What Are They?
House flies are pests that like to feed on garbage and other food sources inside and outdoors, especially during warmer seasons. The house fly’s inclination to feed on a wide variety of matter and food items poses potential health risks to humans, as the pest often carries harmful, disease-causing pathogens from one food site to another.
What Do They Look Like?
Size: As adults, house flies typically range from 1/4 to 1/2 inches (6-13 mm) in length, with females being larger in size than males. House fly larvae, also known as maggots, are 1/4 to 3/8 inches (6-9.5 mm) long just prior to pupating.
Color: Adult house flies appear dull gray in color, while larvae are whitish or cream-colored with a greasy sheen.
Face: Fully grown house flies boast a pair of velvety stripes on their faces. The upper stripe appears silver in color and the lower one is gold.
Adults also feature a single pair of wings and four dark stripes that run lengthwise down the thorax, while the sides of the abdomen are usually pale and yellowish-white.
The mouthparts of the house fly work like a sponge and soak up liquids, as the insect cannot bite or chew. During the larval stage of the life cycle, house flies are eyeless, legless maggots with worm-like bodies that taper from the rear to the front.
What Do They Eat?
Restricted to a liquid diet, house flies nevertheless feed on everything from excrement to human foods. The diet of the house fly prominently includes moist decaying matter, such as garbage, rotten fruits and vegetables, and sewage. The pests can also consume solid foods by regurgitating saliva and liquefying the food source.
Do House Flies Bite?
No. House flies possess straw-like (sponging) mouthparts used solely for lapping, sponging, and sucking when taking in food. Consequently, the house fly remains physically incapable of biting humans or animals, and its primary defense mechanism is to fly away at the hint of danger. While some of the pest’s relatives, such as the stable fly, possess the ability to bite, house flies pose greater health risks by carrying disease-causing bacteria on their hairy legs and bodies.
House flies hatch from eggs that adult females deposit in moist decaying matter. The typical female house fly lays her eggs individually or in bunches of 20 to 50 and produces between 350 and 900 offspring over the course of her lifetime. Maggots hatch from the eggs in a mere 8 to 20 hours, feed on the decaying matter. Upon completion, house flies emerge as fully mature adults and typically live for 15 to 25 days. Read more about the house fly life cycle.
- Look for adult house flies around trash cans and other sites containing decaying matter.
- May notice fly specks, or fecal spots, on household surfaces.
- When resting on walls, house flies tend to remain within five feet of the ground during the day and climb to higher positions at night.
House Flies & Disease
Like other species of filth flies, the house fly breeds in and feeds on decaying matter, such as excrement, and regularly comes into contact with disease-causing microorganisms as a result. Problems arise when house flies transfer the pathogens to food items and household surfaces, thereby putting humans at risk of contracting a variety of potentially serious diseases. The pests defecate or regurgitate whenever they land on a surface and are capable of carrying over 100 different pathogens, including cholera, dysentery, typhoid fever, tuberculosis, and salmonella.
Signs of Infestation
Flying Around the Home
The mere presence of adult house flies often implies that an infestation is nearby, as the insects generally remain within a mile or two of their birthplace.
House flies also leave tiny fecal spots called fly specks on surfaces. In fact, determining the severity of a house fly infestation can be accomplished by strategically placing white spot cards around the home and counting the number of fly specks that appear after a week or so. Fifty or more fly specks generally signals the need to implement proper control measures, while anything over a hundred specks means that a serious infestations exists nearby.
The most effective ways to prevent a house fly infestation involve maintaining a sanitary home environment and barring the pests from entering in the first place. Effective sanitation entails removing spoiled food and garbage from the home, regularly cleaning and covering trash cans, and preventing organic matter, such as grass clippings, manure, and weed piles, from accumulating in the yard and decaying.
Similarly, excluding house flies from the home also requires the implementation of preemptive measures, such as checking and tightening window screens, keeping doors closed, and caulking or plugging any openings through which the pests could enter. Chemical methods, while available, typically fail to control house flies long-term, as the insects can become resistant to pesticides.
Tips for Removal from Home
Sticky traps, live-capture traps, and insect light traps may help alleviate a house fly infestation. Heat can also be used to eliminate house flies, as the pests will die in 30 minutes at a temperature of 120 degrees Fahrenheit. However, an integrated pest management plan (IPM) based on sanitation and exclusion represents the best approach to take when attempting to control and eradicate an infestation of house flies.