A largely used pesticide's detrimental effects on bees has been controversial with manufacturing companies claiming that previous studies had been conducted in artificial conditions. The largest field study ever conducted on neonicotinoid pesticides (neonics) show that they are, in fact, harmful to bees.
However, the detrimental effects that were observed in most countries were less apparent in German bee colonies.
Largest Field Study
A large study that spans across three European countries monitored 33 sites in the United Kingdom, Germany, and Hungary, focusing on honeybees and two types of wild bees, the Bombus terrestris and Osmia bicornis.
What researchers did was to monitor the 33 sites in the three countries, all strategically placed near large fields of canola. Some fields were treated with a combination of neonic pesticides and a standard fungicide, while the other fields were treated with the fungicide but without the neonic pesticide.
What researchers found was that the bee populations that were placed close to fields treated with neonic pesticides showed lower reproductive success and slimmer survival chances in the winter.
Specifically, the bee colonies in Hungary showed a 24 percent decrease in colony size, while colonies in the UK showed generally low colony survival rates, but were lowest in areas where bees fed on the clothianidin treated oilseed rape the previous year.
However, the bee colonies in Germany showed no specific detrimental effects even with neonic exposure, and in fact yielded more eggs and more larvae, and were practically free from parasites.
Opposing Results
Results of the study published in the journal Science are quite interesting as they showed detrimental effects on the bees in the United Kingdom and Hungary, and seemingly opposite results in the colonies in Germany.
Researchers aren't exactly stumped by these results, and in fact believe that this discrepancy could explain the inconsistent results from previous studies. Apart from possibly having other unknown factors, which contribute to bee colony health, they believe that the difference in results may lie in the bees' environment.
In the UK and in Hungary, about 40 to 50 percent of the colony's pollen was collected from canola, while only 10 percent of the pollen in German colonies was collected from the crop. Because of this, researchers believe that a large factor in the bees' vulnerability is their dependency on pesticide-treated crops.
In the UK and in Hungary where the wildflower population has gone down due to modern farming, the bees' dependence on pesticide-treated crops is higher, whereas the German colonies are likely to be exposed to more diverse food sources.
It is perhaps worth noting that this research was partly funded by pesticide manufacturers Bayer and Syngenta. Even so, the researchers were said to have operated independently, and because of the results, they believe that the case on neonics effect on the bee population remains inconclusive and requires further research.
