Braconid Wasp: All You Need to Know in a Nutshell

Braconid wasps are a fascinating group of insects that play a crucial role in maintaining ecological balance.

They belong to the family Braconidae, making them one of the largest families within the order of Hymenoptera.

These small, dark or dull-colored wasps are known for their parasitic behavior and diverse species, with over 19,000 species recognized worldwide.

One of the primary reasons gardeners appreciate the presence of braconid wasps is their ability to control pest populations.

They achieve this by laying their eggs inside the bodies of various host insects, particularly caterpillars.

As the wasp larvae grow, they consume the host from the inside, eventually killing it.

This helps to naturally reduce the number of pests that would otherwise damage plants and crops.

Though braconid wasps might not be overly attractive, their importance in the overall health of gardens and ecosystems is undeniable.

The knowledge of their life cycle and parasitic habits can help us understand and appreciate the role these tiny creatures play in our world.

What Are Braconid Wasps?

Family Braconidae

Braconid wasps belong to the family Braconidae, which is one of the largest and most diverse families within the insect order Hymenoptera.

There are over 19,000 known species of Braconid wasps, all of which have unique characteristics and habits.

• Small body size, ranging from a fleck of pepper to under 1/2″ long²
• Long, thin antennae and legs
• Wasp-like appearance
• Typically feed on pests during their larval stage

The well-known Cotesia spp. wasps (Braconids) are widely recognized for their rice-like pupal cocoons often found on tomato hornworms and cabbageworms³.

Order Hymenoptera

The order Hymenoptera includes the family Braconidae as well as other families of parasitoid wasps, such as Ichneumonidae.

Here’s how the Braconids compare to Ichneumonids:

Feature	Braconid Wasps (Braconidae)	Ichneumonid Wasps (Ichneumonidae)
Targeted Hosts	Caterpillars, various pests2	Mostly caterpillars4
Wing Vein Pattern	Unique to their family4	Different from Braconids4
Similar Characteristics	Long antennae, thin legs, wasp-like bodies	Same as Braconids4

These wasps are important for natural pest control, as they reduce pest populations by laying their eggs in or on them.

Once hatched, the larvae feed on their host, oftentimes leading to their death.

Braconid Wasp Morphology and Classification

Appearance and Coloration

Braconid wasps are typically small, slender parasitoid insects with thread-like antennae that have 16 or more segments¹.

Their coloration usually ranges from brown to black with a reddish abdomen¹.

Subfamilies and Synonyms

Braconid wasps belong to the family Braconidae, which is divided into several subfamilies, such as:

• Microgastrinae
• Ichneutinae
• Dirrhopinae
• Exothecinae
• Hormiinae
• Masoninae
• Meteorideinae
• Microtypinae
• Rhysipolinae
• Rhyssalinae²

The classification of these subfamilies has been extensively studied by researchers like Achterberg, Marsh, and Borror and DeLong².

Details about the morphology, larval hosts, and other characteristics of each subfamily can be found in the Systematics, Phylogeny, and Evolution of Braconid Wasps publication.

As mentioned earlier, Braconid wasps help control pest populations such as beetle larvae, soft-bodied caterpillars, and other insects from the orders Coleoptera, Diptera, and Lepidoptera³.

Life Cycle of Braconid Wasps

Eggs and Larvae

Braconid wasps have a fascinating life cycle, starting with the female wasp laying eggs inside or on the surface of their host insects.

Some examples of hosts include caterpillars and aphids.

Once the eggs hatch, the tiny larvae begin feeding on their hosts’ internal tissues, slowly consuming them from the inside.

The larvae grow rapidly as they feed on their hosts, eventually causing the host’s death.

At this stage, they undergo a metamorphosis and prepare for the next stage of their life cycle.

Pupae and Cocoons

As the larvae complete their development, they spin silken cocoons around themselves, usually on or near the host’s body.

Within these protective cocoons, they transition into the pupal stage.

This stage is a period of rest, during which the wasp undergoes significant transformations as it prepares to emerge as an adult.

Adult

Once the transformation is complete, adult braconid wasps emerge from their cocoons.

These adults typically have a short lifespan, during which their primary goal is to mate and lay eggs in new host insects.

They usually feed on nectar, pollen, and honeydew, which provides them with enough energy to complete their life cycle.

Characteristic	Adult Braconid Wasp
Size	Varies, often between a fleck of pepper and 1/2″ long
Diet	Nectar, pollen, honeydew
Lifespan	Short, varies among species
Reproduction	Lay eggs in or on host insects

In summary, the life cycle of braconid wasps consists of distinct stages, including eggs and larvae, pupae and cocoons, and adults.

Braconid Wasps in Agriculture

Beneficial Insects

Braconid wasps are beneficial insects because they act as parasitoids, targeting pests in various environments.

These wasps are proficient in biological control, as they use other organisms to suppress pests, such as the tomato hornworm.

Specifically, the Cotesia spp. wasps form clusters of yellowish pupal cocoons on tomato hornworms, killing the pests and preventing crop damage

Pros:

• Reduced need for harmful chemical pesticides
• Targeted control of specific pests
• Can reduce pest populations in agriculture, horticulture, and urban areas

Cons:

• May struggle to control larger pest populations
• Dependent on environmental conditions (habitat, temperature)

Comparison between Braconid wasps and chemical aphid control:

Method	Pros	Cons
Braconid wasps	Natural, efficient, environmentally safe	May not eliminate all aphids, need certain aphid population, slow process
Chemical	Fast-acting, efficient in eliminating aphids	Harmful to the environment, may affect other beneficial insects

Urban Areas

Braconid wasps can also be beneficial in urban areas, targeting pests found in gardens, parks, and other green spaces.

Are Braconid Wasps Dangerous?

Braconid wasps are not considered dangerous to humans.

They are parasitoid wasps, meaning their primary focus is on laying their eggs inside or on the body of specific host insects, such as caterpillars or aphids.

As the wasp larvae grow, they consume the host from the inside, eventually killing it.

This behavior makes them beneficial for natural pest control in gardens and agricultural settings.

Braconid wasps are generally not aggressive towards humans.

While some wasps in the order Hymenoptera (which includes bees, wasps, and ants) can sting, braconid wasps have a modified ovipositor (egg-laying structure) that they use for parasitizing hosts, and they do not use it to sting in defense.

Even if they were to try, their small size and delicate structure would make it unlikely for them to penetrate human skin.

Conclusion

Braconid wasps, belonging to the extensive Braconidae family, are vital players in ecological balance, especially in pest control.

Found globally, these parasitoid wasps lay their eggs in host insects, aiding in natural pest management.

While they might not be the most visually appealing insects, their role in preserving garden health and overall ecological balance is undeniable.

Recognizing their life cycle, parasitic habits, and benefits can foster an appreciation for these tiny ecological warriors.

Footnotes

1. https://blogs.ifas.ufl.edu/stjohnsco/2021/09/19/ipm-biological-control-the-braconid-wasp-cotesia-congreta/ ↩ ↩² ↩³
2. https://extension.umd.edu/resource/parasitoid-wasps ↩ ↩² ↩³ ↩⁴
3. https://extension.umd.edu/resource/braconid-and-ichneumonoid-wasps ↩ ↩²
4. https://entomology.ces.ncsu.edu/biological-control-information-center/beneficial-parasitoids/cotesia-wasp/ ↩ ↩² ↩³ ↩⁴ ↩⁵

Reader Emails

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

Letter 1 – Possibly Braconid accused of Biting

Subject: Unknown insect
Location: Northern Atlantic
July 18, 2013 7:26 pm
This bug bit my girlfriend #3 times . she was walking her jack russell , behind the storage shed. She was bittin on the stomach. North Atlantic Region 7/17/ 2013 Pa.17961 .
Signature: Waiting patiently

Dear Waiting patiently,
This appears to be a Parasitoid Hymenopteran, a member of the insect order that includes such stinging insects as Wasps and Bees.  According to BugGuide:  “A very large and important group. Wasplike in appearance, but (with rare exceptions) do not sting.”

Letter 2 – Parasitoid Wasp: Braconid species

Subject:  Red Bodied Winged Bug
Geographic location of the bug:  Clearwater Florida
Date: 09/27/2017
Time: 11:32 AM EDT
Hi Bugman Saw this bug in Clearwater Florida. It’s a really Cool! looking bug. If you have the time – Would you Please identify for me. Thank You Very Much! Brent
How you want your letter signed:  Brent Hansen

Dear Brent,
Your images are both gorgeous and perfect for attempting an identification:  dorsal and ventral views.  We must also confess that we identified your Braconid Wasp early this morning, but the time clock began ringing.  Your pretty female, as evidenced by her lengthy ovipositor, looks to us like this member of the genus Bracon that is pictured on BugGuide.

Hi Daniel Thank You Very Much!!! for the compliment and for your quick response and identification. Have a Great Day! Brent

Letter 3 – Possibly Braconid Wasp

Subject: Wood eating mystery!!
Location: Southeast idaho
August 5, 2016 4:40 pm
Hoping you can identify this bug for me. I live in southeast Idaho and the other day I noticed a VERY loud chewing sound coming from a pile of branches I have in my backyard. When I went over to look all I could see was sawdust looking stuff all over, but I couldn’t find any bugs anywhere.

Then today I noticed a few of these bugs flying around. I was nervous at first because it looked like a termite, but I’m not sure that’s what it is. It has a red body, black wings, and long straight black antennas. I’m really hoping it’s not a destructive wood eater.
Signature: Sarah

Dear Sarah,
While we are not able to give you an exact species identification, at least we can alleviate your anxiety by informing you that this is NOT a Termite.  We are quite certain that it is a Parasitoid Wasp, and after scouring the pages of BugGuide for the past two days, we believe it is a Braconid Wasp in the family Braconidae. 

Our best guess at this time is that it might be in the genus Atanycolus, which according to BugGuide is “Next to impossible to identify this genus from images alone, however it is one of the more common genera in the subfamily” and they are found in:  “Woodland habitats for the most part.” 

BugGuide continues with this information:  “Parasites of woodboring beetle larvae, especially metallic wood-boring beetles (Buprestidae) and longhorn beetles (Cerambycidae)”  Here is a somewhat similar looking individual from BugGuide. 

Now, here is our theory, though you did not say much about the pile of branches, we suspect the wood may have been infested with the larvae of wood boring beetles.  The beetles do make loud noises when they emerge from the pupa and chew their way to the surface.  The appearance of these Braconids is an indication that nature is trying to balance things out. 

When hosts are plentiful, predators (or in this case Parasitoids) increase in number.  The female Braconid Wasp will lay her eggs, using her ovipositor, on or near the host, meaning the wood boring beetle larvae.  When the Braconid larvae hatch, they feed on the host, eventually killing it. 

Adult Braconid Wasps eventually emerge from the wood and mate to produce a new generation.  So, while this Braconid Wasp is not feeding on the wood, it is trying to control some wood eating species of beetle.  That means something is eating your wood pile.  Finally, since the individual in your image does not appear to have an ovipositor, we suspect it is a male.

Wow, you guys are awesome!! You really know your stuff! After breaking apart some of the branches, I did find some beetles and larvae. You nailed it! And now I’ll just leave the wasps to feast away! Thanks again!

Thanks for the confirmation.

Letter 4 – PLAGIARISM: Eucharitid Wasp

Ed. Note:  We don’t often have instances of plagiarism, but we believe we have been duped by Idk (email address name Clio Baumgardner) with this image which does not appear to have been shot by Idk, despite the claims in the body of the submission. 

We overlooked the copyright information on the image which does not match either the Idk signature or the Clio Baumgardner return email address.  Once we began to suspect, after Eucharitid expert John Heraty wrote “it certainly didn’t come from California (Old World only),” we located the image on the Myrmecos Blog Best Insect Photos of 2009 and credited to Rundstedt B. Rovillos. 

We also found it on FlickR where it is also credited to Rundstedt B. Rovillos.  Plainly and simply, stealing images from the internet is dishonest and it is plagiarism.  Idk is a thief.

Subject: Weird Bug
Location: California
January 10, 2016 2:41 pm
I found the super weird bug hanging in my favorite picnic spot, I’m wondering what it is! Luckily I got a clear shot of the bug. ???
Signature: Idk

Dear Idk,
This really is an unusual looking insect, and our gut instincts said “Parasitic Hymenopteran” however we could not find any matching images on BugGuide.  The feathered antennae are quite unusual for Hymenopterans, which include Ants, Bees and Wasps, so we did a web search of “wasp feathered antennae” and we discovered this image on FlickR that is identified as a Eucharitid Wasp from the Philippines with this information: 

“Eucharitid wasps are specialized parasitoids of ants. Larvae develop inside ant nests feeding on ant brood. Adult wasps sometimes form large mating swarms in meadows, where the females oviposit in plant material. Young larvae attach themselves to passing ants, or to ant prey items, to be carried into the ant nest.” 

There is another image with no information on Pinoy PHotography.  We couldn’t find any images on BugGuide with that distinctive thoracic spine, though we did find a species on BugGuide, Pseudochalcura gibbosa, that has feathered antenna. 

We found a similar image on the UC Riverside site, but there is no species name.  PBase has an Ecuadorean individual called a Bison Wasp.  We would really like to be able to provide you with a species identification, so we are contacting Eric Eaton for his input. 

Could you also provide us with a city in California where this Eucharitid was sighted?  We hope they prey on invasive Argentine Ants.

Eric Eaton Responds
Hi, Daniel:
Happy New Year!
I found I already liked the Facebook page for WTB, and saw this posted there.  I have shared it with the “Hymenopterists Forum” group, which is filled with experts on all things ants, bees, and wasps.  Someone there should be able to offer help.  I’ll keep checking the results.
Eric

Identification by expert John Heraty:  Schizaspidia species
Daniel:
This, from John Heraty, a world authority on the family:
“This is Schizaspidia (Eucharitidae), but it certainly didn’t come from California (Old World only).”
Eric

We write back to Idk for clarification.
Hi again Idk,
Please clarify where in California this image was shot as it is not a California species.  It is also curious that the name on the file is Rundstedt B Rovillos, which is different from the Idk you signed and the Clio Baumgardner return address on the email.

We write to Rundstedt.
Dear Rundstedt,
This gorgeous image was just submitted to What’s That Bug? and after posting it and having it identified as a Schizaspidia species thanks to the opinion of Eucharitid expert John Heraty, we realized that the image was plagiarized from the internet.  We hope you will allow us to continue to keep the image on our site, correctly credited to you.
Daniel Marlos

Dear Daniel,
Thank you for bringing this matter to my attention. I am the owner of this image.This tiny wasp was photographed at La Mesa Ecopark located in Fairview, Quezon City Philippines several years ago.
Yes, you may keep this image on your site to inform others about this beautiful creature.
Cheers!
Rundstedt Rovillos

Letter 5 – Holy cow this is a big bug…

It has been raining for days and the leaves toward the bottom of my tomato plants are starting to look yellow. Then I saw what I thought were tiny little white bugs and figured I could just pluck them off. Much to my surprise they were part of, or attached to, a very large slug like creature that had suction cupped itself to the plant.

What the heck is it, or are they? What can I do to get rid of it? I also found a smaller orange like slug that I smushed. Again, what is it and what do I do about it? And then, because things come in threes, I found droppings, on the leaves, that were the size of a small childs fingernail bed. hard to tell if it is bird poop or otherwise.

This is the first time I am growing vegetables and these plants were hand cultivated by good friends. I want to make sure I do the right thing…too embarrassing to let their hard work, and mine, go to the bugs.
Please help.
Many thanks!
Risa Hochroth

Dear Risa,
I wish you had sent a photo. The tiny white bugs you found were doing your job for you. It is perfect bio-warfare. They are the pupae of a type of parasitic Braconid wasp. The female wasp lays her eggs inside (using an ovipositor) the larva of a tomato hornworm, a common pest on tomatoes.

It is the green sluglike creature you found. The larvae of the wasp eat the hornworm inside out, then pupate on the outside, the stage you discovered. The caterpillar then dies and the wasps mature and begin a new cycle. The Tomato Hornworm >is the caterpillar of a large moth, Manduca sexta or Manduca quinquemaculata.

The larvae are identified by the horn at the posterior end and they attain a length of four or more inches and a girth equal to a human finger before burying into the ground to pupate. While in the caterpillar form, they can defoliate entire branches of a tomato plant as well as nibbling on the still green tomatoes.

Thank you.
So, if I have handpicked the two I saw, what should I do to prevent others from appearing and destroying the plant. I assume if there were 2 there are more, yes? I sprayed insecticidal soap on the foliage, but I am wondering if there is more I should do other than just keep looking for them and handpicking them off.

On the web I read that I should not have killed the hornworm with the wasps, which is consistent with what you have said, but should I have left it there to have the wasps potentially kill other worms. I thought leaving them would just give them more time to eat the foliage and the tomatoes that they have already munched on.

Also, once I harvest the last tomatoes, isthere anything I need to do to the soil to make sure that they are not going to be there next year?
Risa Hochroth

Hand picking is, in our opinion, the best means of control. Watch for the telltale signs, nibbled leaves and droppings, then search for the grazer. You can sift through the soil to locate the large pupae, but adults can just fly in and lay eggs.

A dilligent eye is the best form of control since we do not endorse undue use of pesticides in the garden, especially on produce meant for human consumption.