Feather Legged Fly 101: Essential Facts and Tips

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Feather-legged flies are fascinating insects that are often mistaken for bees due to their bee-like appearance. They have a distinctive fringe of hairs on their hind legs, which mimic a bee’s “pollen basket.” In North America, there are six species of these true flies, which can be identified by their yellow coloration and hairy hind legs source.

These tiny creatures play a beneficial role in controlling garden pests such as squash bugs and stink bugs. Female feather-legged flies deposit their eggs on these host insects, where the eggs hatch and their larvae feed on the bugs. While these flies can be seen as garden “friends,” it’s important to remember that they rely on these pests to survive and reproduce source.

Feather Legged Fly: Basic Identification

Family and Order

Feather-legged flies belong to the family Tachinidae and the order Diptera. They are closely related to the genus Trichopoda, which is known for their distinctive hairy or feathery hind legs.

Size and Appearance

Feather-legged flies display a unique combination of colors and features, making them relatively easy to identify. Key characteristics of these flies include:

  • Yellow coloration
  • Black wings
  • Orange or all-orange abdomens
  • Dark or dark-tipped abdomens

Their modified second pair of wings, called halteres, also play a significant role in their identification.

Size Comparison:

Feature Size
Body Length 8-12 millimeters

Distribution

Feather-legged flies are widely distributed across North America, with six species found in Mexico. In general, the geographic range of these flies includes:

  • North America
  • Mexico

These insects can be found in various habitats, ranging from gardens to forests, wherever their preferred host insects are available.

Feather Legged Fly: Life Cycle

Eggs

Feather legged flies are beelike insects that lay their eggs on host insects like squash bugs, stink bugs, and other true bugs1. Their eggs are strategically deposited on or near host insects to expedite the life cycle process. Female flies can lay multiple eggs.

Larvae and Nymphs

The life cycle of feather legged flies progresses as follows:

  • Larvae hatch from eggs.
  • They immediately seek host insects to parasitize1.
  • Larvae burrow into the host insect and feed internally1.
  • The host insect eventually dies due to larval feeding.

Feather legged fly larvae are often seen feeding on:

  • Squash bugs
  • Stink bugs
  • Leaf-footed bugs

Pupation

After completing the larval stage, the larvae exit the host insect and begin to pupate. Pupation usually occurs near host insects or flowers where adult flies are likely to be found.

Adult Flies

Adult feather legged flies are characterized by:

  • A bee-like appearance
  • A feathery fringe of hairs on their hind legs1
  • Yellow coloration with black markings2

Adult flies feed on nectar from flowers and perform important pollination. At this stage, they seek mates to restart the life cycle2.

Feather Legged Fly: Beneficial Aspects

Predatory Nature

Feather-legged flies (Trichopoda pennipes) are part of the tachinid fly family and are known for their bee-like appearance and feathery hairs on their hind legs source. These flies have a predatory nature as their larvae are parasitoids of other insects, specifically targeting plant bugs like squash bugs, stink bugs, and leaf-footed bugs, which are considered pests in many gardens and crop fields source.

Feather-legged flies find their prey while they’re cruising for nectar on flowers. They lay their eggs on the identified prey, and soon after the maggot hatches, it tunnels inside the host, feeding on its innards for nearly two weeks source.

Biological Pest Control

Feather-legged flies are considered beneficial insects in pest management and have the potential to serve as a non-toxic biological control agent for common pests in gardens and crop fields. For example, they’ve been used to control squash bugs, a major pest in gardens and crop fields source.

Their ability to parasitize a range of pests without causing harm to non-target organisms makes them an attractive option for integrated pest management (IPM) systems. Here are some pros and cons of using feather-legged flies as a biological control:

Pros:

  • Effective against a variety of pests
  • Non-toxic and environmental-friendly
  • Do not harm non-target species
  • Can be used as part of an integrated pest management strategy

Cons:

  • May require monitoring and management
  • Might not be as effective as chemical control in certain situations
  • May be sensitive to extreme weather conditions

In conclusion, the beneficial aspects of feather-legged flies make them an important part of pest management strategies.

Feather Legged Fly: Human and Ecosystem Connections

Impact on Crop Pests

Feather-legged flies, known scientifically as Trichopoda pennipes, play a crucial role in controlling crop pests. These flies lay their eggs on host insects, such as squash bugs, stink bugs, and other true bugs. By doing this, they help to naturally reduce the populations of these pests. For example, their larvae are known to target shield-backed bugs that can damage various crops.

Farmers and gardeners in areas like Missouri appreciate feather-legged flies as a non-toxic form of pest control. Here are some impacts on crop pests:

  • Reduces the need for chemical pesticides
  • Limits the damage caused by invasive pests
  • Contributes to a more sustainable agricultural ecosystem

Importance in Pollination

Besides their role in controlling pests, feather-legged flies also serve as important pollinators. As they feed on nectar, they aid in the pollination of plants, making them crucial in maintaining healthy ecosystems. Feather-legged flies mimic bees, including their pollen baskets, which are essentially a fringe of hairs on their hind legs.

Examples of their importance can be seen in the relationship they have with plants during spring and summer seasons, as they:

  • Help plants reproduce by transferring pollen from one flower to another
  • Provide essential ecosystem services that support food production

Overall, feather-legged flies provide essential connections between various invertebrates, humans, and ecosystems. They influence the health of our environment and the crops we grow by acting as both natural pest control and pollinators.

Feather Legged Fly: Related Species and Families

True Bugs and Their Families

True bugs belong to the Hemiptera order and include various families like Coreidae, Largidae, and Scutelleridae. Examples of true bugs are leaf-footed bugs and Nezara viridula.

Some key features of true bugs are:

  • Piercing and sucking mouthparts
  • Front wings are half membranous and half leathery
  • Triangular plate (scutellum) between wings

Leaf-footed bugs are mostly found in the Coreidae family, often feeding on plant sap. Bordered plant bugs, seen in the Largidae family, prefer feeding on the juices of other insects.

Other Tachinidae Species

Feather-legged flies are part of the Tachinidae family, one of the largest and most diverse groups of flies. It contains over 10,000 species and is still growing.

These flies are parasitic on various insects like true bugs, including leaf-footed bugs and stink bugs. In North America, specifically north of Mexico, there are six species in the genus of true flies.

Here is a comparison table displaying key differences between true bugs and Feather Legged Flies:

Characteristics True Bugs Feather Legged Flies
Family Coreidae, Largidae, etc. Tachinidae
Feeding Plant sap or insect juices Parasitic on various insects
Wings Half membranous/leathery Similar to bee wings

In conclusion, Feather Legged Fly’s related species and families mainly cover the true bugs from various families, and their parasitic relationship connects them to numerous insect species in the diverse Tachinidae family.

Footnotes

  1. Feather-Legged Flies Hairy-Legged Flies 2 3 4

  2. Feather-Legged Flies 2

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 – Feather Legged Fly

 

Feather Legged Fly Images ,Date ,Time ,Location
Fri, Oct 10, 2008 at 9:03 AM
Hi Bugman
I spotted this neat looking bug on a hibiscus in my backyard on July 14 ,2008 at 10:31a.m.
It was just buzzing around and landing on the leafs – not on the orange and yellow flowers. This is the first time I ever saw this kind of bug and have not seen one since. I thought it might
be a wierd species of wasp because of the abdomen. It has a really beautiful color of orange and these wierd looking combs on it’s legs.
Thank’s Once Again! & Have a Great Day!
Brent Hansen
Pinellas County ,Florida

Feather Legged Fly
Feather Legged Fly

Hi Brent,
Thanks so much for allowing us to post your image of a Feather Footed Fly, Trichopoda pennipes. The solid orange abdomen indicates that this is a male Feather Footed Fly. Feather Legged Flies are Tachinid Flies in the family Tachinidae. Here is what BugGuide has to say about this species: “Adult female lays one to several eggs on a hemipteran host. The larvae hatch from the eggs and burrow directly into the bug’s body, though only one larva will survive within each host. The larva feeds on the host internally and eventually a large cream-colored maggot exits from body of the bug (which soon dies). The maggot pupates in a dark reddish-brown puparium in the soil and emerges as an adult about two weeks later. There are up to three generations a year depending on location, and larvae may overwinter in the bodies of overwintering hosts. “We will try to assist you in the identification of other unidentified insects on your website when we have an opportunity. Right now, we are trying to subcategorize our own archives and it is quite a daunting task. Since our site migration, we are trying to learn all the nuances for posting information that are now available to us. It has taken us weeks (we haven’t much spare time) to partially subcategorize 36 pages of our 81 pages of beetle postings. We now realize the subcategorization needs to be more extensive and will need to start at the beginning again, but not until we finish the current task. After that, we plan to further subcategorize True Bugs, Butterflies, Caterpillars and Spiders. The problem is that this “busy work” interferes with our precious posting time of new submissions.

Letter 2 – Feather Legged Fly

 

some pics for you
These are a random sampling of pictures I took while walking in my favorite park. I hope you like them.  Arlington, Texas
Elizabeth

Feather Legged Fly
Feather Legged Fly

Hi Elizabeth,
We are especially eager to post your image of a Feather Legged Fly, Trichopoda pennipes.  According to BugGuide:  “Adult female lays one to several eggs on a hemipteran host.  The larvae hatch from the eggs and burrow directly into the bug’s body, though only one larva will survive within each host.  The larva feeds on the host internally and eventually a large cream-colored maggot exits from body of the bug (which soon dies).  The maggot pupates in a dark reddish-brown puparium in the soil and emerges as an adult about two weeks later.  There are up to three generations a year depending on location, and larvae may overwinter in the bodies of overwintering hosts. “

Letter 3 – Feather Legged Fly

 

Wasp Moth?
Hello Bugman:
I live in the Williamsport, Pennsylvania area. Here are some photos of a bug I have taken in the past few days. He is seen feeding on the goldenrod amongst many other bees and wasps. It is a little over an inch long. I can’t tell if it is a bee, wasp, moth or some combination. Any help would be appreciated.
Thanks,
Alex

Hi Alex,
This beauty is a Feather Legged Fly, Trichopoda pennipes, one of the Tachinid Flies. According to BugGuide: “Adult female lays one to several eggs on a hemipteran host. The larvae hatch from the eggs and burrow directly into the bug’s body, though only one larva will survive within each host. The larva feeds on the host internally and eventually a large cream-colored maggot exits from body of the bug (which soon dies). The maggot pupates in a dark reddish-brown puparium in the soil and emerges as an adult about two weeks later. There are up to three generations a year depending on location, and larvae may overwinter in the bodies of overwintering hosts.” and “Often used as biological control of hemipteran pest species such as squash bugs, stink bugs, and plant bugs. May hover above squash plants in search of prey.” The black tipped abdomen is a signal that this is a female fly.

Letter 4 – Feather Legged Fly

 

Subject: Fly/Bee
Location: Eastern Massachusetts
June 29, 2012 6:32 pm
I found this insect on my butterfly bushes. Its wings were always stuck out to the side, never laying across its abdomen (like with most flies and bees). What is it?
Signature: Denny P

Feather Legged Fly

Hi Denny,
This colorfly fly is a Feather Legged Fly in the genus
Trichopoda and you may read more about this fascinating genus on BugGuide.  We believe this may be Trichopoda pennipes based on these BugGuide photos.  Feather Legged Flies are in the Tachinid Fly family and they are important beneficial insects since the larvae are parasitic on Stink Bugs and other Heteropterans that feed on plants.

Letter 5 – Feather Legged Fly

 

Subject: Stumped by a fly
Location: andover township, nj
July 1, 2015 5:17 am
Hi Daniel,
I found this very interesting fly in my garden yesterday and I have been completely unsuccessful in finding an ID for it. Hoping you can help. One thing that was interesting was that it had a thick line of “feathering” on its hind leg. I’ve cropped these photos so that you can see the detail.
Hope you can help!
Signature: Deborah

Feather Legged Fly
Feather Legged Fly

Hi Deborah,
Your Feather Legged Fly has some noticeable differences when compared to the images on BugGuide of
Trichopoda pennipes, but we are still relatively confident in that as the identification.  The BugGuide description is:  “Bright orange abdomen, velvety black head and thorax, and a fringe of short black hairs on the hind legs. Male: ferrugineous spot in the wing, abdomen dark orange at apex; female: wing evenly dusky, abdominal tip black.”  The biggest difference is the black abdomen on your individual, which just may be an example of variation within the species.  Your side view clearly shows the feathered hind legs.  This Feather Legged Fly is an important biological control agent, and BugGuide lists the hosts as:  “various pentatomorph bugs (Coreidae, Largidae, Pentatomidae, Scutelleridae) …  Anasa tristis is an important common host.” 

Feather Legged Fly
Feather Legged Fly

Udate:  In looking through our own archives, this might be Trichopoda lanipes.

Thank you, Daniel!  That does look like my fly!  As always, I appreciate your assistance.
Debbi

Feather Legged Fly
Feather Legged Fly

Letter 6 – Feather Legged Fly

 

Subject:  Feather-legged Fly
Geographic location of the bug:  Andover, NJ
Date: 08/15/2018
Time: 12:57 PM EDT
Your letter to the bugman:  In addition to the colorful T. pennipes, I had this larger feather-legged fly in my mountain mint patch today.  My best guess is that it is T.  lanipes.  It was quite large and had the most beautiful wings. It’s under-belly was an orange-red color, which was kind of a surprise.   Did I land on the right id?
How you want your letter signed:  Deborah Bifulco

Feather-Legged Fly

Hi Deborah,
The last time you submitted images of a Feather Legged Fly, we originally thought it was
Trichopoda pennipes, but upon further contemplation, we believe it was Trichopoda lanipes.  We agree with you that this is also most likely Trichopoda lanipes.  We especially like that there is a Metallic Sweat Bee in the bottom of one of your images.

Feather-Legged Fly
Feather-Legged Fly and Metallic Sweat Bee

Letter 7 – Feather-Legged Fly from Portugal

 

Some kind of fly
Location:  Portugal
August 27, 2010 3:12 pm
Hi,
I found this fly on my bean plants the other day. No idea what it is. Can you help me identifying it?
Dania

Feather-Legged Fly

Hi Dania,
We started to try to identify your fly on BugGuide before we realized you were writing from Portugal.  Your insect is a close match to the Feather-Legged Fly
Trichopoda pennipes, and we suspect it is closely related.  Feather-Legged Flies are Tachinid Flies and according to BugGuide:  “Adults feed on nectar, larvae are internal parasites of true bugs.  Life Cycle:  Adult female lays one to several eggs on a hemipteran host. The larvae hatch from the eggs and burrow directly into the bug’s body, though only one larva will survive within each host. The larva feeds on the host internally and eventually a large cream-colored maggot exits from body of the bug (which soon dies). The maggot pupates in a dark reddish-brown puparium in the soil and emerges as an adult about two weeks later. There are up to three generations a year depending on location, and larvae may overwinter in the bodies of overwintering hosts. BugGuide also indicates:  “Often used as biological control of hemipteran pest species such as squash bugs, stink bugs, and plant bugs.  May hover above squash plants in search of prey.  According to Paul Beuk it has been ‘introduced into Europe and is now frequently spotted in the south. Its exotic appearance has dumbfounded many a European entomologist. That final statement implies that Feather-Legged Flies are not native to Europe, so this fly may be a North American species afterall.  Your beautiful images are a wonderful addition to our archives.

Feather-Legged Fly

Thanks, Daniel.
That’s very interesting. I was quite intrigued by it since I had never seen anything like that before. Now I’m curious as to how common they are around here, I will certainly be paying more attention from now on. Thanks again.

Letter 8 – Featherlegged Fly

 

Subject:  Black fly, yellow stripe on head
Geographic location of the bug:  Westfield, MA, USA
Date: 07/11/2020
Time: 01:47 PM EDT
Your letter to the bugman:  We have a hybrid hydrangea that blooms through July.  Some days there are many dozens of insects enjoying the blooms.  I cannot identify this one.
How you want your letter signed:  Steveb

Featherlegged Fly

Dear Steveb,
This is one of the parasitoid Tachinid Flies in the genus
Trichopoda which are known as the Featherlegged Flies, and it is probably Trichopoda lanipes which is pictured on BugGuide.  According to BugGuide, it preys on Leaf Footed Bugs in the family Coreidae.

Authors

  • 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
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