Neonicotinoid exposure affects social behavior of bees

As most of us have heard repeatedly over the past 10+ years, something is affecting pollinator-bee survival. This is clearly a topic for these GEITP pages (i.e. gene-environment interactions). Bees are critical contributors to agricultural crop production — as well as to the life cycle of most flowering plant species on the planet. Yet, these essential ecosystem-service providers appear to be in decline. Widespread pesticide use, associated with increasingly intensive agriculture, is one of several (likely interacting) factors that contribute to these concerns about the drop in number of pollinator insects.

Although insecticide applications are targeted at controlling pests, their use can have unintended impacts on beneficial insects, including bees. As the most widely used class of insecticides in the world today, neonicotinoids have come under considerable scrutiny, following concerns around their nontarget impacts on bees. Authors [see attached article and editorial] identified how exposure to one of these neurotoxic insecticides can adversely affect individual bumblebees and social dynamics within their colony.

Using an innovative automated robotic platform, authors continuously monitored the behavior of uniquely identified workers inside multiple bumblebee colonies, each housed in a specially-constructed nest box attached to a foraging chamber. They found that “environmentally realistic” exposure to the neonicotinoid imidacloprid [chemical structure seems likely to interact by binding covalently with endogenous compounds],

Imidacloprid.png

dissolved in artificial nectar collected from the foraging chamber, resulted in measurable behavioral changes in workers inside the nest.

The bumblebees were less active, less likely to feed and care for larvae (i.e. to act as nurses), and more likely to be found toward the nest periphery, when compared with worker bees in control colonies. Curiously, these changes were more pronounced at night, which might reflect the bees’ daily patterns in pesticide consumption and/or metabolic detoxication of this chemical.

DwN

Science 9 Nov 2o18; 362: 683–686 [article] & pp 643–644 [editorial]

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