Bumblebees turn from stealthy fighter jets to big jumbo jets when they’re carrying a full load of pollen instead of nectar, according to the first study of its kind to look into bee flight dynamics.

The findings were published in the Proceedings of the National Academy of Sciences, and it shows that there is a very big difference between how bumblebees fly depending on what their cargo is: nectar or pollen, according to Discovery News report.

Based on research, scientists now know that bumblebees can carry about half their body mass in pollen, and close to their body mass in nectar. That’s because of differences in how it is stored: nectar is stored within the abdomen, whereas pollen must be carried on its legs. Because of this difference in load position, the insect flies differently.

But why is this the case? Scientists believe that when bumblebees are carrying pollen, they have more stability, because the two different sides of the body would be balanced out thanks to two sets of legs. However, while it would mean more stability, it would also mean less agility, making it more difficult for the insect to turn.

However, when carrying nectar, researchers believe that it actual adds maneuverability because the weight is nearer to the center of gravity than the pollen is.

So scientists set out to test these concepts, using a wind tunnel and a robotic flower, and then they took notes on how 14 bees performed under different conditions. They used high-speed video to take data and measurements.

They found that bees that landed on stationary flowers in turbulent wind had better stability when loaded with pollen, although it couldn’t maneuver as well when it was loaded with nectar.