Queen bumblebees surprise scientists by surviving underwater
Linda GIVETASH
Tue, 16 April 2024
Researchers said more studies need to be done on whether other bumblebee species have a similiar trait (Damien MEYER)
Bumblebees can surprisingly withstand days underwater, according to a study published Wednesday, suggesting they could withstand increased floods brought on by climate change that threaten their winter hibernation burrows.
The survival of these pollinators that are crucial to ecosystems is "encouraging" amid worrying global trends of their declining populations, the study's lead author Sabrina Rondeau told AFP.
With global warming prompting more frequent and extreme floods in regions around the world, it poses "an unpredictable challenge for soil-dwelling species, particularly bees nesting or overwintering underground", co-author Nigel Raine of the University of Guelph said in a statement.
Rondeau said she first discovered queen bumblebees could withstand drowning by accident.
She had been studying the effect of pesticide residues in soil on queen bumblebees that burrow underground for the winter when water accidentally entered the tubes housing a few of the bees.
"I freaked out," said Rondeau, who had been conducting the experiment for her doctoral studies. "It was only a small proportion... so it was not that big of a deal, but I didn't want to lose those bees."
To her "shock", she said, they survived.
"I've been studying bumblebees for a very long time. I've talked about it to a lot of people and no one knew that this was a possibility," she said.
She launched another experiment to better understand what happened.
Researchers placed 143 hibernating queen bumblebees in tubes -- some with no water as a comparative group, some floating in water and some fully submerged using a plunger for a period ranging from eight hours to seven days, according to the study published in the journal Biology Letters.
Remarkably, 81 percent of the hibernating queens that were submerged not only survived seven days, but once returned to dry conditions remained alive eight weeks later.
The long-term impact on the bees' health and the effects it could have on a colony still needs further research, Rondeau noted.
The common eastern bumblebees used in the study are found in North America and are particularly hardy, not showing the same degree of population declines as other bee species, she said.
"So we are also wondering whether this resistance to flooding can be part of why they're doing so well," said Rondeau, now a postdoctoral fellow at the University of Ottawa.
The study would have to be replicated on other species of bumblebees to determine how common the trait is.
"But it's encouraging to know that at least (flooding) is not another big threat that we have to consider," she said.
giv/nmc/rlp
Linda GIVETASH
Tue, 16 April 2024
Researchers said more studies need to be done on whether other bumblebee species have a similiar trait (Damien MEYER)
Bumblebees can surprisingly withstand days underwater, according to a study published Wednesday, suggesting they could withstand increased floods brought on by climate change that threaten their winter hibernation burrows.
The survival of these pollinators that are crucial to ecosystems is "encouraging" amid worrying global trends of their declining populations, the study's lead author Sabrina Rondeau told AFP.
With global warming prompting more frequent and extreme floods in regions around the world, it poses "an unpredictable challenge for soil-dwelling species, particularly bees nesting or overwintering underground", co-author Nigel Raine of the University of Guelph said in a statement.
Rondeau said she first discovered queen bumblebees could withstand drowning by accident.
She had been studying the effect of pesticide residues in soil on queen bumblebees that burrow underground for the winter when water accidentally entered the tubes housing a few of the bees.
"I freaked out," said Rondeau, who had been conducting the experiment for her doctoral studies. "It was only a small proportion... so it was not that big of a deal, but I didn't want to lose those bees."
To her "shock", she said, they survived.
"I've been studying bumblebees for a very long time. I've talked about it to a lot of people and no one knew that this was a possibility," she said.
She launched another experiment to better understand what happened.
Researchers placed 143 hibernating queen bumblebees in tubes -- some with no water as a comparative group, some floating in water and some fully submerged using a plunger for a period ranging from eight hours to seven days, according to the study published in the journal Biology Letters.
Remarkably, 81 percent of the hibernating queens that were submerged not only survived seven days, but once returned to dry conditions remained alive eight weeks later.
The long-term impact on the bees' health and the effects it could have on a colony still needs further research, Rondeau noted.
The common eastern bumblebees used in the study are found in North America and are particularly hardy, not showing the same degree of population declines as other bee species, she said.
"So we are also wondering whether this resistance to flooding can be part of why they're doing so well," said Rondeau, now a postdoctoral fellow at the University of Ottawa.
The study would have to be replicated on other species of bumblebees to determine how common the trait is.
"But it's encouraging to know that at least (flooding) is not another big threat that we have to consider," she said.
giv/nmc/rlp
Nicola Davis
Science correspondent
The Guardian
Tue, 16 April 2024
A common eastern bumblebee in flight with pollen sacs.
Tue, 16 April 2024
A common eastern bumblebee in flight with pollen sacs.
Photograph: Nature Picture Library/Alamy
Bumblebees might be at home in town and country but now researchers have found at least one species that is even more adaptable: it can survive underwater.
Scientists have revealed queens of the common eastern bumblebee, a species widespread in eastern North America, can withstand submersion for up to a week when hibernating.
With bumblebee queens known to burrow into soil to hibernate, the researchers say the phenomenon could help them survive flooding in the wild.
The team said its next priority was to explore whether the results hold for other species of bumblebee.
“We know that about a third of all bumblebee species are in decline currently [but] it’s not the case with [the common eastern bumblebee],” said Dr Sabrina Rondeau of the University of Guelph in Canada, adding the team was keen to learn whether flood tolerance could play a role in their resilience.
Rondeau and her co-author, Prof Nigel Raine, first made their discovery when a mishap in the laboratory led to water getting into containers in which hibernating queen bees were kept.
“After that, of course, curiosity led the way to conducting a full experiment with a lot of repetitions,” said Rondeau.
Writing in the journal Biology Letters, the scientists describe how they took 143 unmated, hibernating queens of the common eastern bumblebee and placed each in its own plastic tube containing damp topsoil. The tubes were then fitted with perforated lids and kept in a dark refrigerated unit for a week.
After checking the bees were still alive, the researchers kept 17 tubes as controls and added cold water to the remaining 126. While the queen was allowed to float on top of the water in half of these tubes, it was pushed under the water by a plunger in the others.
For both conditions, a third of the tubes were each left for eight hours, a third for 24 hours and a third for seven days, simulating different flooding conditions. The team subsequently transferred the bees to new tubes and monitored their survival.
The results reveal survival rates were similar regardless of the duration and conditions the queens had been subjected to – indeed 88% of the controls, and 81% of the queens that were submerged for a week, were still alive at eight weeks. However, queens with a higher weight had a greater chance of survival.
The researchers say the findings are unusual given most insects overwintering as adults – including many ground beetles – cannot cope with being submerged in water and must leave floodplains to survive.
While Rondeau said it was likely queens of other bumblebee species were also flood tolerant, ground nesting bees – which include some species of bumblebee – could still be affected by flooding as their larvae may not survive.
Among future areas of research, the team said it would be interesting to explore the mechanisms that underpin the queens’ resilience to flooding – with their low oxygen requirements during hibernation among possible important factors.
Prof Dave Goulson, a bee expert from the University of Sussex who was not involved in the work, said bee enthusiasts had long speculated that increased winter rain amid the climate crisis could drown many queen bumblebees as they hibernate underground.
“Amazingly, this new research shows that hibernating queen bumblebees are entirely unaffected by being held under water for up to one week,” he said. “This seems to be one small aspect of climate change that we need not worry about.”
Bumblebees might be at home in town and country but now researchers have found at least one species that is even more adaptable: it can survive underwater.
Scientists have revealed queens of the common eastern bumblebee, a species widespread in eastern North America, can withstand submersion for up to a week when hibernating.
With bumblebee queens known to burrow into soil to hibernate, the researchers say the phenomenon could help them survive flooding in the wild.
The team said its next priority was to explore whether the results hold for other species of bumblebee.
“We know that about a third of all bumblebee species are in decline currently [but] it’s not the case with [the common eastern bumblebee],” said Dr Sabrina Rondeau of the University of Guelph in Canada, adding the team was keen to learn whether flood tolerance could play a role in their resilience.
Rondeau and her co-author, Prof Nigel Raine, first made their discovery when a mishap in the laboratory led to water getting into containers in which hibernating queen bees were kept.
“After that, of course, curiosity led the way to conducting a full experiment with a lot of repetitions,” said Rondeau.
Writing in the journal Biology Letters, the scientists describe how they took 143 unmated, hibernating queens of the common eastern bumblebee and placed each in its own plastic tube containing damp topsoil. The tubes were then fitted with perforated lids and kept in a dark refrigerated unit for a week.
After checking the bees were still alive, the researchers kept 17 tubes as controls and added cold water to the remaining 126. While the queen was allowed to float on top of the water in half of these tubes, it was pushed under the water by a plunger in the others.
For both conditions, a third of the tubes were each left for eight hours, a third for 24 hours and a third for seven days, simulating different flooding conditions. The team subsequently transferred the bees to new tubes and monitored their survival.
The results reveal survival rates were similar regardless of the duration and conditions the queens had been subjected to – indeed 88% of the controls, and 81% of the queens that were submerged for a week, were still alive at eight weeks. However, queens with a higher weight had a greater chance of survival.
The researchers say the findings are unusual given most insects overwintering as adults – including many ground beetles – cannot cope with being submerged in water and must leave floodplains to survive.
While Rondeau said it was likely queens of other bumblebee species were also flood tolerant, ground nesting bees – which include some species of bumblebee – could still be affected by flooding as their larvae may not survive.
Among future areas of research, the team said it would be interesting to explore the mechanisms that underpin the queens’ resilience to flooding – with their low oxygen requirements during hibernation among possible important factors.
Prof Dave Goulson, a bee expert from the University of Sussex who was not involved in the work, said bee enthusiasts had long speculated that increased winter rain amid the climate crisis could drown many queen bumblebees as they hibernate underground.
“Amazingly, this new research shows that hibernating queen bumblebees are entirely unaffected by being held under water for up to one week,” he said. “This seems to be one small aspect of climate change that we need not worry about.”
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