Throughout the Northern Hemisphere beekeepers have struggled to maintain adequate numbers of honeybee colonies for crop pollination and honey production due to dramatic increases in colony deaths each year. Recent surveys of beekeepers suggest that poor queen health is an important reason for these losses, but why queen health is being affected is not understood.
A research team from Bern, Switzerland and Wolfville, Canada, has found that honeybee queens, which are crucial to colony functioning, are severely affected by two neonicotinoid insecticides, thiamethoxam and clothianidin. In 2013, governments in Europe moved to partially restrict the use of these neonicotinoids while further risk assessments could be performed. The province of Ontario, Canada, followed suit in 2015. This is the first study to investigate the effects of neonicotinoids on honeybee queens. Its findings suggest that these insecticides may be contributing to bee colony mortality by affecting queen health, and it further strengthens calls for more thorough environmental risk assessments of these pesticides to protect bees and other beneficial organisms.
The observation that honeybee queens are highly vulnerable to these common neonicotinoid pesticides is worrisome, but not surprising, says senior author Laurent Gauthier. The study shows profound effects on queen physiology, anatomy and overall reproductive success. The queen, as the sole egg-layer and the primary source of colony cohesion, is the most important individual in the colony; without her the colony will eventually fail to function.
This article appears in the December 2015 issue of Acres U.S.A.