Early to wake is neither healthy nor wise for bumblebees

Climate change affecting hibernation for the pollinators in North America, finds study; impact on human agriculture;;
North America relies heavily on bee-pollinated agricultural crops, including vegetables, fruits and clothing fibres such as cotton. Photo: Olga Koppel / University of Ottawa
North America relies heavily on bee-pollinated agricultural crops, including vegetables, fruits and clothing fibres such as cotton. Photo: Olga Koppel / University of Ottawa
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Bumblebees are waking up earlier from hibernation due to climate change, putting the species at risk with impact on human agricultural crops, a study has found. The early arrival of spring has been noted in many parts of North America. 

Bees are waking up before the arrival of spring flowers — their main food source, according to researchers from the University of Ottawa. The scientists have published a paper studying climate change’s influence on seasonal weather changes concerning bumblebees. 

The paper, Strong phenological shifts among bumblebee species in North America can help predict extinction risk, was published in the journal Biological Conservation. 

More than 180,000 plant species, including 1,200 crop varieties, across the world depend on pollinators to reproduce. 

Researchers found the bees are not correspondingly shifting their activity timing earlier in the year, threatening their ability to find food sources or causing bees to miss out on them altogether. This is leading to smaller bumblebee colonies with lower odds of persisting in that area the following year. 

Being able to match the timing of floral resources gives bumblebee species an edge. Bumblebees who sync with the changing timing of spring take full advantage of the season’s floral resources and are more likely to persist over time.

Conceptual representation of how climate change effects can be mitigated via a range shift. Photo: University of Ottawa

“This study represents crucial groundwork for understanding that climate can impact the seasonal timing of biological events,” says lead author Olga Koppel. “This study provides a roadmap for evaluating large-scale temporal responses to climate change for many insects and other animals.”

Koppel is a PhD student in the Faculty of Science’s Department of Biology at the university. The other lead author Jeremy Kerr is a full professor and chair in the Department of Biology. The two examined the relationship between climate and bumblebee spring emergence in a database of specimens.

The researchers looked at museum collections across North America, comprising 21 species and 17,000 individuals. Climate strongly explained variation in spring emergence timing in 15 of the 21 bumblebee species, they found. 

Bumblebee survival is strongly in our best interest, said Koppel. “North America relies heavily on bee-pollinated agricultural crops, including vegetables, fruits, and even clothing fibres such as cotton,” she said, adding the region has over 40 native bumblebee species. 

Climate change is being linked to global biodiversity decline and its impact on species is a quickly growing field of research. Climate change increases the likelihood of earlier spring onset and flowering in many areas, including spring plants, wild plants and trees.

These are a necessary food source for winter hibernating bumblebee queens, who search for pollen and nectar after waking up hungry in need of energy. 

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