How Long Does It Take for Fly Pupae to Hatch? Quick Facts and Insights

Fly pupae development time plays a crucial role in determining the overall life cycle of a fly. The time it takes for fly pupae to hatch relies heavily on the specific species of the fly and the environmental conditions they are exposed to.

House flies, for example, complete their pupal development in a relatively short time frame. At temperatures between 32 to 37°C, pupae develop in just two to six days. Comparatively, when exposed to cooler temperatures, around 14°C, the process takes significantly longer, requiring 17 to 27 days for completion.

On the other hand, horn fly larvae tend to develop through three instars within four to eight days before reaching maturity, highlighting the variations in development times across different fly species. Environmental factors, such as temperature and humidity, can also greatly impact the hatching time for pupae.

Life Cycle of a Fly

Eggs

Fly eggs are small, oval-shaped, and usually white in color. Female flies, especially the house fly, lay their eggs in moist environments like decaying matter or pet waste. The number of eggs depends on the fly species, but a female house fly can lay up to 500 eggs in her lifetime. The eggs hatch into larvae within 12-24 hours of being laid.

Larvae (Maggots)

The hatched larvae, commonly known as maggots, are legless worm-like creatures that feed on the surrounding organic matter. They go through three molting stages, called instars, increasing in size each time. This phase lasts about five days.

Pupae

After the final molt, the maggot enters the pupal stage. During this stage, the maggot’s body undergoes significant transformation, developing an exoskeleton and wings. Pupae do not feed and remain inactive. The duration of this stage depends on the species and environmental conditions but generally lasts around 3-7 days for common flies like the house fly and yellow fly.

Adult Flies

After the pupal stage, a fully formed adult fly emerges. Adult flies have wings and are capable of breeding. The average life span of an adult fly ranges from 15-30 days, depending on the species and environmental factors.

Key Characteristics:

• Eggs: small, oval, and white
• Larvae (maggots): legless worm-like creatures
• Pupae: inactive, transformation
• Adult flies: wings, capable of breeding

Comparison Table:

The life cycle of flies, from egg to adult, varies by species and environmental conditions, but generally completes within a month. Understanding this lifecycle can help in controlling and reducing fly populations, especially in areas where flies can become a pest or transmit diseases.

Hatching Process

Influential Factors

• Temperature: The hatching process is highly influenced by the temperature of the surrounding environment. For example, higher temperatures typically promote faster development and hatching of the pupae, while cooler temperatures can result in prolonged development times.
• Humidity: Humidity levels play a critical role in the hatching of fly pupae. The higher the humidity, the greater the chances for successful hatching.
• Feeding: The availability of food sources for the larvae stage can impact the hatching process.

Timeline

The entire hatching process of fly pupae, from egg to adult fly, generally lasts 10-20 days.

• Egg Stage: Lasts for 1-2 days.
• Larval Stage: Takes approximately 3-9 days to complete.
• Pupal Stage: Lasts for 6-12 days.

Here is a comparison table outlining different stages of fly pupae development:

During the pupal stage, fly pupae undergo metamorphosis and eventually hatch as adult flies. The timeline for hatching can be affected by environmental factors such as temperature, humidity, and food availability. Maintaining optimal conditions can ensure successful and timely hatching.

Reproduction and Development

Mating Process

House flies have a relatively short lifespan, and their reproduction process is quick. Males and females mate in flight, with the male grasping the female from behind using his modified legs. The process is brief, usually lasting only a few minutes.

Laying and Development of Eggs

After mating, female house flies search for suitable organic materials to lay their eggs. Common sites include compost, manure, or even a corpse. The eggs laid by a female house fly are about the size of grains of rice and will hatch in 12-24 hours.

Once hatched, the larvae, commonly known as maggots, emerge as small, white insects that feed on the surrounding organic material. Their primary purpose is to grow and gain enough energy to initiate metamorphosis.

Molting and Growth

During their development, maggots undergo several stages of growth, each followed by a molting process. The molting process allows them to shed their tight exoskeleton and continue to grow.

Housefly larvae require the right conditions to thrive, including moisture and sufficient food sources. Organic materials like compost, decaying fruit, and animal waste provide ideal conditions for their growth.

After 3-8 days, a mature larva will pupate, forming a brown shell-like case known as a puparium. In this stage, the housefly undergoes its final metamorphosis, transforming from a larva into an adult fly. The posterior spiracles, used for respiration, are visible on the puparium.

Fly pupae take about 2-6 days to hatch into adult house flies, depending on the environmental conditions. Once emerged, adult house flies are fully developed and ready for reproduction.

Environmental Conditions and Habitats

Preferred Habitats

Fly pupae are commonly found in areas where there is abundant food and moisture. Some examples of such habitats include:

• Garbage: Decaying organic matter in trash provides a rich source for adult flies to lay eggs.
• Fruit: Fruit flies thrive on overripe or rotting fruits, which have high sugar content.

Role of Temperature and Moisture

Temperature and moisture are two critical factors in determining the duration of the fly pupae stage. In general, warmer temperatures and higher humidity levels accelerate the development process. However, the optimal range may vary depending on the species.

House flies and fruit flies both share the following preferences:

• Warm temperatures: Development is faster at temperatures between 70-90°F (21-32°C).
• Moisture: Larvae require moist environments to survive, as they breathe through their spiracles.

Here’s a comparison table of house flies and fruit flies:

Fly pupae can pose risks to public health by spreading pathogens. Adult flies emerging from pupae after developing in contaminated areas may carry disease-causing agents. Therefore, proper sanitation and waste management are crucial in minimizing the presence of fly pupae and preventing the spread of diseases.

Fly Control and Prevention

Fly Traps and Repellents

Fly traps and repellents are effective ways to control flies around human spaces. The most common fly traps include:

• Sticky tapes
• UV light traps
• Baited traps

Some pros of fly traps are:

• Easy to use
• No chemicals involved

Cons include:

• Unsightly appearance
• Limited effectiveness for larger infestations

For repellents, you can use commercially available products or natural remedies like:

• Citronella oil
• Lavender oil
• Eucalyptus oil

Sanitation and Hygiene

Good sanitation and hygiene practices prevent flies from laying eggs and reduce the number of fly pupae that can hatch. Simple steps include:

• Regularly clean and dispose of trash
• Keep food covered and stored properly
• Seal cracks and openings in walls and windows

By following these steps, you can prevent flies from accessing the environment they need for their stages of development, reducing their lifespan and the number of female house flies.

Taking a combined approach using fly traps, repellents, and maintaining good sanitation can help control pests and make spaces more comfortable for humans to live and work in.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Fly Larva found in Toilet

Subject: Weird worm swimming in toilet
Location: North Carolina
June 23, 2013 7:58 am
I woke up one morning and found tuis thing swimming in my toilet. This was BEFORE I used it! I have looked all over the Internet and can’t seem to find anything like it. It is rather flat, appears segmented and has a beak like protrusion on one end. It is literally swimming around in the water. I just moved into my place in February and am on a septic. Could it be something from that? Hopefully it didn’t come from inside my spouse!! We live on a coastal region of south eastern NC.
Signature: Grossed out on North Carolina

Dear Grossed out on North Carolina,
This is a Fly Larva, though we cannot say for certain which family.  Many Horse Flies have aquatic larvae, but this does not look like a Horse Fly Larva.  It looks most like a Soldier Fly Larva in the family Stratiomyidae.  See this image on BugGuide.  Your guess that it came up the drain from the septic tank is very possible.

Letter 2 – Fly Maggot from the Philippines

This is a bit gross
Location: Malapascua, Visayas, Philippines
December 28, 2010 11:23 pm
So, I admit this is a gross way to discover a new bug, but here goes.
So I’m currently vacationing on Malapascua, a small island in the Philippines.
I was in the toilet, doing my thing, and when I finished I stood up to flush and this thing was in there wriggling around.
At first I was terrified that it was some parasite or something that had come out, as it were. But now I’m thinking that’s impossible, it’s just too big. Still, I was completely freaking out, hence the fishing and photographing.
What is this thing? The white debris on it is…err… toilet paper.
Signature: Sorry…

Dear Sorry,
This appears to be a Fly Maggot, but we have no theories as to why it was found in the toilet.  Though certain flies are parasites, Maggots are not known to be internal parasites within the human gastrointestinal tract.

Karl believes this is a Soldier Fly Larva
Hi Daniel and Sorry…
This is just a thought, but it looks a lot like a Soldier Fly (Stratiomyidae) larva, perhaps even a Black Soldier Fly (Hermetia illucens), also known as the Window Fly. The species is native to southeastern USA but it is also widespread in the tropics, including the Philippines. There are quite a few pictures of larvae, pupae and adults on the WTB? site if you do a search. Black Soldier Fly maggots have become quite popular with people interested in composting and manure management (with some interest developing in the Philippines), and in parts of the world they are also raised as feed for fish or domestic fowl. I found this site that promotes the culture of the maggots for Swiftlet farming in Malaysia (as in harvesting bird nests for soup). It could be some other species but I think this is getting close. They apparently crawl around quite a bit when they are looking for a place to pupate so perhaps that is how this one blundered into the toilet. By the way, I believe this individual has its rear end facing the camera so the toilet paper would be appropriate. Regards. Karl

Letter 3 – Fly Puparia

pantry beetle?
In my bedroom along the floorboard, underneath a window, about 20 of these, ranging in color from light white/yellow to dark brown red. At first I thought it was rice, till i picked one up with tweezers and squeezed it. Big mistake. I live in an apartment that recently had big time exterminators out for Carpenter ants. Since then, no ants, but now this? and in my bedroom? what can I expect? The house is very old, split into apartments so I am use to bugs of all sorts, but these, I don’t know, the fact that I found them in my bedroom, I am a little freaked out. Thanks in advance.
Stephanie

Hi Stephanie,
The good news is you do not have Pantry Beetles. The bad news is you will soon have a Fly invasion. It looks like Flies got into rotting organic matter somewhere (Forgot to take out the garbage? Dead mouse in the walls?) and laid eggs. The maggots developed unnoticed and some wandered to a dry place to pupate. You have Fly Pupae, or more correctly, Fly Puparia.

Letter 4 – Maggots in the Kitchen

What are the larve all over the kitchen floor ?
October 5, 2009
Hi, about once every couple of months we get this spread of larve crawling all over the kitchen ceramic floor. They don’t seem to be coming from the pantry, but we have found the grub making their way into a bag or raisens in the pantry but not much more. The also seem to like to congregate near the bottom of our dirty broom ( do they like grease ?). What is their insect form ?
Geoff Brimhall
San Diego, CA

Hi Geoff,
These fly larvae are Maggots, and they feed on decomposing organic matter, perhaps in the kitchen garbage can.  Try emptying the trash more often to see if this curbs your problem.

Letter 5 – Maggots

Weird worm
Location: western nevada
November 2, 2011 11:22 am
Hi, I’m wondering what this worm is. I found them inside a pumpkin and can’t identify them. please help.
Signature: Nate Dimitroff, Amateur Entomologist

Hi Nate,
Your request did not indicate if these Maggots were found inside a pumpkin that was cut into, or if they were found in an already carved Jack-O-Lantern that was beginning to rot, which is our suspicion.  Flies are attracted to organic matter that is rotting and if conditions are right, the Maggots that hatch from the fly eggs will develop quickly.

Letter 6 – Fly Larvae we believe

What is this mystery bug?
Location: New Mexico, not Colorado Springs
December 3, 2011 11:38 am
Hello there,
Please can you help me identify this?
Thanks,
Gillian
Thanks – by the way the bug was found in New Mexico, not Colorado as stated 🙂

Hi Gillian,
Can you provide any additional information?  What habitat were they discovered in?  We believe these are some type of Fly Larva, but we would like to eventually provide a more specific identification.

Letter 7 – Maggot

Subject: What is this thing??
Location: South Florida
November 23, 2015 7:55 am
Please help me figure out what type of bug this is. I’m assuming it’s in larval stage. The ants that have taken over my home were attacking them while they crawled out of the bottom of a dusty closet and I want to make sure I’m not providing an environment for them to thrive or whatever they do.
Signature: Freaked out in Florida

Dear Freaked out in Florida,
This looks like a Fly Maggot to us.  Maggots often wriggle away from where they are feeding to find a drier location to undergo pupation.  Maggots often feed on putrifying organic material.  People often find Maggots when they forget to take out the garbage or if some food is left rotting, forgotten in the home.  Maggots will also feed on dead animals and it is possible that something died in the walls.

Thank you! I have never seen them at this stage before and was totally freaked out but I didn’t want to kill them until I knew what they were. However, after I asked you I did discover that indeed something had died in the crawlspace so at that point I knew what they were and the maggots were dropping out of a crack from the crawlspace to the closet. Seriously disturbing…I love most bugs, spiders in particular, but these guys turned me into a huge wimp! Thank you so much for your timely response!

Letter 8 – Fly Pupa

Subject: What is this?
Location: Sacramento, ca
January 18, 2016 11:22 pm
This past week we keep finding these outside our front door, and only at night. It doesn’t have legs, it does have weird black stuff at one end of it, everyone says it looks like a larvae or something but they move like a caterpillar.
Signature: Kaitlyn

Dear Kaitlyn,
This looks like the immature stage of a fly, a larva or a pupa, similar to this Black Soldier Fly larva on BugGuide.  Is there a nearby compost pile?

Letter 9 – Maggots

Dear AH,
A couple of years ago I think Jerry Seinfeld did a monologue about baby pigeons. “Why don’t you ever see them?” Well I took it as a kind of challenge; similar to when I was a kid my grandfather said he’d give any of us 5 bucks if we spotted an Idaho license plate. Years later I finally saw an Idaho license plate, but my grandaddy had died by then. But I digress. I have seen baby pigeons. In fact, I now see them all the time. I also seem to see Idaho license plates all the time now too. Now I’m not sure if it’s because I know empirically that they exist that I see them all the time, or maybe I previously suffered from a blind spot; like when you’re looking for the orange juice in the fridge but you can’t fucking find it cause it’s right in front of your nose. But what I’ve been wondering for years and never verbalized until now (because you have this great forum about bugs) is: Where do those fully grown, huge flys come from? I woke up the other morning, I hadn’t opened the doors or windows, I had no trash in my garbage, no turds on the floor, but I had a dozen HUGE houseflys buzzing all around my windows trying to get out. Inga (my dog) and I went crazy–me with the New York Times, her with her deadly snapping jaws–hunting them down and squarshing them until they were dead. It took a while. We were both hot and panting. Now I’m thinking I have house hygene issues. Maybe a blind spot. I just thoroughly cleaned my house the day before the “hatching” because a writer was coming to interview me for the magazine Dwell so I’d better have a tight-assed, spotless abode. So my question is, am I missing something? I know maggots are small, so are tadpoles, but at some point they’re little frogs. So wouldn’t those fuckers be little flys before they were the huge, unhygenic, buzzing bastards? Can you explain?
—David M
Brooklyn, New York

Dear Sir,
Flies are generally thought of as one of the great scourges to afflict mankind. Though certain species deserve that reputation, many others are beneficial insects, like flower flies. I doubt that those buzzing around your windows belong to the latter group, but I am unable to make a positive I.D. on their actual species based on your description. Are they black, green or blue? My grandmother always claimed that cooking cabbage caused flies to enter the house. Have you been cooking cabbage? Not wanting to diverge from your immediate questions, I can safely tell you that all flies undergo complete metamorphosis. While they are maggots at one point in their lives, they pupate and emerge as fully grown flies, attaining whatever size is particular to their species. They often go undetected until they reach that adult buzzing phase. I once had an invasion, and a closer inspection of my rather messy cottage revealed some potatoes under the sink that had gone bad. The culprets in your house could also be carrion eating flies that as maggots had been feasting on a dead rat in the walls or perhaps your next door neighbor. When was the last time you saw your neighbor? Often after feasting on their food source, the maggots will migrate some distance to find a safe and dry refuge for pupation. The filth you seek might be a considerable distance from your infestation. The duration of the metamorphosis varies with the heat. If you didn’t succeed in dispatching all the buzzing Muscidae (hopefully they were not Sarcophagidae, the flesh flies) before a few mated and laid eggs, and the weather is warm, you can expect a reinfestation within a week or two. Be forewarned that Hogue writes in in groundbreaking book, Insects of the Los Angeles Basin, that “flies are known to accumulate around natural gas leaks. They are probably attracted by ethyl mercaptan, a smelly substance added to gas to make leaks detectable to the human nose. The odor of ethyl mercaptan is similar to that of volatile substances released during the decomposition of carrion, upon which many domestic flies oviposit and their larvae feed.” Don’t light any matches until you have sufficiently inspected your entire home.
Signed,
Daniel Marlos

Dear What’s That Bug (or should I say What’s That Maggot?!)
It’s true! The worst homebody kitchen nightmare is occurring in the UK. Maggot-y larvae-like creatures that sloth their way onto my kitchen floor late at night when no one is around. Seven the other night!
Before casting dispersions on the quality of home-maintenance at my flatshare, I must assert that despite my previous track record, cleanliness is next to both god and the queen mum here in my house now, and there are no bits on the floor or on any cabinet surfaces to attrack the offputting vermin. High standards have been maintained. And though I have visited the countryside in the last two weeks, there seems to be no sign of foot and mouth infection either. We have conducted a cursory sniff test and have no evidence of dead rotting flesh behind the cupboards, though they seem to gather in the floor corner and appear to be coming from behind the floor cabinets. What are the possible causes? and cures, short of yanking out all the cupboards and seeing what may lurk behind door number one. help!
Staying out of the kitchen at night in London,
Kate

Dear Kate,
Once again pestilence rears its ugly head. The house fly and its larval form, the maggot, is a truly domestic insect, so closely adapted to life in manmade environments that it is rarely found away from human habitations. The species, Musca domestica, is found throughout the world and is our worst pest among the flies. All kinds of decaying and fermenting organic material — commonly decomposing lawn clippings, gargage, and feces of dogs, cats, horses, rabbits, and poultry — provide breeding places for the larvae. The larvae migrate to drier places for pupation to occur, and it is possible that your clean flat is on their migration route. Maggots are also commonly found on dead and decaying animals. Due to the meat embargo, there are probably huge caches of decaying livestock scattered about the country. Is it possible that your flat is in close proximity to one of these toxic dumps? My other thought is that though you called the creepy-crawlies "maggot-y larvae-like creatures," you never gave me any other description regarding size and coloration. Most insect larvae are generic in form, hence the lumping of many species under the umbrella term. More specifics could be helpful. A caterpillar is a larva, but with true and pseudolegs to aid in locomotion. Beetle grubs are also "maggot-y" and many beetles bore into wood. Certain kinds of moths and beetles have larvae that are fond of flour products and often infest sacks of flour or oatmeal, or even spices that are stored away in dark cupboards. The last time I tried to use my imported Hungarian paprika, I discovered it to be ground zero for the meal moths that have been fluttering about my incandescent lamps at night, and promptly disposed of the tainted (and expensive) spice lest the infestation spread.
Good luck.
Daniel Marlos
What’s That Bug?

Letter 10 – Maggots found in Artichoke Stems in the Pacific Northwest

Subject:  Unknown insect
Geographic location of the bug:  Pacific Northwest
Date: 03/18/2019
Time: 08:31 PM EDTYour letter to the bugman
Early spring: I found many of these inside the rotting stem of my artichoke plants. They’re less than 1/2 inch on length, are legless,  and move a little like a caterpillar but with much less flexibility.
How you want your letter signed:  a gardener

Dear Gardener,
This is most certainly the larva of a Fly, generally called a Maggot, and our best guess at this point is that it is the larva of Terellia fuscicornis, a species of Fruit Fly pictured on BugGuide that feeds on artichokes.  Alas, we have not been able to locate any images of the larvae.  Bug Safari has additional images of the adult Fly.