Bristle Fly: All You Need to Know for a Bug-Free Life

Bristle flies are a fascinating group of insects known for their unique features and behavior. These insects are part of the family Tachinidae, which comprises around 8,200 known species worldwide. Bristle flies are named for the distinctive bristles that cover their bodies, providing a clue to their identity.

One of the roles of bristle flies is their contribution to the ecosystem as parasitoids. They lay their eggs on or in other insect hosts, and their larvae eventually consume the host from the inside, killing it. This makes them valuable in controlling pest populations, such as caterpillars, beetles, and aphids, offering great potential for biological pest control methods.

Interestingly, some bristle flies are also pollinators. Adult flies consume nectar from flowers and can help in the pollination process. Their presence and importance in various ecosystems make understanding bristle flies an essential topic.

Bristle Fly Basics

Identification and Characteristics

Bristle flies belong to the family Tachinidae in the order Diptera, which also includes house flies. They can be easily recognized by the following features:

  • Bristles covering their body
  • Large eyes
  • Resemblance to house flies

Similar to other insects, adult bristle flies have three main body sections: head, thorax, and abdomen.

Size and Color

Bristle flies can come in varying sizes and colors, depending on the species. For instance:

  • Some species are small, similar to house flies (less than 3⁄8 inch in length)
  • Other species can be as large as 1 inch in length
  • Colors range from black, brown, to metallic

Distribution and Habitat

Bristle flies can be found across the United States and in other countries as well. These insects inhabit diverse environments, such as:

  • Forests
  • Meadows
  • Urban areas

Now you have a brief understanding of the bristle fly’s basic identification, characteristics, size, color, distribution, and habitat.

Bristle Fly Life Cycle and Behavior

Development and Stages

Bristle flies undergo a complete metamorphosis, with four developmental stages: egg, larva, pupa, and adult. The larval stage, also known as maggot, is the main feeding stage of the insect. They transform to pupae, immobile and non-feeding, as they develop into adults.

Feeding Habits

Bristle flies have diverse feeding habits. Adult flies mainly feed on nectar and pollen, while larvae feed on various insects like:

  • Aphids
  • Caterpillars
  • Grasshoppers

Some species of bristle flies even act as parasites or predators, feeding on bees, beetles, and ants.

Mating and Reproduction

Mating in bristle flies involves the male placing a sperm packet into the female’s reproductive tract. After fertilization, females lay their eggs on suitable hosts or substrates, such as decaying organic matter or on the bodies of other insects.

Predators and Pests

Bristle flies have numerous natural enemies, including:

  • Spiders
  • Predatory beetles
  • Other kinds of flies

These predators help to control bristle fly populations in different regions, such as Wisconsin and Canada. Occasionally, bristle flies may cause infestations in households, and getting rid of them can be achieved by eliminating their breeding sites.

Bristle Fly Features

  • Bristles on the body
  • Two wings with distinct venation
  • Short antennae

Bristle Fly Characteristics

  • Robust or slender body shape
  • Wide color variation
  • Pollinators for some plant species

Pros and Cons of Bristle Flies

Pros

  • Contribute to controlling pest populations
  • Act as pollinators for some plants

Cons

  • Can cause infestations in homes
  • Some species are biting flies

Comparison Table: Housefly vs. Bristle Fly

Characteristic Housefly Bristle Fly
Size < 3/8 inch 1/8 to 1 inch
Appearance Dark, no bristles Bristles, colorful
Feeding Decaying matter Nectar, pollen, insects
Role Transmit diseases Pollinators, pest control

Bristle Fly Interactions with Humans

As Pests and Infestations

Bristle flies are considered pests because they can bite and bother humans, especially in outdoor settings. These insects are often attracted to human activities and events such as picnics, barbecues, or upcoming events listed on a calendar.

Some common issues with bristle fly infestations include:

  • Bites causing irritation and discomfort
  • Buzzing around and annoying people during outdoor events
  • Landing and crawling on food or surfaces, potentially spreading germs

Dealing with Bristle Flies

There are various strategies to deal with bristle flies. Here are a few examples:

  • Use insect repellent on exposed skin and clothing
  • Install bug zappers or fly traps in affected areas
  • Ensure proper sanitation and waste disposal to reduce fly attraction

For even more information, consider checking out online forums where people discuss their experiences and successful methods for dealing with bristle fly infestations.

A comparison table of common methods to deal with bristle flies:

Method Pros Cons
Insect repellent Easy to apply Needs reapplication
Bug zapper Continuous protection Needs electricity
Fly trap Chemical-free Limited coverage

By understanding bristle fly behavior and using the appropriate methods, humans can minimize the impact of these pests on their lives and activities. Remember, always prioritize safety and cleanliness when dealing with any pest infestation.

Resources and Further Information

Photo Galleries

There are various online resources where you can find high-quality images and photos of Bristle Flies. These photo galleries are valuable for:

  • visual identification
  • studying female and male differences
  • observing various stages in their life cycle

We recommend checking out BugGuide and looking up their taxonomy under arthropods and hexapods / calyptratae.

Online Field Guides

For more in-depth information on Bristle Fly identification and taxonomy, online field guides can be helpful. These guides give you a better understanding of:

  • Bristle Fly characteristics
  • Habitat preferences
  • Behavior

Some field guide examples include the Clickable Guide on BugGuide and the Arthropod Guide on Louisiana State University’s website.

Upcoming Events and Gatherings

Participating in gatherings and events can further expand your knowledge on Bristle Flies. Some notable gatherings are:

  • BugGuide Gathering: An annual event where arthropod enthusiasts meet to learn and share information. Upcoming gatherings include Spring 2021 in Virginia and New Mexico. More details here
  • National Moth Week: A global event focused on moth appreciation and education. Bristle Flies might be a topic of interest during these events. Check their website for more details.
Event Time Location
BugGuide Gathering (Spring 2021) Spring 2021 Virginia
BugGuide Gathering (New Mexico) TBD New Mexico
National Moth Week Annually Worldwide

Ways to Support

If you’re interested in contributing to Bristle Fly research and conservation efforts, consider donating to organizations like BugGuide. Their donation page provides more information on how you can support their cause.

Contributors and Acknowledgements

We are grateful to various naturalists who shared their expertise and knowledge about Bristle Fly, making this article possible. A special thanks to John F. Carr for his valuable insights and guidance.

Our platform encourages users to register and participate by adding comments to enrich the conversation around these fascinating creatures. We thank both expert professionals and enthusiastic amateurs for contributing to this article.

To ensure accurate information, we highly recommend seeking expert professional advice from your local extension office for specific information and assistance.

Please be informed, this article serves as a general overview of the Bristle Fly, and the information presented is not a substitute for professional consultation.

Characteristics of Bristle Fly:

  • Body covered with bristles
  • Diverse colors and sizes
  • Common in various habitats
Comparison Bristle Fly House Fly
Size Varies Less than 3/8 inch
Habitat Diverse Human dwellings
Life cycle Variable around 3 weeks

When using the information from this article, please adhere to the copyright and licensing guidelines, and respect the terms of use and privacy statement on our website.

For a printer friendly version of this article, please visit the provided link.

We hope this article serves as a helpful starting point for those interested in learning about Bristle Fly and the diverse natural world. Remember, registering and participating by adding comments is a great way to share your thoughts and experiences.

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 – Bristle Fly from Australia: Amphibolia vidua

 

Is this a bristle fly
Location: Healesville, Victoria Australia
November 29, 2010 2:53 pm
Hello Bugman, I believe this is a bristle fly going on the photos I’ve seen here. This is only the second of these flies I’ve ever seen here after 13 years of living in the area. It was seen in Healesville, Victoria, Australia on Nov 29th 2010, that’s just a couple of days before Summer.
Signature: Linda

Bristle Fly

Hi Linda,
The first time we posted a photo of this distinctive fly in 2007, we posted it as an unidentified Tachinid Fly.  In 2009, we posted another image, still unidentified, and we eventually learned it is
Amphibolia vidua and the common name Bristle Fly is used for the family Tachinidae, the Tachinid Flies.  You are correct in calling your individual a Bristle Fly.

Bristle Fly

would you like some more photos for your files?  I tried to put them on yesterday but they were all too big.  I’m happy to email them to you if you want them.
Just to give you some more information-  I’ve seen one of these flies once before here, about 5 years ago, it was very sluggish and divebombed me, and in my panic I swatted and killed it.  The black shape on the rump (do flies have rumps?)  was very slightly different to this one, it was a perfect heart shape.  I assume they are the same type of fly and there’s just a bit of individual variation.
Thanks so much for getting back to me, your site is fantastic!
Linda Meerman

Bristle Fly

Thanks for the additional information and photos.

Letter 2 – Bristle Fly from Australia: Amphibolia vidua

 

Subject: Tachinid Fly of Australia
Location: South-East Tasmania
December 14, 2014 8:21 pm
Photo taken 11 Dec 2014, SE Tasmania. Copyright David Irwin, 2014.
Nikon D7100; 150.0-600.0 mm f/5.0-6.3; F.L. 600mm.
My husband photographed this blowfly sitting above the headlight of our car. It was approximately the size of a human thumb. [Ed Note:  This should be thumb nail.] This photo shows great detail in the face of the fly. I have several images, as the fly stayed put, no matter how close we came. Though we couldn’t get too close, because on that occasion, David had the large 600mm zoom mounted and needed to get a few metres away for it to focus. It also had a very deep hum when it eventually flew off (when I went to compare size to my thumb[nail]). However, the one posted here is the clearest. Hand holding a heavy zoom lense is difficult.
This bug website (Whats This Bug) has 2 distinctly different Tachinid Flies (with a striking white band) on file, one is the ‘Bristle Fly’, or Amphibolia Vidua (my photo submitted), and one is the Formosia Specia, which is detailed in this scientific record:
http://biocache.ala.org.au/occurrences/1f1319a4-d231-4b1c-acf2-86627aff3fb9;jsessionid=9203058C513D7BAD7223F7123AD42FA6
Both flies look similar, but there are distinct differences – I have also detailed the two flies in my FB post here:
https://www.facebook.com/tasmanianartist/photos/a.10154934951460015.1073741869.204763860014/10154928182185015/?type=3&theater
with more photos from flickr, and ‘Atlas of Living Australia’.
What I’ve been able to find out is that Amphibolia vidua has 2 black dots on the white band [and even if they join, they still are identifyable as 2], and Formosia Specia has one black dot on the white band, with 2 white extensions towards the fly’s tail. Their eyes are set differently, too. Both occur in Tasmania, and Australian mainland.
cheers from down under
Signature: Marlies

Bristle Fly
Bristle Fly

Dear Marlies,
Thanks for your rigorous pursuit of the identity of your Bristle Fly,
Amphibolia vidua, and also for explaining the differences between this species and Formosia (Euamphibolia) speciosa, another Bristle Fly or Tachinid Fly in the same family.

Hello Daniel
What a journey that was! A fly took charge of almost an entire week! But it was fun 🙂
I must say, I was a little distracted by my heart monitor, and other associated ‘things’, and haven’t exactly paid attention too much whether I made any sense at all – I do apologize if I confused everyone.
My husband photographed Amphibolia Vidua. This is the image I submitted. I then found another image attached to the Australian site ‘Atlas of Living Australia’, of which I posted the link (http://biocache.ala.org.au/occurrences/1f1319a4-d231-4b1c-acf2-86627aff3fb9;jsessionid=9203058C513D7…); THAT image on that site was of the Formosia Speciosa image that I mentioned. (Yes, both are Tachinid Flies, or Bristle Flies – that took a while to sink in with me, as I had no idea that there was any difference between a fly and a fly, before all of this – tho I know there are flies here that look like honey bees, and they wait for honey bees to come along, then ambush and kill them, I’ve observed them do it).
Here is the link to the image details – I think you may be able to link to the photo (which brings the photo up on your site). http://images.ala.org.au/image/details?imageId=b963f524-b62f-494e-bfde-db2b9b04115c
You also have a photo of a Formosia Speciosa (post titled ‘Australian Tachinid Fly appears to be Formosia speciosa’, and it is the one where I posted all of my ‘findings’, and where you replied to my expansive ramblings).
So, you do have both flies; they’re difficult to distinguish, but somehow, by counting the dots, I managed to join them (pardon the pun). And others clearly identify the Amphibolia Vidua – I’ve posted the relevant flickr posts on my facebook thread about the fly …
https://www.facebook.com/tasmanianartist/photos/a.10154934951460015.1073741869.204763860014/10154928
It’s been a real pleasure fiddling with a peculiar blow fly for once, and to leaf through your website – what a treasure trove; great stuff – love it. If I ever come across a bug again that I can’t identify, your website will certainly be my #1 stop.
I hope that you’ll correct my typo, which says the fly is about the size of a ‘human thumb’ … it certainly is not, it is the size of a HUMAN THUMB NAIL – and I did it twice in the same text.
Best wishes to you
cheerio from downunder
Marlies

Letter 3 – Bristle Fly from Australia

 

Subject: Can you please name my bug
Location: Mandurah Western Australia
July 28, 2015 1:25 pm
Can you please identify this little fly
Thank you Tracey Marinkovic
Signature: Just a name

Bristle Fly
Bristle Fly

Dear Tracey,
We are more than prepared to supply you with a response, and we hope you respond to our questions as well.  This looks very much like a Bristle Fly,
Amphibolia vidua, a species in the family Tachinidae from Australia that has caused a bit of confusion on our site in the past.  According to the head of Entomology of Csiro regarding a previous posting:  “Its larvae feed as a parasite internally on other insects.  On sunny days in summer the adults often rest on smooth eucalypt tree trunks, and similar structures such as poles and pipes.”  We also know that adult Tachinid Flies frequently visit flowers.  We are very curious for you to explain why you titled your images “snail parasite” and we hope you can provide us with an explanation. 

Bristle Fly
Bristle Fly

The only reason my bug had Snail Parasite written on it was I seen the pic of one on the Internet and thought it looked like one. I was just guessing cheers and thank you

Letter 4 – Bristle Fly from Australia

 

Subject:  You’re Bristle Fly post
Geographic location of the bug:  Southern Yorke Peninsula S.A
Date: 06/05/2021
Time: 09:25 PM EDT
Your letter to the bugman:  I took these photos in a Flora Park on the 27th of Dec. 2020 in Edithburgh. My home town. Interesting to see all your varieties. I just thought it was beautiful, like a piece of jewellery, all golden.
Only ‘just’ learnt it was a fly– 2 wings.
Please respond with the fly’s official name. Would like to have this submitted in the local newsletter. The photo was taken on my Samsung S5.
Thank you for your time.
How you want your letter signed:  Mrs Charyl Turner

Bristle Fly

Dear Charyl,
We believe your Bristle Fly is
Formosia speciosa.

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 – Bristle Fly from Australia: Amphibolia vidua

 

Is this a bristle fly
Location: Healesville, Victoria Australia
November 29, 2010 2:53 pm
Hello Bugman, I believe this is a bristle fly going on the photos I’ve seen here. This is only the second of these flies I’ve ever seen here after 13 years of living in the area. It was seen in Healesville, Victoria, Australia on Nov 29th 2010, that’s just a couple of days before Summer.
Signature: Linda

Bristle Fly

Hi Linda,
The first time we posted a photo of this distinctive fly in 2007, we posted it as an unidentified Tachinid Fly.  In 2009, we posted another image, still unidentified, and we eventually learned it is
Amphibolia vidua and the common name Bristle Fly is used for the family Tachinidae, the Tachinid Flies.  You are correct in calling your individual a Bristle Fly.

Bristle Fly

would you like some more photos for your files?  I tried to put them on yesterday but they were all too big.  I’m happy to email them to you if you want them.
Just to give you some more information-  I’ve seen one of these flies once before here, about 5 years ago, it was very sluggish and divebombed me, and in my panic I swatted and killed it.  The black shape on the rump (do flies have rumps?)  was very slightly different to this one, it was a perfect heart shape.  I assume they are the same type of fly and there’s just a bit of individual variation.
Thanks so much for getting back to me, your site is fantastic!
Linda Meerman

Bristle Fly

Thanks for the additional information and photos.

Letter 2 – Bristle Fly from Australia: Amphibolia vidua

 

Subject: Tachinid Fly of Australia
Location: South-East Tasmania
December 14, 2014 8:21 pm
Photo taken 11 Dec 2014, SE Tasmania. Copyright David Irwin, 2014.
Nikon D7100; 150.0-600.0 mm f/5.0-6.3; F.L. 600mm.
My husband photographed this blowfly sitting above the headlight of our car. It was approximately the size of a human thumb. [Ed Note:  This should be thumb nail.] This photo shows great detail in the face of the fly. I have several images, as the fly stayed put, no matter how close we came. Though we couldn’t get too close, because on that occasion, David had the large 600mm zoom mounted and needed to get a few metres away for it to focus. It also had a very deep hum when it eventually flew off (when I went to compare size to my thumb[nail]). However, the one posted here is the clearest. Hand holding a heavy zoom lense is difficult.
This bug website (Whats This Bug) has 2 distinctly different Tachinid Flies (with a striking white band) on file, one is the ‘Bristle Fly’, or Amphibolia Vidua (my photo submitted), and one is the Formosia Specia, which is detailed in this scientific record:
http://biocache.ala.org.au/occurrences/1f1319a4-d231-4b1c-acf2-86627aff3fb9;jsessionid=9203058C513D7BAD7223F7123AD42FA6
Both flies look similar, but there are distinct differences – I have also detailed the two flies in my FB post here:
https://www.facebook.com/tasmanianartist/photos/a.10154934951460015.1073741869.204763860014/10154928182185015/?type=3&theater
with more photos from flickr, and ‘Atlas of Living Australia’.
What I’ve been able to find out is that Amphibolia vidua has 2 black dots on the white band [and even if they join, they still are identifyable as 2], and Formosia Specia has one black dot on the white band, with 2 white extensions towards the fly’s tail. Their eyes are set differently, too. Both occur in Tasmania, and Australian mainland.
cheers from down under
Signature: Marlies

Bristle Fly
Bristle Fly

Dear Marlies,
Thanks for your rigorous pursuit of the identity of your Bristle Fly,
Amphibolia vidua, and also for explaining the differences between this species and Formosia (Euamphibolia) speciosa, another Bristle Fly or Tachinid Fly in the same family.

Hello Daniel
What a journey that was! A fly took charge of almost an entire week! But it was fun 🙂
I must say, I was a little distracted by my heart monitor, and other associated ‘things’, and haven’t exactly paid attention too much whether I made any sense at all – I do apologize if I confused everyone.
My husband photographed Amphibolia Vidua. This is the image I submitted. I then found another image attached to the Australian site ‘Atlas of Living Australia’, of which I posted the link (http://biocache.ala.org.au/occurrences/1f1319a4-d231-4b1c-acf2-86627aff3fb9;jsessionid=9203058C513D7…); THAT image on that site was of the Formosia Speciosa image that I mentioned. (Yes, both are Tachinid Flies, or Bristle Flies – that took a while to sink in with me, as I had no idea that there was any difference between a fly and a fly, before all of this – tho I know there are flies here that look like honey bees, and they wait for honey bees to come along, then ambush and kill them, I’ve observed them do it).
Here is the link to the image details – I think you may be able to link to the photo (which brings the photo up on your site). http://images.ala.org.au/image/details?imageId=b963f524-b62f-494e-bfde-db2b9b04115c
You also have a photo of a Formosia Speciosa (post titled ‘Australian Tachinid Fly appears to be Formosia speciosa’, and it is the one where I posted all of my ‘findings’, and where you replied to my expansive ramblings).
So, you do have both flies; they’re difficult to distinguish, but somehow, by counting the dots, I managed to join them (pardon the pun). And others clearly identify the Amphibolia Vidua – I’ve posted the relevant flickr posts on my facebook thread about the fly …
https://www.facebook.com/tasmanianartist/photos/a.10154934951460015.1073741869.204763860014/10154928
It’s been a real pleasure fiddling with a peculiar blow fly for once, and to leaf through your website – what a treasure trove; great stuff – love it. If I ever come across a bug again that I can’t identify, your website will certainly be my #1 stop.
I hope that you’ll correct my typo, which says the fly is about the size of a ‘human thumb’ … it certainly is not, it is the size of a HUMAN THUMB NAIL – and I did it twice in the same text.
Best wishes to you
cheerio from downunder
Marlies

Letter 3 – Bristle Fly from Australia

 

Subject: Can you please name my bug
Location: Mandurah Western Australia
July 28, 2015 1:25 pm
Can you please identify this little fly
Thank you Tracey Marinkovic
Signature: Just a name

Bristle Fly
Bristle Fly

Dear Tracey,
We are more than prepared to supply you with a response, and we hope you respond to our questions as well.  This looks very much like a Bristle Fly,
Amphibolia vidua, a species in the family Tachinidae from Australia that has caused a bit of confusion on our site in the past.  According to the head of Entomology of Csiro regarding a previous posting:  “Its larvae feed as a parasite internally on other insects.  On sunny days in summer the adults often rest on smooth eucalypt tree trunks, and similar structures such as poles and pipes.”  We also know that adult Tachinid Flies frequently visit flowers.  We are very curious for you to explain why you titled your images “snail parasite” and we hope you can provide us with an explanation. 

Bristle Fly
Bristle Fly

The only reason my bug had Snail Parasite written on it was I seen the pic of one on the Internet and thought it looked like one. I was just guessing cheers and thank you

Letter 4 – Bristle Fly from Australia

 

Subject:  You’re Bristle Fly post
Geographic location of the bug:  Southern Yorke Peninsula S.A
Date: 06/05/2021
Time: 09:25 PM EDT
Your letter to the bugman:  I took these photos in a Flora Park on the 27th of Dec. 2020 in Edithburgh. My home town. Interesting to see all your varieties. I just thought it was beautiful, like a piece of jewellery, all golden.
Only ‘just’ learnt it was a fly– 2 wings.
Please respond with the fly’s official name. Would like to have this submitted in the local newsletter. The photo was taken on my Samsung S5.
Thank you for your time.
How you want your letter signed:  Mrs Charyl Turner

Bristle Fly

Dear Charyl,
We believe your Bristle Fly is
Formosia speciosa.

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.

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.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts

14 thoughts on “Bristle Fly: All You Need to Know for a Bug-Free Life”

  1. The CSIRO’s giant tomes “The Insects of Australia” has a colour plate with one of these – but gives it as Formosia speciosa. Annoyingly, I can find no other mention of the species or genus online :/

    Reply
    • Please send the link. A search of Formosia speciosa and CSIRO did not produce any hits. Perhaps the source material you cited was an actual printed volume.

      Reply
  2. d’oh – I shouldn’t have said “other mention online” should have I? Yes, it is actual printed media – a double volume of immense value to Australian entomologists

    Reply
  3. Small correction – of course, the fly is NOT the size of a ‘human thumb’, it is about the size of a HUMAN THUMB NAIL. – typo … I was distracted by the mesmerizing painting on the fly’s backside 🙂
    Marlies

    Reply
  4. In reply to bugman:
    Reference to Formosia speciosa does indeed exist online. Formosia (Euamphibolia) speciosa, in one instance, and Google search for that reveals several more Australian sources. It may have once been treated as the same species, Idk, but is now classified as a different Genus to Amphibolia vidua. In some ways they look similar, but not the same.

    Reply
    • No, but we update comments daily and our editorial staff approves all comments to ensure there is nothing inappropriate.
      Thanks for your research regarding this posting.

      Reply
  5. Hi folks. I have just seen this same dude on my way back inside tonight. I’m in Montmorency, Victoria. It’s blue colouration of the dots caught my eye. I’ve never seen one here so had to try and identify it ….. curiosity and all that! Thanks for having this info. available so I could identify it.

    Reply

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