One of the distinctive features of flies is that they like to rub their legs. At the risk of being killed, they sit in the most prominent place and begin to perform hygiene procedures. Why do they do this?
Leg structure
To start with, we look into the structure of fly legs. All of their six legs end in pulvillae consisting of fine bristles, or microfibers. Each of the bristles has a disc-shaped suction cup that releases a liquid made of carbohydrates and fat. This liquid is the very secret that helps flies to deceive the laws of gravity.
The sticky liquid makes it possible to move not only over complex objects (for example, glass, ceiling or wall), but also over a horizontal surface. Without it, a fly can only slide.
What rubbing legs has to do with it?
This “glue” has its drawbacks — it collects dust and quickly loses its properties. Microparticles from the environment are collected on the bristles. They cover the discs and prevent liquid from flowing out of the bristles. As a result of this, the quality of movement deteriorates. In order not to lose the ability to move, flies have to perform hygienic procedures of rubbing their legs.
Interestingly, these bristles are also the organs of touch and taste in flies. That is, they can clean their legs for two reasons: to have an ability to move and taste.
According to scientific studies, flies can taste with their legs much better than humans. With their receptors, which are located on the bristles, they are able to rapidly determine the level of edibility of an object.
So, the answer is correct: flies clean their legs this way. Although they are carriers of many diseases, they still like to be clean.
This can’t be reproduced
This unusual ability of insects was noticed when creating a suit with velcro fasteners for movement over vertical surface. But that suit was very heavy and was not brought into mass production.
Only flies?
Apart from flies, geckos have this unusual ability. These lizards, because of a large number of microscopic hairs on their legs, are able to move over trees, walls and other vertical surfaces.
