In 2017 the largest in-the-field study on nionicotinoids and bees was undertaken. “Puzzling” results were reported for honeybees.
Yesterday we told you about new research into the effects of tiny amounts of nionicotinoids on bumblebee brooding habits. An expert quoted by the ABC indicated that all bees are quite nuerobiologically similar, but the jury is still out on whether neonics affect honeybees.
Mid-last year, the largest field study yet reported its long-awaited results. Nature reports that scientists from the Centre for Ecology and Hydrology (CEH) in the UK put honeybees, mason bees (Osmia bicornis) and bumblebees in 33 oilseed-rape fields. There were fields in the United Kingdom, Germany and Hungary. They used either neonicotinoid or neonicotinoid-free pesticide-treated seeds.
Unsurprisingly, bumblebees and mason bees fared less well with increased exposure to neonics. But the honeybee picture was more complicated. While in some cases neonics seemed to affect bee health, in others they didn’t. In the United Kingdom and Hungary, neonics seemed to reduce worker-bee numbers in honeybee hives. Also in Hungary, researchers saw fewer egg cells in these hives, a sign of reduced reproductive success. But in Germany the honeybee hives exposed to neonics had more egg cells, “a puzzling result” according to Nature.
Overall, the study concluded that neonicotinoids reduced bees’ ability to establish new colonies after winter. The journal editor’s summary of the paper came under the headline: “Damage confirmed”. And this is where the drama ensued – the agrochemical firms that funded the study did not agree. They interpreted the data differently, and made this clear to the press.
If anything, the ‘mixed’ results of research tells us that we are dealing with a complex picture. But with honeybee populations declining in many parts of the world, one can see merit in taking precautionary action. Reportedly, scientists have hailed the EU ban on the chemicals. If you have a bit of time, the Nature article provides a long-form overview of the research, history and debate.
