Study Finds “Cocktail” Pesticides Are Killing Bees At A Higher Rate

In many countries across the world, bee numbers are currently threatened. As pollinators, bee populations are incredibly important for ecosystems across the world and our own food supplies. A new analysis of 90 studies has found that “cocktails” of agricultural pesticides can kill twice as many bees. 

The bee population has long been suffering. Threats to their populations are numerous and include habitat loss, climate change, and aspects of agriculture such as chemical pesticides. Many bees also face poor nutrition due to lack of diverse food sources.

A 2021 One Earth study found that “approximately 25% fewer species were found between 2006 and 2015 than before 1990.” The report analyzed public records from the Global Biodiversity Information Facility over 100 years. 

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The report stated that “wild and managed bees are key pollinators, ensuring or enhancing the reproduction of a large fraction of the world’s wild flowering plants and the yield of 85% of all cultivated crops.”

According to National Geographic, research concluded that bees have seen their numbers dwindled – in North America, you are now nearly 50% less likely to see a bumblebee in any given area than you were before 1974.

The study, published by the journal Nature, found that the “cocktails” of agricultural chemicals or pesticides may have a synergistic effect on bee mortality. This means that the total number of bees killed from these combination pesticides is greater than the sum total of deaths caused by all of the separate chemicals individually. 

The study documented 356 total effects from interacting common bee stressors, such as chemicals or parasites. Each study possessed at least two harmful factors to bees. The study then concluded whether the combinations of stressors canceled the other’s effects out, added to the other, or combined to caused even more damage. Researchers found that when bees were exposed to several agrichemicals, the combination had a “synergistic effect” on mortality, while numerous stressors had effects that added to the other.

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Researchers have now argued that these commercial formulas, which contain multiple chemicals in “cocktails,” should require licences. 

Speaking to the BBC, University of Texas at Austin’s Dr Harry Siviter — the lead author of the study — said that “exposure to multiple pesticides is the norm, not the exception.” “If you have a honeybee colony exposed to one pesticide that kills 10% of the bees and another pesticide that kills another 10%, you would expect, if those effects were additive, for 20% of the bees to be killed,” Siviter stated, adding that a “synergistic effect” could produce 30-40% mortality.

“That’s exactly what we found when we looked at the interaction. So we really should consider the interaction between those chemicals. We don’t continue to monitor pesticides once they’re licensed for use, so we’re proposing post-licensing observations. If those pesticides [used in combination] harm bees, that harm is recorded.”

It is unclear why pesticides have such an effect on bee mortality. The study’s abstract explained that “all interactive effects on proxies of fitness, behaviour, parasite load and immune responses were either additive or antagonistic; therefore, the potential mechanisms that drive the observed synergistic interactions for bee mortality remain unclear.”

Other research has indicated that pesticides could weaken a bee’s immune system making them more susceptible to other pathogens or chemicals. Speaking to Popular Science, Elizabeth Nicholls, an ecologist studying bees at the University of Sussex, said that “it also might be that their detoxification pathways might be impaired if they’re being bombarded with lots of chemicals at one time.”

The declining bee population is cause for great concern and has been for some time. In the US, the effects of which can already be seen in threatened crop species such as cherries, blueberries and apples, all of which need be pollination for survival. 


Bumblebees Are Facing Mass Extinction Thanks To Climate Change

Climate change has inflicted its fair share of damage on the planet within the past decade. It’s no surprise that the complete destruction of millions of acres of our natural world has led to a massive increase in endangerment and extinction rates for the species living within those habitats. Just recently over one billion animals fell victim to the devastating bushfires that have been blazing throughout Australia for over three months. 

Obviously, rebuilding what has been lost, and repopulating species that are dwindling in size are top priority for many scientists/environmentalists. One of the biggest concerns comes from the major loss of bumblebee’s throughout North America and Europe specifically. In fact, the likelihood of finding a bumblebee in their traditional habitats within those two continents has declined by a third since the 1970’s. 

Rising global temperatures are causing more species of bumblebee to move further north in both North America and Europe. Bumblebee’s are an obviously essential part of the food chain, as their work benefits all species on Earth. They’re responsible for pollinating fruits, vegetables, and wild plant life that feeds millions of other types of animals and insects. Without their pollination, a myriad of plant species that we use for food will die off, adding even more pressure on scientists who are already trying to combat the world’s growing food shortage issue. 

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“There had been some previous research showing that bumblebee distributions are moving northwards in Europe and North America, as you’d expect with climate change. But this was the first time that we have been able to really tie local extinctions and colonizations of bumble bees to climate change, showing a really clear fingerprint of climate change in the declines that we’ve seen,” Dr. Tim Newbold of University College London (UCL) stated

Global warming, habitat loss, disease, and strong pesticides are the main culprit when it comes to the considerable decline in both range and abundance of bumblebees. There are approximately 250 different species of bumblebees. Researchers and conservationists have done extensive studies of bumblebee population rates. In fact, in a study that specifically looked at more than half a million records of 66 bumblebee species from the 20th century, as well as from the years 2000 to 2014, researchers found that the greatest decrease in population size occurred between the latter years. 

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This isn’t surprising; while climate change has always been an issue, it’s devastating effects have sizeably increased within the 21st century thanks to advances in technology and industrialization. As previously stated, the likelihood of a normal habitat being occupied by bumblebees has dropped 30% more than what the rate was between 1901-1974 (according to the records that were studied).

Since bees are moving further north, in an attempt to move away from the extremely warm weather that has only gotten worse as the years have gone by, the southern areas of both North America and Europe have suffered the greatest loss. These migration patterns do mean that the bees aren’t dying, just inhabiting newer areas, which may seem like a silver lining, however, their survival in more northern areas of the world doesn’t compensate for the loss that the southern areas are enduring. 

Measures such as increasing the margins and buffer strips around agricultural fields that are rich in flowers and wildlife and the preservation of grasslands are deemed effective tools in alleviating the rapid decline in bumblebee species. They can provide bees with forage and help underpin stable populations of pollinators, whose survival is crucial for European food security,” wrote the International Union for Conservation of Nature.

While systematic change is really the only way the planet can reach a turning point in terms of climate change, there are still things we can do at home to at least help our local bumblebees from facing mass extinction. Planting flowers, vegetables and any other type of vegetation in our outdoor living spaces will attract these friendly bees to come and get to work. Remember, bumblebees typically never sting, especially when they’re just left alone, so set out some plants to pollinate and help the world become a little greener, even if it is just in your backyard.