long monitoring of neonics in bee colonies to determine the typical exposure scenarios that occur in the field, which we have now done.”

The work involved studying honeybee colonies in 5 different apiaries near maize/corn grown with neonicotinoid-treated seeds, and 6 apiaries located far from agriculture. The colonies were studied — that is to say, sampled and tested for pesticides — from early May to September.

“Honeybee colonies near corn were exposed to neonicotinoids for three to four months. That is most of the active bee season in temperate North America,” commented York U PhD student Nadia Tsvetkov.

As noted above, though, the neonicotinoid contaminated pollen collected by the honeybees didn’t come from maize/corn or from soybeans — the two crops grown extensively in the region from neonicotinoid treated seeds.

“This indicates that neonicotinoids, which are water soluble, spill over from agricultural fields into the surrounding environment, where they are taken up by other plants that are very attractive to bees,” continued Tsvetkov.

The press release provides more: “The researchers then chronically fed colonies with an artificial pollen supplement containing progressively smaller amounts of the most commonly used neonicotinoid in Ontario, clothianidin, over a 12-week period. The experiment mimicked what would occur naturally in the field.

“The worker bees exposed to the treated pollen during the first nine days of life had their lifespans cut short by 23 per cent. Colonies that were exposed to treated pollen were unable to maintain a healthy laying queen, and had poor hygiene.

“We found that realistic exposure to neonicotinoids near corn fields reduces the health of honey bee colonies,” concluded Tsvetkov.

The research also revealed that when a commonly used fungicide known as boscalid is present alongside neonicotinoids that both become more dangerous.

“The effect of neonicotinoids on honey bees quickly turns from bad to worse when you add the fungicide boscalid to the mix,” explained Professor Valérie Fournier of Laval University, a collaborator on the new research. “The researchers found that field realistic levels of boscalid can make neonicotinoids twice as toxic to honeybees.”

There are of course a number of reasons that bee populations have been experiencing significant diebacks in recent years other than just neonicotinoids, it should noted — it’s not simply that there is one “problem” that can be solved, but that the whole industrial agricultural system itself is systematically destroying wild and “domesticated” bee populations.

These other factors include: the nature of monoculture itself (lots of bee food at certain times and none at others, limited bee-food variety and the nutritional problems that accompany that, etc.); the great stress that is placed on bees as a result of diminishing biodiversity; the maximization of profit at the expense of colony health (the replacement of all stored honey with corn syrup or sugar rather than just some of it, shipping over long distances, etc.).

All in all though, it seems that it can safely be said at this point that neonicotinoid pesticides are having a very negative effect on bees, whether wild or domesticated, and also on the wider environment.

While this new research probably doesn’t come across as being overtly “clean tech” oriented, it’s something that should be covered here anyways, in my opinion, owing to the reality that the industrial system as a whole is entirely dependent upon agriculture — and more generally, upon the natural environment. That’s something that is easy to forget. If honeybee numbers, and pollinator numbers in general, continue falling as rapidly as they have in recent years, then agricultural yields stand to drop enormously — something that would undermine nearly part of the modern world.

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