Study investigates bee colony population declines
In recent years, concern has grown regarding the use of neonicotinoid pesticides and their impacts on bees, as large colonies of bee populations have begun dying off in rapid fashion. A [link url=”http://www.nature.com/articles/ncomms12459″ title=”new study released in August”] highlighted results of 18 years of data collection and bee colony observation in England regarding the use of neonicotinoid pesticides and their effects on bee colonies.
Global wild bee declines from various adverse practices, including habitat loss, disease, climate change, and pesticide use, has also sparked concern over future food crops. Since bees and other insects pollinate approximately 9.5 percent of food sources around the world, protecting them from harm is paramount to avoid a major loss in biodiversity and any possible resulting food shortages.
Bee populations adversely affected
Prior to this study, which covered an extended period of time, most evidence regarding the detrimental impacts on bees from neonicotinoids came from shorter and smaller-scale studies that identified adverse affects on bee colonies, including a drop in the queen’s production (B. terrestris) by 85 percent, and reduced reproduction in the O. bicornis by 50 percent. Longer scale studies have also recorded significantly reduced growth rates in colonies, causing a moratorium on the use of the pesticides in the European Union in 2013, although exemptions were granted in the United Kingdom.
The new, longer study was conducted in England on oilseed rape crops, a crop that is widely produced and provides the most active forage for bees, with more than 8 million hectares (ha) of coverage alone in the European Union. The study grouped bees according to oilseed rape foragers and non-foragers, with results clearly depicting a negative impact on oilseed rape foragers that was three times greater than for the non-foragers.
Consequently, over the length of the study it showed a ‘scaled-up’ decline in wild bee populations that foraged on the oilseed rape crops that were treated with neonicotinoids. Further assessment showed a greater than 20 percent loss in various species as a result of neonicotinoid use.
Neonicotinoids linked to bee colony losses
Researchers concluded that evidence from the study strongly suggests that the use of neonicotinoids has contributed to the decline of wild bee species, and that the loss is not made up by the expansion of the oilseed rape crop for foraging through the use of the pesticide. They also suggested that other contributing factors, including environmental pressures, climate change, and land use, may also affect wild bee populations.
In light of the findings, the researchers recommend a continuation of the moratorium on the use of the neonicotinoids, and suggest that with the absence of this pesticide, “that the recovery of at least some wild bee species may be relatively rapid.”
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