Bumblebees carry lots of cargo in economic mode, Bumblebees (Bees) are the biggest insect killer in the world that can fly back to the nest with the same weight.
A study published on February 5 in Science Advances shows how they do it and bees can act more flexibly than you would expect from buzzing insects.
They can carry 60, 70, or 80 percent of their body weight to fly, which will be a huge burden for us to leave, the researchers said. Bumblebees carry lots of cargo in economic mode.
We love seeing how they do it and how much it costs them to bring food and supplies back to the honeycomb.
Gagliardi and Stacy Combes, assistant professors in the Department of Neurobiology, Physiology and Behavior, measured the energy consumption of bees that flew in specially designed rooms (empty snow branches).
They attach small pieces of solder wire to the bees to adjust their weight.
We put bees in a small chamber and measure the carbon dioxide they produce. “They mainly burn sugar so you can immediately see how much sugar they consume during the flight,” Galiardi said.
They also use high-speed video to check the effects and movements of the wings.
Flying bees are very different from planes, Combes said. When air flows evenly over the plane’s wings or rotor blades, the bee moves its wings at a large angle to the air and creates curved vortices around the wing. This produces more buoyancy than stable air flow, but it is not stable because the vortex breaks out quickly. Bees can fly by moving their wings very quickly.
When bees remove fuel from the nectar they carry, they must become lighter when they fly and use less energy. To their surprise, Combes and Gagliardi found that bees could actually use less energy per unit charge if they were loaded more. Bumblebees carry lots of cargo in economic mode.
“You will be more economical to fly the heavier ones that are lost, which makes no sense from an energetic perspective,” Combes said.
On closer examination, the researchers found that bees could overcome the increased load in two different ways. They always increase the amplitude of the collision (how wide the wings are) when they are loaded, but this is not enough to carry extra weight alone.
To compensate for the difference, bees can increase the frequency of wing beats, create more buoyancy and increase energy costs.
However, bees also have alternative, very different flight modes, which allow them to carry heavier weights by using less energy than when increasing vibrational frequencies.
It is not yet clear what exactly involves this “economic mode”, Combs said, although it might involve changes in the way the wings rotate in the opposite direction between beats. But bees can choose to do something or not.
“It turns out they chose to maintain workload behavior,” Combes said. When bees are loaded or lightly rested, they tend to increase the frequency of the wings.
When under heavy loads, they switch to mysterious economic modes that produce enough power to support the load with only a slight increase or even decrease in the frequency of the sweep.
If bees can save energy while flying, why not always use this economic mode? It’s unclear, but high-frequency wing beatings may have performance advantages such as maintaining stability in storm air or avoiding obstacles, Combes said.
The work has changed the way Combes see insects, he said.
When I started in this area, I saw it more as a small engine. “We decided that once they swing their wings when they don’t carry a burden, on the contrary when they carry a 50 percent load and every bee does the same thing every time,” he told researchers.
This gives us an estimate that this is behavior, they choose what to do. Even the same bee on another day will choose a new way to flap its wings.