Environmental threats stress bumblebee queens

Environmental threats are putting bumblebee queens under pressure, according to new research. Exposure to insecticides and a poor diet negatively impacted the health and work of the already dwindling pollinator group.

Once bumblebee queens emerge from hibernation in the spring, they must make nests, lay eggs and keep their larvae warm and fed, with nests of up to 400 workers established from the work of a single queen.

However, the queens also face environmental challenges, according to new research from the University of California.

The research team found that exposure to a widely used insecticide and a poor diet negatively impacted bumblebee queens’ health and work, which could have devastating consequences for the already dwindling pollinator group.

“Queens are probably already a bottleneck for bumblebee population dynamics,” explained study leader Hollis Woodard in a statement. “If a queen dies because of exposure to manmade stressors, then a nest full of hundreds of important pollinators simply won’t exist.”

Bumblebees are workhorses of the insect pollinator world, with a range of crops depending on their pollinator services.

Previous studies have implicated insecticides, including the widely used neonicotinoids, with a decline in pollinators.

The research team showed that bumblebee queens were far less active and six times more likely to die during sustained exposure to the pesticide. The surviving exposed bees also produced only a third of the eggs and a fourth of the larvae of untreated queens.

Another stressor bumblebees face is declining floral diversity, driven by agricultural land use and other global changes. While the effects of a single-source pollen diet were overshadowed by the effects of pesticide exposure, according to the statement, a monofloral pollen diet alone was sufficient to negatively affect bumblebee brood production.

Photo credit: Martin Cooper/ CC BY 2.0

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