Updated: May 30, 2023

Flies are one of the most common insects found all over the world. They are known for their distinctive buzzing sound and their presence around garbage cans and other sources of waste. Flies are often considered pests because they can spread diseases and cause irritation, but they also play an important role in the ecosystem as decomposers. In this article, we will explore what flies eat and their feeding habits.

Types of Flies

Before we delve into the diet of flies, it’s important to understand that there are many different types of flies. Some of the most common types include:

  • Houseflies: These are the most familiar type of fly and are found in homes, restaurants, and other indoor areas where food is present.

  • Fruit flies: These small flies are attracted to ripe or decaying fruits and vegetables.

  • Blowflies: These flies are attracted to dead animals and are often used by forensic scientists to estimate the time of death.

  • Horseflies: These large flies feed on the blood of mammals and can be a nuisance to livestock and humans.

  • Mosquitoes: Although not technically a fly, mosquitoes are a type of flying insect that feeds on the blood of animals, including humans.

What Do Flies Eat?

Flies have a wide-ranging diet that varies depending on the species. Generally speaking, most flies feed on organic matter such as decaying plant matter, animal carcasses, and feces. Houseflies are known to feed on a variety of food sources, including sugary substances like fruit juice, nectar, and honeydew. They also feed on rotting meat, garbage, and even fecal matter.

Fruit flies, as their name suggests, are attracted to ripe or rotting fruits and vegetables. They are particularly drawn to bananas, tomatoes, and other soft fruits. Blowflies also feed on dead animals, but they typically lay their eggs on the carcass, which then hatch into maggots that feed on the decaying flesh.

Horseflies and other biting flies feed on the blood of mammals, including livestock and humans. They use their sharp mouthparts to pierce the skin and suck blood, which can cause pain, irritation, and even disease transmission.

Mosquitoes, although not a type of fly, are also known for feeding on the blood of mammals. Only female mosquitoes feed on blood as they require the protein to produce eggs. Male mosquitoes feed on nectar and other sugary substances.

How Do Flies Feed?

Flies have a unique feeding mechanism that allows them to consume liquid or semi-liquid food sources. They do not have teeth, so they are unable to chew their food. Instead, they use their proboscis, a long, thin tube-like structure that extends from their mouth, to suck up liquids.

When flies land on food or other organic matter, they regurgitate digestive enzymes onto the surface. These enzymes break down the food into a liquid form that can be consumed by the fly. The fly then uses its proboscis to suck up the liquid food.

Why Are Flies Considered Pests?

While flies play an important role in the ecosystem as decomposers, they are also considered pests because they can spread diseases and cause irritation. Flies are known to carry a variety of pathogens that can cause illnesses such as diarrhea, cholera, and typhoid fever. They can pick up these pathogens from contaminated food or waste and then transfer them to human or animal hosts.

In addition to spreading disease, flies can also be a nuisance in homes and businesses. They are often attracted to garbage cans, compost piles, and other sources of waste. Once inside a building, they can contaminate food and surfaces with their feces and regurgitated digestive enzymes.

How to Control Flies

There are several ways to control flies and reduce their presence in your home or business. Here are a few tips:

  • Keep food covered and stored properly to prevent flies from accessing it.
  • Clean up spills and crumbs immediately to remove potential food sources.
  • Seal cracks and gaps in doors and windows to prevent flies from entering the building.
  • Use screens on windows and doors to keep flies out while allowing fresh air in.
  • Regularly clean garbage cans and compost piles to remove potential breeding grounds for flies.
  • Use fly traps or insecticides as a last resort if other methods are not effective.


Flies have a diverse diet that includes decaying plant and animal matter, sugary substances, and even blood. While they play an important role in the ecosystem as decomposers, they can also spread diseases and be a nuisance in homes and businesses. By understanding their feeding habits and taking steps to control their presence, we can reduce the negative impact of flies on our daily lives.