In this article, we will share a collection of blue mud wasp facts, such as where they come from, what they eat, and how they are able to kill spiders much larger than themselves.
Are you scared of spiders? Particularly the poisonous black widow spiders?
If yes, then the blue mud wasps are your savior. They are one of the 30-plus species of mud dauber wasps and are known to hunt and eat black widow spiders regularly.
But since they hunt such dangerous spiders, they, too, are dangerous to humans, right? Wrong!
Let us know about them in detail.
What Are Blue Mud Wasp?
Blue Mud wasps are the sworn enemies of black widow spiders.
These wasps are experts in hunting down and consuming black widow spiders, which are extremely dangerous and poisonous to humans.
Blue mud wasps are also known as Chalybion Californicum and Blue mud dauber.
They are solitary in nature and are not found in wasp colonies. The female wasps individually build and supply food to their nests.
They belong to the Sphecidae family.
These magnificent insects are found throughout northern Mexico to Southern Canada. You can also spot them in other regions of Bermuda and Hawaii.
But how can you identify these species of mud dauber wasps?
Let us find out in the next section.
What Do Blue Mud Wasps Look Like?
As the name suggests, the blue mud wasps can be identified by their blue and black colored bodies.
They have a tiny thread-like waist(like a narrow cylindrical tube) and show an average growth of 0.47- 0.7 inches in length.
Adult wasps can fly and have blueish wings. The larvae are legless with creamy white bodies and are mostly around an inch long.
If you look closely, you will notice a stinger that the adults use to paralyze and hunt down spiders.
As they are good pollinators, you can find them flying around common wildflowers, searching for nectar.
What Does A Blue Mud Wasp Eat?
Blue mud wasps are carnivorous when in their larval stage, but after they reach adulthood, they mostly rely on nectar to fulfill their diets.
The adults are experts in hunting down spiders by stinging and paralyzing them, which then become food to the larvae (we will explain this in-depth later).
Adult wasps mostly rely on nectar to fulfill their food needs.
You can find them around common wildflowers like Zizia Aurea, Daucus Carota, and Berberis Vulgaris.
Where Do Blue Mud Wasps Live?
As mentioned above, blue mud wasps are found throughout northern Mexico to Southern Canada.
In the US, it is most common in the Michigan area, especially near the Great Lakes region.
Unlike the organ-pipe mud daubers, these wasps do not build their own nest; They often occupy the pre-existing nest of the black and yellow mud daubers.
On spotting black and yellow mud dauber nests, they remove the existing larvae and other unwanted species from the mud cells.
Once done, they replace the cells with their own eggs.
These nests are often found near shaded areas like the underside of bridges, abandoned machinery, and wooden piles.
Life Cycle of A Blue Mud Wasp
The life cycle of a blue mud wasp shares many similarities with other species of mud daubers, but there are a few unique aspects that we will discuss in this section.
After mating, the female blue mud wasps search for existing black and yellow mud dauber wasp nests.
Interestingly, the female blue mud wasp uses water to soften the existing nest. They empty the mud cells by eliminating the existing larvae and spiders.
Each mud chamber is filled with one egg and plenty of spiders to allow the larvae to grow into active adults.
Once the process is done, the sections are covered and closed with mud. The female departs soon after that.
The larva consumes all the existing spiders in the chamber before emerging.
Once the larva reaches around 0.75 inches, it starts pupating.
These larvae overwinter in the mud chambers and usually emerge during late spring or early summer.
You will be fascinated to know that the adult eats its way out of the mud chamber.
As adults, these wasps fly around wildflowers to drink nectar to fulfill their diets.
You can find them near spider-infested areas, hunting to feed the young ones.
How Long Do Blue Mud Wasps Live?
As adults, the various species of dirt dauber wasps do not live long. After emerging from the mud cell, an average mud dauber adult can live for 3 to 6 weeks.
Also, predators like birds hunt them down, cutting down their lifespan.
These insects live longer as larvae. In winter, these larvae enter diapause till spring.
Do They Bite?
Blue mud wasps have a stinger. They use it to paralyze prey like spiders. Yes, they can sting humans, but they usually do not attack.
However, you must be careful around them and not try to scare or manhandle these insects. The stings can be a little painful.
Are They Poisonous/Venomous?
Blue mud wasps are not poisonous to humans. However, as we mentioned above, adult mud daubers can sting.
Try not to scare the insect by touching them; they might use the stinger on you.
The stings can be temporarily painful and cause mild swelling. You can apply ice to lower the swelling and pain.
Are They Harmful or Beneficial to Humans?
Yes, blue mud wasps can sting humans, but they are rarely aggressive. They will sting if you try to threaten them. If you leave them be, there is no need to worry.
These wasps are beneficial to humans as they eliminate the poisonous black widow spiders.
Also, since they hugely rely on nectar to fulfill their diets, they are decent pollinators.
If you have an annoying population of spiders in your garden, these wasps can be the ideal tool to help you get rid of them.
Also, as they fall from one flower to the other, they will carry the pollen in their body. Thus, promoting cross-pollination.
What Are Blue Mud Wasps Attracted To?
Blue mud wasps are attracted to areas with abundant spiders, especially black widows.
Plus, the females look for shady spots to find mud nests of other dirt daubers to lay eggs.
As mentioned above, the adults are particularly attracted to wildflowers like Zizia Aurea, Daucus Carota, and Berberis Vulgaris.
Why & How Do Blue Mud Wasps Hunt Black Widows?
From the beginning, we are mentioning that blue mud wasps are excellent at hunting black widow spiders.
Have you wondered how they hunt such poisonous insects?
Let us find out.
Firstly, the blue mud wasps hunt these spiders to feed their young ones. Black widows are excellent sources of protein that help the larvae to grow.
They usually grab these poisonous spiders from the web and immobilize them using their stinger.
Once the spider is paralyzed, they carefully carry it to the nests of mud and put it in a mud chamber for the larvae to eat.
At times, these wasps lure the black widows to come out in the open to hunt them conveniently.
How To Get Rid of Blue Mud Wasps?
Blue and wasps usually do not pose any threat to humans. They are beneficial as they eliminate spiders and promote pollination.
However, having mud nests around the house can be a little too much to take.
You can carefully scrape off the nest of blue mud wasps to get rid of them.
Do not worry; the mother does not guard and defend the nest. In fact, they leave the mud nests after sealing the cells.
You can also use wasp and hornet aerosol sprays to treat the nest.
Look out for mud dauber nests in shady spots.
Interesting Facts About Blue Mud Wasps
The sections above pretty much carry all the information about blue mud wasps.
But there are a few more fascinating facts about these insects. Let us take a look.
- Blue mud dauber wasp larvae can consume many spiders. A mud dauber nest cell has around 25 paralyzed spiders.
- Potter wasps can be mistaken for mud daubers. You can differentiate between the two by observing the nest. Potter wasp nests are in the shape of a pot, and mud daubers have cylindrical nests.
- Significant populations of blue mud wasps have started blooming in regions of Hawaii and Bermuda.
- Blue mud wasps also lay a single egg in each mud cell of the nest.
Frequently Asked Questions
Are blue mud wasps harmful?
Blue mud wasps are not typically harmful to humans. They are solitary wasps that primarily feed on nectar and pollen from flowers.
The female blue mud wasp will use her stinger to paralyze spiders, which she then lays her eggs on for her offspring to feed on when they hatch.
While the sting of a blue mud wasp can be painful, they are not known to be aggressive and will only sting if they feel threatened or provoked.
Overall, blue mud wasps are beneficial insects that help control spider populations and are not a significant danger to humans.
What do blue wasps do?
Blue mud wasps are a type of solitary wasp that are known for their unique nesting behavior.
They use mud to build their nests, which are typically located in sheltered areas such as under eaves or in crevices.
Once the nest is made, the female wasp will lay her eggs inside and then hunt for spiders to feed them.
These mama wasps can find and capture black widow spiders, which they then paralyze and bring back to the nest.
Despite their fearsome reputation, blue mud wasps are not typically aggressive towards humans and are considered to be beneficial insects due to their role in controlling spider populations.
What happens when a blue mud wasp stings you?
Wasp stings, in general, can be painful. They can cause swelling and redness.
The venom of the blue mud wasp contains toxins that can cause an allergic reaction in some people. Allergic reactions can be dangerous.
Some people might have extreme symptoms like difficulty breathing, hives, and even anaphylaxis in severe cases.
If you suffer from an allergy to insect bites and stings, you should seek immediate medical attention.
Treatment may include anti-inflammatory medication, antihistamines, and in some cases, epinephrine.
What kills blue mud wasps?
Birds and spiders are the most important predators of blue mud wasps. Larger insects can also attack them.
Humans, of course, are a major reason behind the diminishing populations of these beautiful creatures.
Pesticide use, habitat destruction, and climate change are three major reasons that kill wasps like blud mud daubers.
Pesticides not only kill the blue mud wasps but also affect their food sources, leading to a decline in their population.
Deforestation and urbanization limit the availability of suitable nesting sites and food.
Climate change alters the timing of the blue mud wasp’s life cycle, affecting its survival and reproduction.
Yes, blue mud wasps are a nightmare for spiders, including the poisonous black widows.
These wasps are excellent for removing pests like spiders and promoting pollination. However, they can sting if you threaten them. Do not try to manhandle them, and you will be fine.
If you find it annoying to deal with the mud nests around your house, use the tips mentioned in the article to get rid of them.
Thank you for reading!
Blue mud daubers are so unique in their appearance and so fearsome in reputation that we have often received queries from our readers about them in the past.
We have collected below some of the questions, our answers, and of course, a selection of beautiful photographs of these wasps.
Please go through it.
Letter 1 – Blue Mud Wasp
What is this???
My 4 year old son is a bug addict. We have been catching and taking pictures of every bug he finds so that we can release them after we have the picture. We then find them in one of our many bug books and keep the pictures in a special book for him. Problem is we can’t classify this one. Can you?
This may be a Blue Mud Wasp, Chalybion californicum, but you did not provide us with a location and that would have helped greatly. We will see if Eric Eaton can assist us. Eric provided this information: “You were right the first time:-) It appears to be a male Chalybion californicum, the blue mud dauber. Chlorion are slightly more robust, and a whole lot more shiny in images this well lit.”
Sorry, we are in Ontario Canada.
Letter 2 – Blue Mud Wasp
Blue Flying Bug (with pitchure)
Dear Bug man,
I have seen this bug for the first time this year (July/Aug 2006) Can you tell me what it is and if it is a harmful bug. I live in San Diego California, Ramona to be exact. I have also witnessed this bug in Payson Arizona. Thanks
Oddley Curious of San Diego
Dear Oddly Curious,
This is a Blue Mud Wasp, Chalybion californicum. The female provisions her nests with spiders, especially comb footed spiders.
Letter 3 – Mysterious Black Wasp Aggregation: Blue Mud Daubers
Please help me identify this bug
I live in south Texas and I have noticed these guys showing up at dusk and leaving in the morning all spring. At first they would land on one of my ferns in a hanging basket. They seemed to like one particular frond. I began to worry that the fern was being damaged, so I moved it away. That night they showed up and moved in on my ivy basket. This time they aren’t on the plant itself, but just the pot. There are so many on the bottom of the pot that it gives me the willies. I wish they would go away, but I’m not going to kill them. Any idea what they are? Thanks for your help.
The behavior you describe and have photographed is something we have encountered with the in the past, but those were striped wasps. BugGuide shows genus of black Tiphids, Tiphia, but we are not certain this is your insect. We will contact your namesake (and perhaps long lost cousin) Eric Eaton to see what he can add.
The image of the large aggregation of wasps depicts male (read STINGLESS) blue mud daubers, Chalybion californicum. The deep metallic color does not always show up well in photos, but this behavior is a real signature of the species. Males are anatomically incapable of stinging, so no worries there. They form these “bachelor parties” to spend the night, but for what reason is anybody’s guess.
Letter 4 – Blue Mud Wasp
Metallic very large blue/black wasp Location: Fairfield, Maine USA August 9, 2010 12:06 pm Dear Bugman, I saw this large iridescent thing wizz by me out in the meadow. I was able to track it down and get a few pictures before it flew away. Is this a Steel Blue Cricket Hunter (Chlorion aerarium) or maybe a Blue mud Wasp? I cannot tell so far. It was quite large, I dare even guess 2 inches long. It is also very active and almost never came to a full ”stop.” it is beautiful, but can/will it sting a person? Thank you! James R Hi James, Nice job of narrowing down the identification of this lovely Thread-Waisted Wasp. In the past, we frequently mixed up the two, but now we are usually correct. We believe this is a Blue Mud Wasp, Chalybion californicum, which if profiled on BugGuide where it is described as: “A large, active, blue-black wasp with irridescent blue wings. Frequents flowers for nectar and buildings for nest sites. Compare “Steel-Blue Cricket Hunter”, (or “Blue Mud Dauber”), Chlorion aerarium, which preys on crickets. This is about the same size as Chalybion, and is said to have a longer pedicel (narrow waist between thorax and abdomen). The body of Chalybion looks much more hairy, and more steely-blue, based on specimen photos.“ BugGuide also indicates: “Females construct mud nests in sheltered areas, often under the eaves of buildings, and provision them with spiders. Sometimes refurbishes the nests of other mud-daubers, such as Sceliphron.” We love that you have abbreviated your photos as “BMW”. Hi Daniel, Thank you so much for the identification. I kept going back and forth and finally just had to ask the experts! Best wishes, James Awesome James. Be sure to let us know what the experts think.
Letter 5 – Great Black Wasp
Subject: Which Wasp? Location: Long Island, NY August 26, 2013 3:51 pm I could not identify this one here or at BugGuide. A little more help, please? Signature: Carl Hi Carl, We believe this is a Blue Mud Wasp, Chalybion californicum, but we are not certain. We will try to get a second opinion. See BugGuide for photos of the Blue Mud Wasp. The iridescence of the wings is only visible in your second photo. Eric Eaton provides an identification: Male Great Black Wasp I’d say a male Great Black Wasp, Sphex pensylvanicus. Eric
Letter 6 – Blue Mud Wasp
Subject: Blue Bug? Location: Philadelphia, PA July 1, 2015 11:10 am Location: just outside of Philadelphia, PA Date: 6/29/15 Summer Time: 9:15 am I have a gift for finding strange bugs. Two different Sphynx Moths, odd grasshoppers, albino spiders and such. This is my first blue bug. 🙂 Signature: Andrea Dear Andrea, This is a Blue Mud Dauber or Blue Mud Wasp, Chalybion californicum. According to BugGuide: “A large, active, blue-black wasp with irridescent blue wings. Frequents flowers for nectar and buildings for nest sites.”
Letter 7 – Blue Mud Wasp
Subject: Iridescent Wasp? Location: Cabot, VT July 17, 2016 8:03 am I just found this beautiful wasp-like flying bug, dead in my upstairs window (July). I live in central Vermont, in an old farm house surrounded by cow pastures and woods. We have a small second floor attic space, and I’ve seen both evidence of old wasp nests on the ceiling in there, and live wasps flying out of there. I haven’t seen one like this alive, though. I’ve never seen anything like it, even though I’ve lived in a number of New England farm houses throughout my life. I love your website, and I’m so excited to finally have a bug to send to you! Signature: Lara Dear Lara, This looks to us like a Blue Mud Wasp, Chalybion californicum, a species described on BugGuide as: “A large, active, blue-black wasp with irridescent blue wings. Frequents flowers for nectar and buildings for nest sites.” BugGuide also states: “Females construct mud nests in sheltered areas, often under the eaves of buildings, and provision them with spiders. Sometimes refurbishes the nests of other mud-daubers, such as Sceliphron.”
Letter 8 – Common Blue Mud-Dauber Wasps
Subject: Black Flying Insect Geographic location of the bug: Upstate New York Date: 07/20/2021 Time: 06:56 PM EDT Your letter to the bugman: Helli, We have these insects around our deck for the first time this year. We have lived here for 30+ years. Are they wasps, hornets or something else? Thank you! How you want your letter signed: Susan Dear Susan, We believe these are Common Blue Mud-Dauber Wasps,Chalybion californicum, which are pictured on BugGuide. According to BugGuide: “A large, active, blue-black wasp with irridescent blue wings. Frequents flowers for nectar and buildings for nest sites.” and “Females construct mud nests in sheltered areas, often under the eaves of buildings, and provision them with spiders.” We suspect they are searching for mud near your deck for nest building.