As a result of the climate crisis, global warming is driving up temperatures around the world—and bumblebees, like humans, are struggling to cope with homes that can’t beat the heat.
In a new article published in Frontiers in Bee Science, scientists identify rising heat as a potential culprit for the decline in bumblebee populations worldwide, compromising bumblebees‘ ability to construct livable nests in which healthy larvae can develop.
“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 Dr. Peter Kevan of the University of Guelph, Canada, lead author of the article.
“The constraints on the survival of the bumblebee brood indicate that 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.”
There are many bumblebee species around the world, living in many different environments. Lots of these species are in a decline linked to climate change, but identifying a causative factor has proven difficult.
However, by reviewing the literature, Kevan and colleagues identified a critical commonality between these species, regardless of geographic range: the optimal temperature of their nests, 28–32 degrees Celsius.
“We can assume that the similarity reflects the evolutionary relatedness of the various species,” said Kevan.
Because this characteristic appears to be common between so many species, it may have limited evolutionary plasticity, meaning the bumblebees would find it hard to adapt to rising temperatures, and would struggle to remain within their thermal neutral zone—a point at which staying the right temperature requires minimal metabolic expenditure. Heat stress that takes a species out of this range is dangerous.
“Excessively high temperatures are more harmful to most animals and plants than cool temperatures. 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,” said Kevan. “Death ensues quickly.”
Reviewing 180 years of literature, Kevan and colleagues found that bumblebees seem to be able to survive at up to 36 degrees Celsius and develop optimally at around 30–32 degrees Celsius—though this might differ between species and biogeographical conditions. While bumblebees have some behavioral adaptations that allow them to thermoregulate, this may not be enough to deal with climate change.
Additionally, the bumblebee colony also acts as a “superorganism,” where reproductive fitness is dependent on the collective survival and reproduction of the colony rather than individual bees.
One bumblebee may cope better with the heat than another, but if the nest is too hot to raise healthy larvae the whole colony suffers, regardless of individual bumblebees’ adaptation.
On a wing and a prayer
“The effect of high nest temperatures has not been studied very much, which is surprising,” said Kevan. “We can surmise that nest temperatures above the mid-30s Celsius would likely be highly detrimental and that above about 35 Celsius death would occur, probably quite quickly.”
Studies of honeybees show that higher nest temperatures compromise bee queens’ strength and reproductive ability, and lead to smaller worker bees in poorer condition. If heat has a similar effect on bumblebees, so that colonies produce less healthy offspring at a higher temperature, then global warming could be directly leading to their decline.
To ensure that bumblebees continue to thrive, the scientists call for more research into what they say is an understudied aspect of bumblebee ecology: nest morphology, material properties, temperature, and thermoregulation. It may be possible for some bumblebee colonies to adapt their nest site choice and form or behavior to cool their nests.
Ground-penetrating radar could help study ground-nesting species, while flow-through respirometry analysis of nests at different temperatures might help scientists gauge the stress placed on the bee colonies inside. We need both to understand how different colonies cope with the same conditions and how different species cope with different conditions, including whether some bumblebee species have broader thermal neutral zones, affording them more resilience.
“We hope that future scientists may take the ideas we present and apply them to their own research on bumblebee health and conversation,” concluded Kevan.
More information:
Thermodynamics, thermal performance and climate change: Temperature regimes for bumblebee (Bombus spp.) colonies as examples of superorganisms, Frontiers in Bee Science (2024). DOI: 10.3389/frbee.2024.1351616
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
