Do Picture-Winged Flies Bite? #1 Answer

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Picture winged Flies, as the name suggests, are one of the most handsome-looking specimens of their species. But do picture-winged flies bite?

Flies are among some of the most common insects or pests found in our surroundings. Among them are the picture-winged flies or Ulidiidae.

These are small or mid-sized flies similar to and often easily mistaken for a fruit fly. Their sizes vary anywhere between ¼ to ½ inch and can differ from species to species.

Picture-winged flies do not bite and are not a pest for crops or other plants (indoor or outdoor plants). There are multiple species of the picture-winged fly, numbering over 100 in North America.

But what are these flies? Are they harmful? What is their life cycle? We’ll answer all these questions in the following article. Keep reading!

Do Picture-Winged Flies Bite
Picture Winged Fly

What Are Picture Winged Flies?

Picture winged flies or Uliididae of the order Diptera (flies) are called so because of the striking patterns found on their wings. While there are several different species of picture-winged flies, the most common one is known as the Delphinia picta.

Most species, including the latter, have a body shape like that of an ant with a strikingly large snout. They can be recognized by the distinct dark bands in black, brown, or yellow patterns on their clear wings.

A picture winged fly’s life cycle is similar to that of most other insects. It develops from an egg and goes through the larval and pupal stages to emerge as a sexually mature winged adult in 45 days and can live up to two months.

Do They Bite?

Even though there are not many known and reported incidents of picture-winged flies biting humans, there is a rare possibility that they may bite. Insects are known to bite for two major reasons – to secure a food source and as a defense when disturbed or distressed.

Since the picture winged fly is an insect, it may bite. But they’re generally not known to bother humans or pets as they don’t feed on blood.

Are They Poisonous?

Picture winged flies are not known to be poisonous. These flies are neither known to attack humans or pets nor do they transmit any kind of diseases. Hence, they can be considered harmless.

Do Picture-Winged Flies Bite
Picture Winged Fly

Are Picture Winged Flies Harmful in Any Other Way?

Again, while they’re not flies that will particularly attack or bite, they can sometimes cause a nuisance if they appear in swarms around your home.

Generally, adult picture-winged flies can be seen out and about during fall. Because of the drop in outside temperatures, they search for warmer surroundings and may try to sneak indoors looking for the same.

If you see picture-winged flies in large numbers gathering on the structure of your house, it’s best to secure every tiny little space that they can sneak in through.

They won’t damage any outdoor furniture in case you have any, and their numbers will naturally gradually decline as the temperature gets colder further.

What They Eat and Why They Are Beneficial?

Most adult picture-winged flies are often seen around decaying organic materials, such as compost pits and places with rotting vegetation.

This is because adult flies often lay eggs inside rotting fruits or vegetables that may either be on the ground or half buried beneath the soil surface. Their larvae feed on the rotting matter once they hatch.

As a result, adult flies are often seen around garbage dumps and swamps, moist areas which are not in use, and sometimes woodlands.

The Delphinia picta usually does not feed on fresh fruit or vegetables. However, some species of picture-winged flies are known to feed on live plant tissue.

Picture-winged flies are among those creatures in our ecosystem that feed on decomposing material and break it down, thereby lending a hand in cleaning up the environment.

Do Picture-Winged Flies Bite

What Are Picture Winged Flies Attracted To?

Since picture-winged flies are known to feed on rotting and decaying plant matter, it can be said that they are attracted to compost pits, and garbage dumps with rotting fruits and vegetables. They can also be attracted by color.

So you can spot picture-winged flies in and around newly painted outdoor spaces. Similarly, if there’s a compost pit in your yard, you can expect to see picture-winged flies in and around the outdoors.

Frequently Asked Questions

What is a fly with spotted wings?

The most common pest with spotted wings is the fruit fly.
While most fruit flies attack overripe or rotting fruits, there are one particular species known as the Spotted Wing Drosophila that attacks fresh fruit and can turn into a notorious pest.

What are the flies with stripes?

Flies with stripes or bands on their pair of wings can be picture-winged flies.
They are known to have striking patterns in black, brown, or yellow on their wings. They are considered to be among the most attractive species of flies.

How do you get rid of picture-winged flies?

The population of picture-winged flies naturally declines with the drop in temperatures and colder climates.
Until then, it’s advisable to secure all nooks and crannies of your home. This will keep your home safe from infestation by large swarms of these flies.

Why do I have striped flies in my house?

Picture winged flies are flies with banded stripes on their wings. They often mature during late summer and then search for warmer environments once the temperatures outside start cooling after fall.
This may be the reason why they sneak inside houses to find warmer surroundings.

Wrap Up

Picture-winged flies are among the most attractive creatures among the family of flies, owing to the striking patterns on their wings.

Generally harmless, these flies can surely cause a nuisance when they congregate in numbers.

If you’re noticing a swarm of adult picture-winged flies around your home, the first thing to do is to secure all entries to the house.

Do not forget to pack all corners and gaps to avoid infestation indoors. Thank you for reading this article.

Reader Emails

Over the years, picture-winged flies have caught the fancy of many of our readers. They have often been scared and sometimes enamored with these bugs as they fly around compost pits or make their homes inside our houses. 

We share below a selection of such emails, and you be the judge of how terrifying or fascinating these flies are!

Letter 1 – Picture Winged Fly reported to have bitten child

Subject: This type of bug bit my 1yr old
Location: NJ
July 20, 2015 4:17 pm
I am trying to find out what type of bug this is. It bit my 1yr old on the side of his head and he swelled up instantly and pretty severly. We took him to the doctor and they put him on antibiotics as a precaution.
Signature: Jeremy Lynch

PIcture Winged Fly
PIcture Winged Fly

Dear Jeremy,
We are surprised to learn that you suspect this Picture Winged Fly,
Delphinia picta, of biting your child.  Are you certain this is the culprit?  If you are correct, this is the first we have ever heard of a person being bitten by a Picture Winged Fly, though Eric Eaton once informed us that “if it has a mouth, it can bite.”  You can get additional information on the Picture Winged Fly at BugGuide.

Letter 2 – Picture Winged Fly

Fruit fly but what species?
“Picture wing”?
Help, Please.
Cheri Miller

Hi Cheri,
We wanted Eric Eaton’s opinion before writing back to you. Here is his response: ” No, don’t recognize the genus or species, but am fairly certain it is a picture-winged fly in the family Ulidiidae (formerly Otitidae), or something very closely related. The host plant should help you narrow it down further, in your copious spare time. Eric “

Letter 3 – Picture Winged Fly

Subject: Flying bug
Location: Fayetteville, NC
June 22, 2013 4:50 pm
Can you tell what this bug is?
I found three of this crawling
along the outside wood frame of my picture window.
It’s body looks like the size of a carpenter ant, or deer fly. I can not find pictures of any with wings that look like this.
Signature: SRE

Picture Winged Fly
Picture Winged Fly

Dear SRE,
You have encountered a Picture Winged Fly,
Delphinia picta.  According to BugGuide:  “Wing pattern apparently distinctive, with two white triangles on front edge. Moves wings in rowing motion as it walks.”

Letter 4 – Picture Winged Fly

Subject: Unknown bug sparked my curiousity
Location: Flushing,Queens,New York
September 17, 2013 5:32 am
Hello there!
I was photographing on a beautiful sunny day at the Queens Botanical Garden in NY, when suddenly this guy came into my view. I was photographing the bees pollinating when my curiosity was sparked. I have never seen wings like these before. It was like this little insect had personality. I came into the frame, walked up to the lens, looked right at it and turned around an walked away.
Can you shed some light on what this is?
Signature: Natali S. Bravo

Picture Winged Fly
Picture Winged Fly

Hi Natali,
Your Picture Winged Fly,
Delphinia picta, is well documented on BugGuide.

Letter 5 – Picture Winged Fly

Subject: Picture winged fly?
Location: Galesburg, Illinois
June 24, 2014 5:24 pm
Found this little fly preening itself in the car, next to an open window. Guessing it’s, maybe, a picture winged fly? Thank you very much.
Signature: Susurra Fonseca

Picture Winged Fly
Picture Winged Fly

Dear Susurra,
You are correct that this is a Picture Winged Fly, and as you can see by the matching image on BugGuide, it is
Delphinia picta.  Your image is quite stunning.

Letter 6 – Picture Winged Fly

Subject: Unusual flying bug
Location: Teaneck, nj
September 20, 2015 11:53 am
Please help me identify this creature. I have only recently noticed them hanging out in my yard
Signature: Mark

Picture Winged Fly
Picture Winged Fly

Dear Mark,
Your Picture Winged Fly is Delphinia picta, which you can verify by comparing your individual to this image on BugGuide.  According to BugGuide, it:  “Breeds in decaying organic matter, such as compost” so if you have a compost pile, that might explain their sudden appearance.

Letter 7 – Picture Winged Fly

Subject: SW PA flying bug
Location: SW Pennsylvania
May 21, 2017 7:11 am
I have searched for an answer, but alas, have come up empty handed…thus landing on your website for a possible answer.
This insect is plentiful in my yard outside of Pittsburgh. When it lands, it gently open and closes it’s wings. It doesnt appear to be aggressive, but Im wondering if it harms plants? Or does it fees off other insects?
Signature: Thanks for your time!

Picture Winged Fly

This is a Picture Winged Fly, Delphinia picta, and according to BugGuide:  “Breeds in decaying organic matter, such as compost” so we are suspecting you have a compost pile.

Wow, thank you!  Still a bit odd because we have no compost pile!  But we are surrounded by woods, so I guess there’s always things rotting somewhere.
Thanks again!!!

Letter 8 – Picture Winged Fly

Subject: I really want to know what big this is.
Location: Kalamazoo, Michigan, USA
June 2, 2017 6:24 pm
I saw this bug on my apartment building and it scared me.
Signature: Krystina Edwards

PIcture Winged Fly

Dear Krystina,
You have nothing to fear.  This is a Picture Winged Fly,
Idana marginata, and we verified its identification on BugGuide.  What appears to be a stinger is actually the ovipositor of a female, an organ she uses to lay eggs.  According to BugGuide, the larva “Develops in compost” and adults are “Sometimes found feeding on sap at tree wounds.”  An amusing encounter with this insect is published on The Incorrigible Entomologist:  “Walking around my yard one morning a few years ago, I looked up into a maple tree to see an unbelievably beautiful insect. Golden yellow and tan, with a striking pattern of black stripes and splotches, the critter looked down at me, rowing its wings back and forth with a feeling of knowing exactly what it was doing. It was unmistakably a fly, but it was huge by Maine fly standards – about 10 mm long. It was also perched high up on the tree trunk, too high to be reached by hand or net. Luckily I had my camera with me. Unluckily, it was only my little point and shoot. I took aim and fired off three shots before the fly, well, flew. Only one photo was in focus, and since the critter was so far away, it was not a very good photo at all. Something as distinctive as this had to be identifiable, though.  ‘Well’, I thought, ‘I’ll post it on BugGuide and see if anyone can point me in the right direction’. Two hours later I had my answer, courtesy of veteran BG editor v belov. It was Idana marginata, eastern North America’s largest picture-winged fly. This family, Ulidiidae, contains about 130 species in North America, many of which are very brightly colored and patterned, hence the common name. Most develop in decaying organic matter, or in roots.”


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. 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.

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  • 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.

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10 Comments. Leave new

  • Curious Girl
    July 21, 2014 5:54 am

    This is a girl fly though, isn’t she?

    Her Bad A** is an ovipositor I believe… am I wrong here?

  • Thank you!!! I’ve been seeing these all over recently, the females with stingers scared me.

  • I am pretty sure that this is actually a Pyrgotid fly,

  • I was stung by a picture winged fly , I was in a walk , coming out of woods , the sting was very painful. It stung through my sock on my ankle bone. It became swollen, I had to soak my ankle in epson salts. 4 days later, it is still red and itchy .

  • I just killed one in my house and there was blood coming out of it on the paper towel I smashed it with so I’m having a hard time believing that they don’t bite. It would be nice if someone could confirm from the picture I took of it. If it’s something else that could be dangerous to my family I’d like to make sure we don’t get any more but those wings look really unique.

  • While mowing I had several keep biting my hand. I felt a slight pain and there it was so I swatted it away then a min later felt the pain again and there it was again. This happened several times. It was definitely a insect that looked similar to this. Black and white wings, black body. Wings in a triangular shaped position like.
    Now my hand is itching. Perhaps more research needs to be done on these.

  • While mowing I had several keep biting my hand. I felt a slight pain and there it was so I swatted it away then a min later felt the pain again and there it was again. This happened several times. It was definitely a insect that looked similar to this. Black and white wings, black body. Wings in a triangular shaped position like.
    Now my hand is itching. Perhaps more research needs to be done on these.

  • Omg I was just bite by one ans it hurts


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