Flies and several other flying insects have the extraordinary ability not only to attack attached to inverted surfaces but literally to “land” on them and remain attached despite the impact of the landing itself and the same gravity. They seem to perform this movement of real aerial acrobatics without effort so much that this same feature has eluded scientists’ analyzes and studies for many decades. The interest in this particular feature, in fact, lies in the fact that these modalities could perhaps be imitated for new technologies.
It is precisely what a mechanical engineer from the Pennsylvania State University, Bo Cheng, is trying to do, who for several years has been trying to understand precisely this type of “landing” on the flipped surfaces of flies. He has begun to rummage through the scientific studies of the last fifty years but has found few things essentially for one reason: these “landings” are so fast that they are not very easy to observe.
The scientist, helped by some colleagues, has therefore used high-speed cameras to analyze various specimens of Calliphora vomitoria, also known as the blue flesh of the flesh. The researcher discovered that flies mainly refer to visual cues to perform this difficult maneuver. In the last moments before the contact with the ceiling, the fly makes a decision within 50 milliseconds: it turns its body upside down and sticks with the surface of its legs on the upside-down wall.
However, few landings failed, which demonstrates the difficulty of this maneuver. Time is of the essence as insects must perform the body roll-over maneuver in a small fraction of a second in order to achieve a perfect landing and avoid a direct collision with the ceiling. The movement sees an initial upward acceleration followed, a few tens of milliseconds before contact with the ceiling, by a very rapid rotation of the body and by an extension of the legs. This is followed by a final oscillation of the body that causes all the legs to remain in contact with the ceiling. These movements are strongly correlated to the stimuli that the same insect receives on the retina.
The study was published in Science Advances.