We’ve all been there — enjoying a meal when a fly decides to make a touchdown on your food, and starts rubbing its leg together in anticipation of a feast. While you may just shoo it away and continue eating, this video may give you second thoughts the next time it happens.
Flies lack jaws or teeth. instead they have a specialized mouthpart called a “labellum” that works like a sponge to soak up liquid and semi-liquid foods. The first thing it does when it lands food is vomit a drop of digestive fluid to dissolve the food before slurping it up.
This unique feeding process allows flies to extract nutrients without the need for chewing. But it also means they spread their germs onto whatever they land on. Flies, which aren’t picky eaters, can transmit dangerous microbes like E. coli and Salmonella, turning your salad into a bacterial breeding ground.
And what about the leg rubbing? The narrator explains, “This behavior is essentially how a fly cleans or grooms its front legs. Flies use their legs to explore their environment, gather information about their surroundings, and locate sources of food. A fly’s legs also play a role in their feeding process. Grooming helps clean their legs after feeding and prevents any residual digestive fluids from interfering with their ability to fly or send to their environment.”
