Research: Rising temperatures threatening bumblebee populations

UPI
A bumblebee hovers over indigenous Fynbos vegetation in Cape Town, South Africa on March 24, 2006. A new report said that climate change is threatening the bumblebee population. File Photo by Nic Bothma/EPA

May 3 (UPI) -- New research from the University of Guelph said on Friday that temperatures are becoming too hot for bumblebees, threatening their role as plant pollinators and the food supply for humans and other animals.

Researchers said increasing heat is soaring past the optimal temperature for bumblebees, from 86 to 89.6 degrees. Guelph environmental professor Peter Kevan said while bees have the ability to thermoregulate the temperatures inside their hives, that can only work for so long.

The article appeared online Friday in the scientific journal Frontiers.

"The decline in populations and ranges of several species of bumblebees may be explained by issues of overheating of the nests and the brood," said Kevan, the article's author.

"The constraints on the survival of the bumblebee brood indicate the heat is likely a major factor, with heating of the nest above about 35 degrees Celsius being lethal, despite the remarkable capacity of bumblebees to thermoregulate."

Temperatures around the world have been rising for the past decades, rewriting the weather record book with each passing year. The year 2023 was the hottest ever recorded with temperatures poised to shatter that record this year.

"Excessively high temperatures are more harmful to most animals and plants than cool temperatures," Kevan said. "When conditions are cool, organisms that do not metabolically regulate their body temperatures simply slow down but when temperatures get too high, metabolic processes start to break down and cease. Death ensues quickly."

Kevan said pesticides, habitation loss, the shrinking availability of wildflowers, and disease also contribute to the population shrinkage. There are 250 different species of bumblebees, 49 of which can be found in the United States.