A new study which looks at bee colony deaths has shown for the first time that even pesticides marked as safe for use around bees are implicated in the die-offs of bee colonies.
Researchers at The University of Maryland applied a different criteria to the latest study. Usually pesticide studies look at each pesticide in turn and declare them safe or otherwise but this time the researchers looked at the effects of real-world pesticide exposures within a colony to see the effects the whole cocktail can have on the bees, which allows researchers to effectively test the cumulative effect on the bees.
This could be a game-changer as assessing the overall effect has proven beyond a doubt that even ‘bee-safe’ substances have a major effect on the health of the colony and in some cases these effects can determine whether the colony lives or dies.
The study was published in Nature on September 15th. Lead author Dennis vanEngelsdorp assistant professor of entomology at UMD said:
“Our results fly in the face of one of the basic tenets of toxicology: that the dose makes the poison. We found that the number of different compounds was highly predictive of colony death, which suggests that the addition of more compounds somehow overwhelms the bees’ ability to detoxify themselves.”
The researchers followed 91 colonies for a full season. The colonies began the season in Florida and moved up the east Coast pollinating different crops along their route.
A massive 93 different pesticide compounds found their way into the colonies over the course of the season. These compounds were found in the bee’s wax, in bee bread, a processed bee pollen, and in the bodies of nurse bees.
The researchers documented the bees at every ‘stop’ they made and assessed the same criteria at each stop and these included the total number of pesticides and the hazards the bees face from the cumulative totals of pesticides.
It was found that every single parameter they checked increased the probability of colony death or queen failure. Up to 20 residue samples of pesticides were found in some colonies.
The study also implicated fungicides which seemed to have more effect on bee larvae and had toxic effects on the bees in the field.
“We were surprised to find such an abundance of fungicides inside the hives, but it was even more surprising to find that fungicides are linked to imminent colony mortality,” said Kirsten Traynor, a postdoctoral researcher in entomology at UMD and lead author on the study. “These compounds have long been thought to be safe for bees. We’re seeing them at higher doses than the chemicals beekeepers apply directly to the colonies to control varroa mites. So that is particularly concerning.” (source)
Surprisingly the team did not find the amount of neonictinoids that they expected. These compounds, derived from nicotine are used globally and have seen a huge amount of backlash over their involvement in colony deaths.
“We just did not find neonicotinoids in the colonies,” vanEngelsdorp explained. “There were some trace residues of neonicotinoids in a few samples, but not nearly on par with other compounds. However, it’s possible we did not test the right matrix — we did not test nectar, for example — or that the product breaks down faster than others in the collection process or that neonicotinoids are simply not very prevalent when crops are flowering.”
Although the study was published just last month the data was collected some time before and the team are aware that some practices have chanced since the data was collected. They feel the study is still valid to what is happening to colonies around the globe and particularly in the United States.
The death of the queen and the inability to produce a new one will ultimately result in the death of the colony. The study shows without doubt that those colonies with very low overall pesticide contamination shown in the beeswax had no incidences of queen deaths. Many beekeepers replace the queens in their colony every season in the hope they will survive, even such a drastic measure sees many queens that don’t survive a single season.
“We have to figure out ways to reduce the amount of products that bees are exposed to while still helping farmers produce their crops,” vanEngelsdorp said. “This will require careful examination of spray plans, to make sure we only use the products we need, when we need them, in order to reduce the number of products bees are exposed to while pollinating different crops.” (source)
Bees are essential to life. wholesale spraying of Naled was recently linked to the death of 2.5 million bees in once incident. You would think that the knowledge that the demise of the bees could lead to widespread starvation companies spraying these products would think twice – but that doesn’t seem to be the case.
Even testing by the companies that produce these mass killers prove that there is a link between bee deaths and their products but still they continue to pedal their poisons. It has to stop, not just to save the bees, but to save the humans that depend on them.
Kirsten S. Traynor, Jeffery S. Pettis, David R. Tarpy, Christopher A. Mullin, James L. Frazier, Maryann Frazier, Dennis vanEngelsdorp. In-hive Pesticide Exposome: Assessing risks to migratory honey bees from in-hive pesticide contamination in the Eastern United States. Scientific Reports, 2016; 6: 33207 DOI: 10.1038/srep33207