What emerges from the two studies is a picture of a global agricultural landscape heavily contaminated with persistent toxins that are destroying populations of wild bees and harming captive honeybee health.
The CEH Study (Woodcock et al. 2017) was brokered by Defra and funded by Bayer and Syngenta, and has been touted by many as the study that will provide conclusive evidence about the role of neonicotinoids in bee decline. It is the first properly replicated winter sown Oilseed rape field study, with 33 sites examined in the UK, Germany and Hungary. However, the study was seriously limited by the single exposure source examined – pollen and nectar from the Oilseed rape. In real life bees are also exposed to high concentrations of neonicotinoids in widely dispersing dust produced during the planting of treated seeds and the ploughing of land, and through pollen and nectar in wildflowers near arable fields; which can contain higher levels of neonicotinoids than in the crop flowers.
Despite the CEH Study only looking at one narrow source of bee poisoning the authors still found that honeybees and wild bees were all significantly impacted, with big reductions in honeybee colony size and reduced reproduction rates in wild bees.
The second paper, a Canadian study on neonicotinoid treated maize (Tsvetkov et al. 2017), found that neonicotinoids killed honeybee workers, reduced bee hygiene activity and resulted in queenless hives. The bees were not getting poisoned primarily by crop pollen and nectar however, the main route of acute exposure was neonicotinoid contaminated dust and the biggest exposure throughout the year was from neonicotinoids in wild flowers.
The Canadian study also found that the common fungicide boscalid almost doubled the toxicity of neonicotinoids to bees. This is significant because a recent paper showed that 70% of the plants that people buy from garden centres to help garden bees contain neonicotinoids, and 48% also contain boscalid (Lentola et al. 2017). This suggests that gardeners may be unknowingly poisoning pollinators in their efforts to try to help them, a factor that may be associated with recent declines in numbers of urban butterflies (Dennis et al. 2017).
“The horror story is clear, we have contaminated our land and water with persistent neonicotinoid pesticides, already 40% of UK wild bees have been effectively exterminated across large parts of their range. We are calling on Michael Gove to review the Government’s position and to get fully behind international efforts to secure a global ban on the use of these toxins; let’s get them out of our meadows, streams and gardens and give our bees, butterflies and birds a chance to recover.” Said Matt Shardlow, Buglife CEO.