Pesticides Impair Bumblebees’ Ability to Learn Critical Foraging Skills

Bees worldwide face a series of challenges that make their numbers dwindle, from habitat loss and parasite attacks to rising global temperatures and pollution. But a new study adds neonicotinoid pesticides to the list.

A group of British and Canadian researchers found that pesticide exposure alters the way bumblebees forage wild flowers and their ability to learn crucial skills for any pollinator. The changes may lower their chances of survival, researchers believe.

The latest research is the first attempt to analyze pesticides’ impact on bumblebees’ foraging preferences and behavior. The analysis revealed that pesticide-exposed insects tend to dodge wild flowers that have a more complex shape, although they tend to forage pollen and nectar faster than bees not exposed to the chemicals.

Researchers also found that although bumblebees exposed to normal levels of neonicotinoids foraged larger quantities, they took longer to do it than other pollinators. Insecticide-exposed bees were also pickier with the flowers they planned to approach.

Professor Nigel Raine of the University of Guelph in Canada mentioned that bumblebees need to learn a set of foraging skills including tracking flowers, boosting foraging activities, and detecting the most profitable areas to ensure their survival.

Prof. Raine noted that any factor that disturbs their ability to achieve these skills also impairs the “essential pollination services” they bring to humanity.

Other studies had revealed a link between neonicotinoid exposure and persistent neurological changes in honeybees. That research unveiled that the common pesticide negatively impacts the tiny insects’ memory and ability to learn new skills.

Plus, a 2014 study showed that pyrethroid pesticides may make worker bumblebee grow slower. And smaller insects tend to be less efficient in collecting pollen and nectar.

The recent research reveled that bees that were not exposed to the pesticides learned quicker how to handle complex flowers than bumblebees exposed to the chemicals. Surprisingly, neonicotinoid-exposed bees foraged and harvested more pollen and nectar than the control group.

Scientists noted that unaffected bees tend to spend more time and energy in achieving new foraging skills than their pesticide-exposed counterparts. The team also noted that the well-being of pollinators is not only critical to biodiversity, but to global food security, as well.

Bumblebees and other pollinators are critical in maintaining ecosystems healthy globally, the team argued.

A research paper on the findings was published Monday in Functional Ecology.

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