What are blowflies? How are they different from house flies?

Quick Answer:

The size of blow flies is similar to house flies, however, they are metallic blue or green instead. Adults buzz loudly and continuously. They thrive on garbage, animal waste, and excrement. Their flight range is 3 to 10 miles, and they fly more powerfully than house flies.

Blow flies, also known as bottle flies are tiny scavenging pests that usually come in groups called swarms or clouds. They can be metallic green, blue, black, or bronze in color; their very metallic appearance is often what helps to identify this species of fly. 

These are small flies with short legs and a large head that are attracted to the stench of rotting flesh. They feed on carrion, which is dead animal matter.

Adult blow flies live outdoors near surfaces that allow them access to moisture, such as damp soil, ditches, flower pots, tree bark, woodchips, yard debris, and even on garbage dumps.

They can also be commonly found indoors around leaky pipes or damp foundation walls but not necessarily inside your house because they don’t like the smell of human beings.

Blowflies can be a real nuisance for humans because they can enter homes and other buildings through open windows or doors. They breed in moist areas, so keeping your home dry is one of the best ways to prevent them from entering.

How Are Blowflies Different from House Flies?

Blow flies have short legs and a large head as compared to house flies, which have longer legs and smaller heads. With an average size of 8–10 mm (0.3–0.4 inch), they are slightly larger than houseflies but resemble them in habits. 

The lack of feet on the female blow fly means that they do not land on surfaces like ditches or flower pots but instead use their wings to hover over wet surfaces before landing.

Blow fly larvae & adult blow flies

Blow fly eggs are laid anywhere damp; these include puddles of water around trees, under bird baths, besides pet dishes (or kitty litter), on insulation materials such as unfinished basement walls or attics, or even in wet clothing left out overnight.

Some species of blow flies lay eggs on a dead animal and even in the wounds or sores of a live animal.

Their larvae, also known as maggots, measure 9 to 22 mm in length. They are also soft and appear similar to tiny worms or grains of rice. 

From eggs, maggots hatch within a few hours to a few days depending on the species. These maggots undergo three stages within several days, after which they leave their food source and pupate in the soil. Within a few days, the pupation will be complete, at which point they emerge as adults.

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Uses of Blow flies

The blow flies are of particular interest to scientists in that they can be used as indicators of the presence of carrion, which is a term for the dead animal matter. This is important because when the blow flies are present, it indicates that there is a decomposing animal nearby.

Carrion can attract predators and other scavengers, so the presence of these insects may help prevent the occurrence of diseases like anthrax or rabies in humans or animals.

People who hunt animals and target specific gamebirds also use blowflies to signal the presence of their kill and attract other hungry predators.

Many people believe that blowflies are a sign of death nearby but this isn’t true. Blowflies are actually more closely associated with decomposition, which is why they tend to live in areas where there is plenty of rotting garbage, such as dumpsters and compost piles, as well as around dead animals like deer or cows.

How do you attract blowflies?

Blowflies are attracted to the putrefying odor of dead animals and open wounds or skin infections. If your pet is harboring an open wound, he or she is vulnerable to having a wandering female blow fly lay eggs on them.

The best way to attract swarms or clouds of blowflies is with rotting meat. The meat of dead animals is essential for larval survival and growth.

If you want to attract them indoors, try leaving wet clothing outside overnight or around a bird bath that releases water into the air.

If you see an infestation of these little pests in your yard or house—or if you want to identify one that wandered into your home—you can also put out some dried milk in jars or other containers for them to land on. They will crawl inside and die there.

Another most common way is to use a small tent with a piece of cheese on the inside. The fly will be attracted to the smell and enter the small space, where it can’t escape. If you have a blowfly trap, you can use that to trap the flies.

How to identify male and female blowflies

Many people are not aware of the differences in sex flies, the male and female. Male and female blow flies are easy to tell apart.

Male blow flies have three dark bands on the abdomen, while females don’t. The male fly also has a more slender head, a dark thorax (middle body), and is about 1/3 shorter than the female.

Female blowflies lay eggs that only hatch into larvae in moist environments with a temperature of between 65 and 80 degrees Fahrenheit. In other words, they need a humid environment to complete their life cycle.

What are some ways to prevent blowflies from entering your home?

 A blow fly infestation often indicates a more serious issue. These pests gather in large numbers around the carrion. An indoor swarm is a sign of an animal carcass trapped in an attic or wall void.

One way to keep them from entering your house is by making sure your home has no sources of moisture that could offer food for the insects and is dry inside, typically through the use of air conditioning units and dehumidifiers.

In order to prevent blowflies from entering your house, you need to keep all entry points closed and make sure that there is no moisture or food available inside your home.


Blowflies are small flies with short legs and large heads that feed on the stench of rotting flesh. They have been associated with disease transmission to humans and animals that’s why it is important to get rid of blow flies.

Blow flies can enter homes through open windows or doors. If you are seeing blow fly indoors, chances are there is something rotting nearby. Once you have discovered Blow Fly activity, it is time to begin treatment. 

The most effective way to get rid of blow flies from your property is to contact a professional pest control expert at the first sign of their presence 


How do blowflies enter homes?

Blow flies are dangerous. Since they are attracted to the smell of rotting flesh, they are also an excellent indicator of the presence of disease in an affected area. Once they detect a potential food source, they will follow the scent around until they find an opening.

There is a hole in the roof above your home that allows them to enter, called an entry point. If you want to prevent blowflies from entering your house, make sure that there aren’t any openings for them to use as an entry point. This would include any holes in the roof or broken windows.

Place cork boards on top of holes in your roof and cover any cracks in windows or doors with caulk or plastic wrap. You should also clean up any animal carcasses in wet weather or when you are not home

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