Bumblebee queens in hibernation can survive being submerged in water for days.

The life of a bumblebee queen isn’t always graceful or easy. In the spring, she can start building a nest, but first she must survive the winter alone, hibernating underground, exposed to floods and other hazards.

Luckily, this hardy queen is no slouch. Bumblebee queens can survive being submerged in water for up to one week.

Honeybee biologists Sabrina Rondeau and Nigel Lane came to this discovery after a lab accident at the University of Guelph in Canada. They were studying how hibernating queen bees react to exposure to pesticides when the refrigerator in which they kept the hibernating bees malfunctioned, flooding four vials containing the queens.

“I was very worried at first,” says Rondeau, now at the University of Ottawa, “and, of course, I thought she was dead.” But when he picked up the queen with tweezers, she started moving. She was definitely alive.

Rondeau and Laing decided to carry out more rigorous testing to see just how waterproof the queens were, and they published their findings in April. Biology Letters.

Weathering the storm

First, the researchers collected 143 queen bees from the common eastern bumblebee species (Bumblebee). All were left over from another experiment. The researchers placed each one in a vial filled with soil and kept it at low temperatures to mimic hibernation.

The vials were then filled with water so that the queens were either submerged or floating on the surface. Seventeen queens served as controls and had no water in their vials.

The submerged queens were then kept at cool hibernation temperatures for either 8 hours, 24 hours, or a week, after which they were transferred to vials of dry soil and kept at cool temperatures for a further 8 weeks.

The test setup mimicked possible real-world flood scenarios. It’s unclear how often rain would cause the queen’s hibernation chamber to fill or partially fill with water. In general, hibernating queens seem to prefer sloping or sandy ground, where flooding is less likely. Still, the new study suggests that queens can survive storms.

Of the 21 queens that were submerged for 7 days and then resumed hibernation, 17 were still alive after 8 weeks, a survival rate that was not statistically different from the 17 bees that were not submerged, 15 of which survived the full 8 weeks.

Rondeau said the submerged queen was soaking wet when she was first removed from the water, but by the next day, “she was fluffy and beautiful again, as if nothing had happened,” she recalled. “It was amazing.”

Royal Investigation

A queen’s ability to recover raises another question, says Lane: “Does it affect her ability to found colonies?” Or, more specifically, her ability to produce lots of healthy larvae and successfully establish colonies?

There’s also the question of how the queen bee survives submerged for so long. Many insects have adapted ways to avoid drowning, such as by closing their breathing slits, which queen bees breathe through spiracles. Rondeau thinks one factor may be that hibernating queens have a slower metabolism, which might allow them to keep their spiracles closed for longer than when they’re fully awake and active.

“What this study really tells us is how little we know about the life cycle of bumblebees, and how much we have to learn,” says Elizabeth Krohn, a biologist at the University of California, Davis, who was not involved in the study. “The interaction of flowers with bumblebees is one of the best-studied phenomena in ecology,” she notes. “In contrast, we know very little about nesting, hibernation, and reproduction.”

Source: www.snexplores.org