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The Bluebottle Fly

The bluebottle fly is a domestic pest. It is also known by its Latin name Protophormia Terraenovae. It belongs to the family Calliphoridae. The species is widespread throughout Europe. What makes this fly stand out from your ordinary house fly is its abdomen. It is light blue in colour and has an unmistakable metallic glaze. Those are the knights of flies. They have short antennas, that won’t tangle while the flies ramming their chests in battle.

They have four tarsi per leg and they even have spiked armour to protect them in battle! Those are the key markings of the blue bottle fly that distinguishes it from other species. However, it does look a bit like the green bottle fly and it could be mistaken if you see it under direct sunlight or if the fly is in mid-air. Once it lands, however, your confusion will be gone. You can clearly see the colour, once the fly is in one place.

Blue Bottle Fly Eggs and Maggots

Gross smells are what attracts adult bluebottle flies. Why? Because the smell is a sign that tells them something is rotting away. They lay eggs in dead animals, faeces, any rotting organic matter.

The eggs will soon (2-3 days) hatch into bluebottle fly maggots. They will start eating their way out and will be fully grown in about three days. The maggots then hide in the soil or somewhere else dark and with high humidity, like inside your bin or under the kitchen sink.

The maggots will pupate into cocoons. After two weeks, your brand new batch of bluebottle flies would be ready to cause trouble.

How Your Home Get Infested With Bluebottle Flies

The infestation of your house usually starts from your basement or attic. Sometimes from electric systems, garden compost bins and others. In other words, anywhere that a dead animal can be, or wherever there is any organic matter disintegration going on.

Poisoned rats die in the basements, birds can die on your roof or attic. Organic matter is rotting in your garbage bin and in your compost bin. All those are ideal places for a bluebottle fly to lay its eggs in.

The Dangers of Infestation

This pest is hard to get rid of, mostly because they usually stick in groups and communicate with each other. Once a single fly gets the scent of food, it will contact the others using a pheromone and will rush to the coordinates. We have already mentioned that those are the knights of flies. They are bigger and stronger than your ordinary house fly, and those are pretty hard to get rid of.

The bluebottle fly also lays its eggs in human food! Now, this is where it gets repulsive! This is a serious health risk! The very landing of those flies on your food can transfer bacteria. You already know what is attracting them, so you can imagine the gross things their legs have touched before landing on your meal. The human body has its ways of dealing with most of that bacteria, but still, there is also the “disgust” factor. The slight chance that this fly may carry “something else”, like the Salmonella Typhi, is also disturbing.

Swallowing the eggs of a blue bottle fly can lead to myiasis. Myiasis is the infestation of your body with fly larvae. This will make you the host of the larvae and it will grow inside of you and feed off your tissue.

The worst thing is that bluebottle flies can turn other pests into vector agents. Vector agents are the insects or surfaces chosen from the bluebottle fly to transmit their larvae to you. In other words, she can hire another insect to infect you, or just set a trap. Those vector agents can be anything – from common house flies to even moist dirt. The blue bottle fly can infest a human being even without any open wounds. Usually, flies that are capable of myiasis prefer filthy tissue or open wounds. However, this fly knight can do it all.

Blue Bottle Fly Facts

Blue Bottle Flies and Hibernation

This fancy flying menace usually hibernates during the winter. However, if the fly finds a warm place to continue feeding and reproducing, it will gladly take on the offer. Open windows and doors to human homes are the invitations the fly waits to receive. It can also get inside through cracks or just lay its eggs there in order to save them. Once in your beloved home, it will lay eggs around and will annoy you until it gets the better of you and provokes your rage.

What Do Blue Bottle Flies and Bees Have in Common?

Bluebottle flies are actually pollinators. This means that they help flowers and plants to breed, just like the hardworking bees. There is a big difference, however. Bees prefer plants with pleasant smells. Flies, on the other hand, pollinate plants like “Dead Horse Arum”, “Golden Rod” and last but not least “Skunk Cabbage”. And yes, it does deserve its name. The stench and appearance of those grotesque flowers are what invites flies to pollinate them.

Reproduction Facts

All of the bottle flies (blow flies) feed on the nectar of flowers in order to make their eggs even stronger. A female can lay around 2000 eggs in her lifetime (around 6 weeks). Those eggs will hatch pretty quickly, around two days if the moisture level is right. The larvae hatched from the eggs can get up to 20 mm in length.

Bluebottle Fly Facts in Numbers

  • The eyes of the bluebottle fly are made out of 8000 facets.
  • The bluebottle fly can smell things 750 yards away.
  • A bluebottle fly can travel 300 times the length of its body in a single second.
  • The wings of the fly move at a rate of 200 times per second.

How to Get Rid Of Bluebottle Flies

They are still flies! Yes, bigger and badder, but still flies. Insecticides are what gets them. They also have the same habits as an ordinary housefly. So, they will fall for sticky surfaces and homemade traps.

Always be mindful of the Myiasis and the bacteria they are carrying. The presence of those flies in your property bares some health risks, action must be taken swiftly.

Install fly traps around your home and don’t leave food with no cover on top, at least till you limit the population of the flies.

If you have any doubt about the presence of a blue bottle fly, better call a specialist to investigate. Better safe than sorry, right?

A specialist can examine the property and use the best insecticides to counter all stages of the fly evolution. In other words, kill adult flies, larvae, and eggs. If the infestation is severe, it may need a heat treatment, from which flies have no chance of escaping.

27 Responses

  1. Avatar Stephanie Farham says:


    A family member has bluebottles flies coming out from a crack behind their fire. They did have a gas fire but now it’s been blocked with bricks. The flies are coming out from a small crack. They have sprayed with fly killer. If they sealed the crack would that sort the problem.

    • It would be great if there is a way to check where this crack is going.

      I assume that there is no way to do that, without the help of a handyman… It will most likely involve the removal of a couple of bricks.

      Sealing the crack may resolve in:

      A: trapping the flies there and killing them.
      B: forcing them to find another way out.

  2. Avatar Kirsty Grimshaw says:

    Hi there…. Are you aware of there being a HUGE number of greenbottles at the moment?! Due to the heat?! This is our first summer in this house and there are literally hundreds of them in the garden…. I have large fly traps and am trapping hundreds in a matter of a few days?! I can’t find anything dead in the bushes or anything?! Just wondering what else I can do…. Thanks

  3. Avatar Montserrat says:

    We have just returned from our holidays and found more than 50 dead bluebottle flies in various places in our house, mainly downstairs, not in the bedrooms. We cannot think of anywhere that they could have come from as all the windows were closed. We have also checked for vents, fans in bathrooms and other possible ways in, but cannot find anything. We have even checked for any dead rodents, but found nothing. Any suggestions?

  4. Avatar Rebecca Shrubb says:

    Hi we have had numerous bluebottles in our upstairs area of the house. After investigation we have narrowed it down to the attic area. My husband is going to try and search attic to see if he can find the source we have spray and dettol speay to clean is there any thing else we can do ??

  5. Avatar Geoff Frampton says:

    Decades ago bluebottles seemed to be everywhere and I don’t really remember seeing greenbottles back then, but in the last few years I have seen only greenbottles, not bluebottles. A few friends and colleagues noticed the same. Are you seeing any general patterns in the numbers of greenbottles versus bluebottles and if so are there any explanations you’re aware of?

  6. Avatar Eltringham says:

    How do you treat maggots and eggs round a pet rabbits bum?

    • Ahm… We don’t treat rabbit bums, to be honest. 🙂 You will have to clean it regularly. Also, block entryways of flies to inside your home and discourage them from staying.

      We can treat your property, but not your rabbit 🙂

  7. Avatar Laurie Barker says:

    Hi. I keep finding young blue bottles in the house. I’m guessing they are young as they are easily caught.
    No dead animals lurking or food laying about. House is clean. For the life of me I can’t find where they are coming from. Its driving me nuts now after 4 days of it. Usually about 6 to 7 per day.

    • Avatar Stanza says:

      I have the same problem. Finally found and removed a dead mouse the cat had brought in, then scrubbed and disinfected the area. Flies still appearing – some don’t even have their wings yet.
      Was mystified until I saw one crawl out of a tiny crack in the skirting board. There must be pupae/cocoons in there. Hoping that eventually they all will have hatched and there will be no more, as not keen to take the skirting board off. I could block the hole but tbh would rather they all came out than have them dying in there – yuk…

  8. Avatar Laurie Barker says:

    The question someone asked about rabbits bums and maggots. It cleaning the cage and the rabbit regularly to prevent it 🙂

  9. Avatar Ray Dell says:

    I keep getting one bluebottle in my attic bedroom every couple of weeks. The problem is that pidgeons nest on my roof too. Could these be the source of the lone bluebottle? While it’s not an infestation getting the odd bluebottle is baffling me.

  10. Avatar Trish says:

    Hi please help I have had bluebottles appear in my house as soon as I kill 1 another will appear. Where they are coming from beats me as I cannot find any evidence of a bad smell or food laying around.
    This has been going on since December I have killed at least 20 of these nasty things.
    It’s stressing me out

    • Amber Morris Amber Morris says:

      Check your basement and loft. Be thorough around corners and see for any cracks or other openings through which flies can enter. During the winter they enter our homes for the warmth, so foul smells and decaying matter are not their priority.

  11. Avatar Chlo says:

    One adult large fly keeps appearing in my living room and I don’t have a clue where there coming from it’s cringing me out my house is clean no dead matter or foul smells help !!

    • Amber Morris Amber Morris says:

      Please, check the answer I gave to Trish. If you can’t spot the origin you may want to call in a professional to inspect. I can only assume that you are seeing flies that were lucky enough to find an entrance to your cosy home, not an infestation.

  12. Avatar Julie chater says:

    I have been invaded with mice and rats , have had pest control round where they just put the poison behind kitchen plinths and loft , all cracks in the brickwork have been sealed and iv not had any more rats or mice for a couple of months, however, a few weeks ago I noticed blue bottle flies in the house, they were almost dying, over the next few days I was seeing up to 25 blue bottles dead on various windowsills, mainly the bathroom, kitchen and living room, I have sprayed every room with fly spray 4 or 5 times a day, but they are still coming , there is no smell of a dead rodant in the house, there is no rubbish or food on display, bygone keep finding as many as 25 even more b.b every day, I can’t figure where they are coming from, I have sealed the vents, been in the loft where the rats were nesting, again no smell, no flies up there , in the spare bedroom there was hundreds of them dead on the windowsill , that’s just a storage room, no food in there and again, .no awful smells in there, it is driving me crazy , i have gone from searching for vermin now I’m fly searching , it’s never ending , can anyone advice me what I can do, the only thing I can think of is there’s a dead rodant in the cavity walls but how do I get to that it’s impossible, do I just have to ride this out t they eventually all die ??? Desperate ….

  13. Avatar Juliet Hyslop says:

    Hi. Hope you can help. I have had an infestation of bluebottle flies in house last few weeks. Have tried everything. Eventually got professionals in to treat the source that was in the attic. That was three days ago but we are still getting bluebottles although not as many. I thought the professional spray would have done the trick. We are using spray in the house to try to contain the present ones. Is this normal to get some after treatment done and what’s the best way forward now.

    Kindest regards

    • Amber Morris Amber Morris says:

      Chances to deal with any infestation with a single visit are slim. Except maybe wasps, but that is a different story. The professionals here at 24/7Pest Control make at least two visits. One for an initial treat and a follow up, if the client sees any signs of pests.

  14. Avatar Hananh says:

    Hi. Today I have returned to my parents house after a few weeks away and have had to get rid of 10 bluebottle flies from inside the house within one day! 10! They are all unbelievably dopey and barely even responsive when you hit them or try and get them to fly away. They are found in multiple different rooms throughout the day and when I think I can’t find any more.. then boom.. one more… and then another! I know my parents have probably had the windows and doors open because it is hot outside and maybe do not notice them because they are both older… but 10 flies?! I wasn’t that concerned when it was 3-4 but as it’s gotten more and more throughout today 10 is so many! I was wondering if this was an infestation? Or how this was happening? What might be causing this? If you know why they might be stuck in the house? I’m praying they will stop appearing but it’s so strange because they are so dopey and unresponsive but there are so many I am confused! Any help would be amazing.

    • Avatar Danielle says:

      Hi, we had this issue when we lived in our flat and turned out to be dead rat under the floor boards! I’ve just had a new kitchen installed were they blocked off a chimney but not at the top – I have about 10-20 blue bottles a day just now in the kitchen, something has clearly died and it’s decaying – this will be where the blue bottles are coming from but can’t get to it!

  15. Avatar Claire says:

    I’ve had 12 bluebottles today so far. They are all pretty slow and dopey. We have a room that is full of building material, bikes and clothes but no food (waiting on renovations). Could the bluebottles have spent the winter in the house and are now waking up? All doors and windows have been closed. We live in the countryside so used to dealing with loads coming in through windows and doors usually. I can’t stand them!

    • Amber Morris Amber Morris says:

      ” Could the bluebottles have spent the winter in the house and are now waking up ” That would explain their “dopey” behaviour. Are there any painting supplies in that room? You are mentioning building materials, maybe some vapours are effecting the flies as well. In some cases, animals infested with larvae enter our properties and die somewhere between walls or in chimneys and later on spread the bluebottle infestation. Note that while you are renovating that storage room.

  16. Avatar Sandra McGregor says:

    I have a very big problem with bluebottle flies.
    I have a very big green bush called PLATYCLADUS ORIENTALIS and it has bluebottle flies on it but there is a very strong smell is coming of the bush and it doesn`t have flowers on it only this round balls for these kinds of native bush. I have a good look under and in the bush and I didn`t see anything dead.

  17. Avatar Sharon Wood says:

    I had my gas fires serviced yesterday and now have an infestation of bluebottles. Could they have been hibernating behind the fire, which hasn’t been used for over a year, or in the chimney and have been disturbed? The gas man said he never noticed a dead bird or anything.

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