When we think of flies, we have an image of invertebrates constantly moving their front legs. This is no surprise; you’ve probably seen flies rub their legs together after landing on something. But why do they do it?
There is an explanation for all behavior in the animal world, even if it seems arbitrary. This explanation comes from centuries of survival. Here are some of the biological reasons why flies rub their legs together. Don’t miss it!
What Exactly Is a Fly?
All flies are insects that belong to the order Diptera. They are one of the most diverse organisms, containing about one million species. Flies are closely related to blood-sucking insects such as mosquitoes, horseflies, and hoverflies. All of these invertebrates are characterized by their excellent ability to fly.
Most of the domestic species of flies are houseflies. These Diptera can be found almost anywhere globally, especially in areas of high human activity. It is associated with urban areas because it uses feces and garbage as food.
Although they fly over artificial environments almost all year round, they live longer and are more active in seasons when temperatures are between 10 and 26 degrees Celsius. For this reason, they are most commonly associated with spring and summer. The lifespan of an adult fly is 15 to 25 days, and an adult female can lay up to 150 eggs before dying.
Why Do Flies Rub Their Legs?
Now that we understand a little more about flies’ biology and behavior, let’s answer the question. There are two main reasons, which we will look at in detail in the next lines.
Believe it or not, flies have many chemoreceptors (a specialized sensory receptor cell that transduces a chemical substance) distributed throughout their body, and they recognize stimuli by their sense of touch. The third segment of the antennae and the maxillary palate represent the sense of smell. In contrast, the sense of taste is located in the rod, pharynx, limbs, wingtips, and female genitalia.
Thus, a fly can determine whether an object is edible or not simply by landing on its surface and walking over it. These dippers rub their feet together (presumably) to stimulate their chemoreceptors to recognize better the substance they are about to put in their mouth.
This point is closely related to the previous one. Since the forelimbs contain taste receptors, they need to be kept as clean as possible to register them effectively and quickly. Unfortunately, flies carry a lot of dirt (dust, pollen, liquids, etc.) when they land on a surface and fly away.
Therefore, when Diptera land on a surface, they first rub their legs together to clean themselves. Not only that, but they also try to clean their heads, wings, abdomen, and other limbs. Although they have an image of being dirty, they are actually very clean.
Flies: A World Full of Secrets
Discovering the truth about why flies rub their legs together is a real surprise. However, there are many other exciting facts about Diptera. For instance, they fly at a speed of 10 kilometers per hour and perceive time in “slow motion”. They also have a 360 degree field of view.
Unfortunately, the coexistence of humans with these dipterans is contradictory. Flies harbor bacteria and other parasites in their legs, transmitting diseases if they land on our food, so we have to keep them out of our homes. They are fascinating creatures, but the best thing to do is to keep them away. To do this, you need to keep the house clean and uncluttered.