Facts about the animal kingdom

How Are Flies Born in the House?

Cristina Pérez Simón
By Cristina Pérez Simón, Biologist and Agroecology student. March 15, 2024
How Are Flies Born in the House?

While houseflies are a constant buzzing annoyance, their presence goes beyond disrupting your breakfast. Left unchecked, these pests can multiply rapidly and pose significant health risks. Houseflies act as carriers for various diseases and pathogens, including bacteria like E. coli and Salmonella, as well as viruses and parasites.

This article by AnimalWised will delve into houseflies reproduction, examining their life cycle, breeding behaviors, and effective methods for elimination and prevention.

You may also be interested in: Are Blue Bottle Flies Dangerous?


  1. How do flies reproduce in the house?
  2. Where do flies lay their eggs in the house?
  3. What will keep house flies away?
  4. How do I get rid of a fly infestation in my house?

How do flies reproduce in the house?

Flies reproduce in the house through a process known as oviposition, which involves the deposition of eggs by adult females in suitable breeding sites within indoor environments. The life cycle of flies comprises four distinct stages: egg, larva (maggot), pupa, and adult. Here's a breakdown of their lifecycle:

Egg deposition

Female houseflies are opportunistic breeders, constantly searching for suitable locations to lay their eggs. They're particularly drawn to decaying organic matter like food scraps, rotting fruits, and even pet waste. These materials provide essential nutrients for their developing offspring. Warm and moist environments like compost piles or improperly sealed garbage bins are also prime targets.

Once a suitable location is identified, the female fly lays a cluster of tiny white eggs, typically numbering around 100-150 at a time. These eggs hatch rapidly, often within a day or two under warm conditions.

Larval development

The hatched eggs transform into maggots, the larval stage of the fly. These legless, worm-like creatures spend their days feeding on the surrounding organic matter. As they grow, they go through several molting stages before reaching their full size. Also, the larvae undergo several molts as they grow, with their feeding activity contributing to the decomposition of organic matter.

Pupation and transformation

After reaching maturity, the maggots find a secluded spot to pupate. They form a brown, hardened puparium (protective case) around themselves. Inside the puparium, a dramatic transformation takes place. Over a period of several days, the maggot develops into an adult fly. Pupal development occurs in secluded areas within the house, such as cracks, crevices, or concealed spaces, where pupae are sheltered from disturbance.

Emerging adults

Finally, the adult fly emerges from the puparium, ready to find food, mate, and repeat the breeding cycle. This entire process, from egg to adult, can take as little as a week under ideal conditions, which is why house fly infestations can grow out of control quickly.

Curious about the specific threats posed by blue bottle flies? Dive deeper in our follow-up article.

Where do flies lay their eggs in the house?

Houseflies are opportunistic insects that readily exploit suitable indoor environments for egg-laying. Their success hinges on identifying locations that provide optimal conditions for larval development.

They are particularly attracted to decomposing organic materials. Food scraps, rotting produce, and other organic debris offer a rich nutrient source that fuels larval growth. Kitchens, garbage disposal areas, and any location where organic matter accumulates are prime targets for egg deposition.

Also, areas contaminated with pet feces are highly attractive to houseflies. The protein-rich nature of animal waste serves as a readily available food source for developing larvae. Maintaining proper pet waste hygiene by promptly removing and disposing of feces is crucial for preventing housefly infestations.

In general, accumulated garbage, both indoors and outdoors, serves as a prime breeding ground for houseflies. Open trash cans, improperly sealed bins, and food waste disposal areas offer ideal conditions for egg deposition and larval development. Furthermore, composting can also unintentionally attract houseflies. The warm, moist environment created during the decomposition process provides optimal conditions for egg-laying and larval development.

Ever wonder if those pesky flies buzzing around can actually bite? Dive deeper into the world of fly anatomy and discover their surprising biting capabilities in our related article.

How Are Flies Born in the House? - Where do flies lay their eggs in the house?

What will keep house flies away?

The best defense against a fly infestation is to prevent them from reproducing in your home in the first place. Houseflies thrive in environments that cater to their basic needs for reproduction and development. Let's explore the key factors that influence indoor fly populations and how to keep them at bay.

Sanitation and cleanliness play a crucial role in minimizing housefly breeding opportunities. As mentioned earlier, flies are drawn to decaying organic matter, which serves as a food source for their developing larvae. By maintaining a clean environment, you eliminate these attractive breeding grounds. This includes:

  • Store food in airtight containers to prevent rotting and attracting flies.

  • Regularly empty trash cans and dispose of food scraps to eliminate potential breeding sites.

  • Don't allow spills or sugary residues to linger on surfaces. Clean them promptly to remove potential food sources for flies.

  • Dispose of pet feces promptly and hygienically. Remember, animal waste is a rich source of nutrients for fly larvae.

But that is not all, the combination of temperature and humidity can also significantly impacts fly population growth indoors. Houseflies thrive in warm environments, with optimal temperatures ranging from 75°F to 90°F (24°C to 32°C). In this sense, kitchens, utility rooms, and sunlit areas provide these ideal conditions, accelerating larval development and overall fly reproduction.

While not as crucial as temperature, moderate humidity levels can also contribute to faster development for fly larvae.

Furthermore, there are several common household practices can inadvertently promote fly reproduction:

  • Leaving out overripe fruits on the counter or in bowls creates a feast for flies, attracting them to lay eggs.

  • While composting offers environmental benefits, neglecting proper techniques can backfire. Improper aeration and moisture levels in compost piles can create a breeding ground for flies.

  • Leaving windows and doors open for extended periods without screens can provide easy access for flies to enter your home. You can also install screens on windows and doors to prevent flies from entering your home, or use door sweeps and weather stripping to seal gaps around doors and windows.

Additionally, although not a comprehensive solution, certain natural repellents can assist in deterring flies. Consider strategically placing basil plants or utilizing essential oils such as citronella, lemongrass, or lavender. These oils can be diffused in an oil diffuser to help repel flies effectively.

How do I get rid of a fly infestation in my house?

If you're currently dealing with a fly infestation in your home, there's no need to panic. There are steps you can take to eliminate the problem and prevent future occurrences. One effective approach is to set up various traps designed to catch adult flies. These traps can include:

  • Sticky traps: place these near breeding sites or areas with high fly activity.

  • Fly swatters: while old-fashioned, they can be effective for eliminating small numbers of flies.

  • Targeted sprays: use insecticides specifically designed for houseflies. Always follow the instructions carefully and prioritize treating areas where flies congregate.

You can also create your own homemade traps. Create a vinegar and dish soap trap. Mix equal parts apple cider vinegar and dish soap in a shallow bowl or jar. Cover with plastic wrap, secure it with a rubber band, and poke small holes on top. Flies are attracted to the vinegar but get stuck in the soapy water.

If the infestation persists despite your efforts, consider hiring a pest control professional with experience in fly control. Pest control professionals can assess the extent of the infestation, identify contributing factors, and implement targeted treatments to eliminate flies from your home effectively.

Ever wondered why flies seem to be constantly cleaning their legs? We delve into the fascinating reasons behind this behavior in another article.

If you want to read similar articles to How Are Flies Born in the House?, we recommend you visit our Facts about the animal kingdom category.

  1. Khamesipour, F., Lankarani, K.B., Honarvar, B., & Kwenti, T.E. (2018). A systematic review of human pathogens carried by the housefly (Musca domestica L.) . BMC Public Health, 18(1), 1049.
  2. McIntyre, G.S., & Gooding, R.H. (2000). E gg size, contents, and quality: maternal-age and-size effects on house fly eggs . Canadian Journal of Zoology, 78(9), 1544-1551.
  3. Carrillo, J., Danielson-François, A., Siemann, E., & Meffert, L. (2012). Male-biased sex ratio increases female egg laying and fitness in the housefly, Musca domestica . Journal of ethology, 30(2), 247-254.
  • Hickman, C.P. et al. (2009). Comprehensive principles of Zoology . McGraw-Hill, Madrid.

Write a comment
Add an image
Click to attach a photo related to your comment
What did you think of this article?
1 of 2
How Are Flies Born in the House?