Bumblebee Queens Breathe Underwater to Survive Floods

Bumblebee queens possess a remarkable ability to survive prolonged submersion in water, a strategy crucial for enduring increasingly frequent flooding events. New research reveals these queens don’t simply hold their breath, but actively breathe underwater, utilizing a combination of underwater respiration, anaerobic metabolism, and a significant reduction in metabolic rate.

Underwater Respiration and Metabolic Slowdown

Researchers at the University of Ottawa in Canada discovered that hibernating bumblebee queens (Bombus impatiens) can survive for up to a week underwater. Initial observations stemmed from a lab accident where vials containing queens were flooded. Further experiments involved submerging queens in cold water for eight days to observe their physiological responses.

The queens’ metabolisms, already naturally suppressed during hibernation, slow down even further when submerged. This metabolic depression minimizes energy expenditure. Simultaneously, they switch to anaerobic metabolism, a process that doesn’t require oxygen, and, crucially, extract oxygen directly from the water.

How Do They Breathe Underwater?

While the exact mechanism of underwater respiration is still under investigation, scientists hypothesize that bumblebee queens may trap a thin layer of air around their bodies, similar to some aquatic insects. This allows them to access dissolved oxygen in the water. Measurements showed that submerged queens continuously released carbon dioxide, indicating ongoing respiration.

Recovery and Energy Reserves

Upon resurfacing, submerged queens exhibit an increased breathing rate for several days to clear lactic acid, a byproduct of anaerobic metabolism, from their systems. This recovery period highlights the energetic cost of underwater survival.

Researchers are now investigating how repeated or prolonged submersion impacts the queens’ overall energy reserves. With increasing frequency of heavy rainfall and flooding due to climate change, understanding the limits of this flooding-tolerance strategy is becoming increasingly important.

Implications for Bumblebee Conservation

This discovery reveals a remarkable adaptation in bumblebees, offering insights into their resilience against environmental challenges. Further research will focus on exploring the limits, mechanisms, and ecological significance of underwater survival in terrestrial insects.