PNAS= Post Nature and Science.[Figure 1. When bees collect water, they occasionally fall into the water. At this time, we must find a way to go ashore. Bees use their wings as paddles, paddle water to the shore, then wait for the wings to dry, and fly home! So how does a bee swim? A recent article was published]
Bees occasionally fall into the water, and then, the wings still vibrate, but the frequency is much lower, but the bees will swim forward. I think everyone has seen this phenomenon, and I have seen it several times. But didn’t care. I think it’s almost like fanning the wings in the air. However, when two physicists at the California Institute of Technology discovered this, and thought it was fun, they caught more than 30 bees and went to the laboratory for experiments. An artificial model was also created to simulate the swimming of bees so that some parameters could be calculated. The final paper was published in the Proceedings of the National Academy of Sciences (PNAS). This is behind Nature and Science, so some people joked that PNAS = Post Nature and Science.
Experimental method: The bee is placed in a small tube, and then the bee is gently dropped off the water. The water temperature is above 20 degrees (not mentioned a few degrees. It is estimated that the room temperature is about 25), and the water depth is 2.5-5 cm. High-speed photography (500-1000 pairs per second, oh, I don’t have this. Generally, the camera is about 120 at most). The measured vibration frequency of the wings is 71.6 Hz (number of times per second), which is significantly lower than 200-250 Hz in flight and 170 Hz in fan wind. The swimming speed is 1.4-4.3 cm / second. That is, you can swim as long as 1 to 4 bodies per second (faster than ordinary people?). When a bee swims, its wings are dry and its bottom is wet, and the wings have a figure-eight rotation (eversion and eversion) just like when flying, to generate thrust (like your hand, during breaststroke, go When turning upwards, try to keep the resistance as low as possible, and when turning down, try to make the resistance as large as possible, so that the thrust is generated, so the angle of the hand is always changing, and the same is true when the wings are flying). The power generated on the water surface is actually very small, about 20 micronewtons. The lift generated by bees flying is about 1,000 micronewtons. Is it a direct thrust, or a water wave from the wings, that eventually pushes the bee? I don’t understand very well (so, I’m not in physics, I can’t write such an article). Looking at the article is like the former, but many online interpretations consider it to be the latter, and later videos also say the latter.
The article then discusses the results of the mechanical model. It mainly depends on the direction and strength of water flow. Finally, the swimming methods of other insects are discussed. Said that the method of bees is unique, because if other insects do not swim underwater (such as beetle and paddlefish), that one should not be much different from normal swimming? The article states that these insects rely on steady-state inertial forces, while bees rely on non-steady-state inertial forces (I don’t know much about this!). If it ’s not on the water (such as a cricket called Jesus worm), it ’s a lot of oil on your feet, so that your feet do n’t damage the surface tension of the water Shen, is a principle), provided that the body is very light. Another fun method is to release thrust by releasing some soap-like chemicals to destroy the surface tension of water in one direction.
Watch a movie.
