Thistledown Velvet Ant: An Evolutionary Mystery Solved

In this article we talk about the thistledown velvet ant, a unique wasp whose evolutionary story will leave you astounded!

If you walk around the desert regions of the Southwest part of the US, you might spot several creosote bushes with white fuzzy flowers lying near them.

You may be tempted to touch and pick one of them, but you must not do it without looking carefully: because it might be a dangerous stinging wasp!

Yes, we are talking about the thistledown velvet ant, which looks exactly like these flowers.

The wasps have a similar white and fuzzy appearance and can sting humans, causing incredible pain.

In this article, we will talk about them and the incredible story behind their evolution.

What Are Thistledown Velvet Ants?

Thistledown velvet ants (Dasymutilla gloriosa) are a type of wasp that is widely found in the desert areas of the Southwest regions of the United States.

The wingless females are fluffy and white; their movement is similar to ants, like other American velvet ants.

These insects mimic the texture of the scrubby creosote bushes as it helps them to blend with the surroundings and stay safe from predators.

However, evolutionary biologists have discovered that this is not the reason why they have taken on this white-colored form.

There is another big advantage that these features provide to the insect, which we will talk about in later sections of this article.

What Do They Look Like?

The male thistledown velvet ants are usually orange and black in color, and they have wings.

The females have a white coloration that resembles the creosote fruit. They have a long stinger and no wings.

These insects can show an average growth of 0.51 to 0.62 inches in length and like to be in dry and hot environments.

The Mystery Behind Their White And Fluffy Exterior

Till recently, entomologists believed that the fluffy exterior of these insects has evolved because it is very helpful for them to blend with their surroundings and stay protected from predators.

However, through several experiments, it was discovered that the fluffy and spiky coat on their body prevents the body from getting overheated in the dry and harsh conditions of the desert.

Biologist Joseph Wilson and his team came across this unique discovery and published the findings recently.

It all started when Dr. Wilson discovered that these insects have been living in North America for around 5 million years.

However, fossil records show that the creosote bush emerged during the Ice age. It must have taken around 100,000 years for them to become well-established in the Mojave region.

Dr. Wilson understood that it was not possible for the wasp to have developed these features in a mere 100,000 years; it had to have happened before the creosotes came to be.

In their experiments, they studied various parameters of the insect and discovered that it was extremely resistant to heat.

When compared to other insects, the thistledown velvet ant’s white and fluffy exterior keeps its internal temperatures several degrees cooler. This gives the insect a major advantage in the hot desert environment where it lives.

Moreover, their team also discovered that the spectral patterns of the thistledown velvet ant were different from creosote flowers. Even though humans cannot identify these spectral patterns, many insects can.

This meant that when other predators would look at this creature, they would easily be able to distinguish between this and a flower.

Hence the notion that their appearance was an advantage to camouflage it against predators had to be false.

Other Interesting Facts About Them

Apart from their fascinating appearance, these wasps have many other interesting things to note about them. Listed below are a few of them.

  1. Since male wasps can fly, it is a little easy for them to evade predators. But, the females do not have the ability to fly, which is why they have stingers to defend themselves. A thistledown velvet ant sting is highly painful and is a great tool to keep predators away.
  2. Unlike the females, the males don’t have a stinger, and they entirely rely on the flying ability to escape dangers.
  3. The females never build their own nests; they often lay eggs in other insects’ nests next to the pre-existing eggs. Once the larvae come out, they eat the pre-existing eggs, larvae, and pupae of the host. Thus, these wasps are parasitoids in nature.
  4. The females are mostly harmless, but they can sting humans, which will cause intense pain. The victim can experience problems like irritation, redness, and swelling near the wound.

Frequently Asked Questions

Are velvet ants poisonous?

Different species of velvet ants can deliver intensely painful stings to humans. But thankfully, these stings are not toxic or dangerous enough to cause any fatal injury or illness.
The victim might face temporary problems like redness, swelling, and irritation.

Can you touch a velvet ant?

Since the male velvet ants lack stingers, it is okay if you touch them. But you should avoid touching female velvet ants.
They are capable of delivering painful stings. You can identify a male by the presence of wings. The females are wingless and look very similar to ants.

Is a cow killer a velvet ant?

Cow killers are also known as velvet ants. These insects are a species of wasps and are usually found in open and dry areas.
The name cow killer is just an indication of how painful the stings of these insects are. There is no evidence of velvet ants attacking cows and killing them.

What eats a velvet ant?

Velvet ants are usually attacked and consumed by predators like toads, lizards, birds, and shrews.
To keep these predators away, they highly rely on the stinger and their body color, which helps them appear unappealing to such potential predators.
They also make a screeching noise to warn the predators when they sense danger.

Wrap Up

Thistledown velvet ants are difficult to spot in a scrubby creosote bush due to their fuzzy white appearance.

There was a notion that this camouflage helps them to stay safe from attackers like lizards and birds, but with the studies conducted by Joseph S Wilson, it is clear that it has evolved this feature for an entirely different reason.

The white, fuzzy exterior enables them to remain internally cool in extremely hot desert regions.

This later helps them to reach more host nests to lay eggs. We hope this article helped you to understand these fascinating insects better.

Thank you for taking the time to read the piece.

Reader Emails

The story of the evolution of the thistledown velvet ant is as unique as it is interesting.

Many of our readers have been interested in this wasp because of its unique, nearly perfect mimicry of the creosote flowers – but it turns out that it was never trying to mimic them at all!

Read the emails below to learn more about some of the conversations we have had around this bug!

Letter 1 – Not Thistledown Velvet Ant

 

The bug looks like David Bowie
Dear bugman,
I’m told you may be able to tell me what it is. I live in Southern California, silverado canyon to be exact (it’s on the edge of the cleveland national forest). It was a few months ago, this bug (pic attached) wondered onto our property. We see alot of strange spiders and bugs of sorts, but this one stumped us. It is 1/2 – 3/4 inches long. if you could tell me what kind it is i would be very greatful, we call it the David Bowie bug (since they share the same hair cut). We have not seen anything like it since that day.
Thank you,
Regina McIntyre



Hi Regina,
The Thistledown Velvet Ant does rather resemble David Bowie in his Diamond Dog days. This is actually a flightless female wasp.


Ed. Note Update: (12/02/2005)
ID corrections, etc. I’ve just discovered your excellent site (directed there by “This is True”), and as a hymenopterist have a few comments: All of the “thistledown velvet ants” shown are actually Dasymutilla nocturna, not Dasymutilla gloriosa. The latter has the erect hairs somewhat sparser and more “untidy”, the body is a reddish brown, not black, and all the hairs are whitish (no black hairs), so the legs look whitish.
I hope these comments are useful.
Denis

Update: (04/02/2008) ID for insects
Hey, my name is Will, this is a list of the ID’s for the velvet ant page. image 31. is Dasymutilla sackeni, Nocturna is a very ristricted species(Glamis, Algodones dunes). hope this helps a bit.

Letter 2 – Not Thistledown Velvet Ant

 

cool site!
Very interesting site. I have a couple of bugs I can’t identify. Both from Southern California. I appreciate any help you can give me.
Ron Drake



Hi Ron,
Your photos of the Thistledown Velvet Ant or Gray Velvet Ant, Dasymutilla gloriosa, are very nice. She is a female flightless wasp and can deliver a painful sting.


Ed. Note Update: (12/02/2005)
ID corrections, etc. I’ve just discovered your excellent site (directed there by “This is True”), and as a hymenopterist have a few comments: All of the “thistledown velvet ants” shown are actually Dasymutilla nocturna, not Dasymutilla gloriosa. The latter has the erect hairs somewhat sparser and more “untidy”, the body is a reddish brown, not black, and all the hairs are whitish (no black hairs), so the legs look whitish.
I hope these comments are useful.
Denis

Update: (04/02/2008) ID for insects
Hey, my name is Will, this is a list of the ID’s for the velvet ant page. image 37. Dasymutilla sackeni, D. nocturna restricted. hope this helps a bit.

Letter 3 – Velvet Ant

 

Velvet Ant and Unknown Spider Thistle Down Velvet Ant. I’m not really partial to blondes, but this little lady caught my eye in the parking lot at work in Poway, San Diego County. Don’t worry, I resisted the urge to pet her. I know she packs a painful stinger. I’m also including an unidentified spider. He was about the same size as a full grown green lynx, which are abundant in this area. Possibly another type of lynx? Love your site, Bernard Davis Hi Bernard, Thank you so much for your great photo of the Thistledown Velvet Ant, also known as the Gray Velvet Ant, Dasymutilla gloriosa. This is a new species for our site. The wingless female does have a painful sting. She wanders about on the ground searching for sand wasp burrows. She lays her eggs there and the young Velvet Ant larva then feasts on both the larval wasp as well as the food source of paralyzed flies the female Sand Wasp provides for her young. Male Velvet Ants fly. Ed. Note Update: (12/02/2005) ID corrections, etc. I’ve just discovered your excellent site (directed there by “This is True”), and as a hymenopterist have a few comments: All of the “thistledown velvet ants” shown are actually Dasymutilla nocturna, not Dasymutilla gloriosa. The latter has the erect hairs somewhat sparser and more “untidy”, the body is a reddish brown, not black, and all the hairs are whitish (no black hairs), so the legs look whitish. I hope these comments are useful. Denis Update: (04/02/2008) ID for insects Hey, my name is Will, this is a list of the ID’s for the velvet ant page. image 38. Dasymutilla sackeni hope this helps a bit.

Letter 4 – Thistledown Velvet Ants from Baja California, Mexico

 

Ant, white fur January 5, 2010 Found these ants on the beach of Nopolo about 5 miles south of Loreto. About 1/2 inch in lenght brillant white fur in the sun light. they appeared to be bits of white fluff blowing in the breeze. one of them bit me and it hurt like heck Kevin Kirkman Loreto Baja Sur California, Mexico
Thistledown Velvet Ant
Thistledown Velvet Ant
Dear Kevin, We are very excited to have a new species of Velvet Ant for our website.  This appears to be a Thistledown Velvet Ant, Dasymutilla gloriosa. Velvet Ants are actually flightless female wasps, and they can produce a painful sting.  We suspect you were stung and not bitten.   According to BugGuide:  “Female lays eggs in burrows of sand-wasps, such as Bembix. The larvae feed on larvae of the wasp and the food provided by the adult wasps. Pupation occurs in larval chambers of host.”  Back in 2005, we received the following correction for some Thistledown Velvet Ant images we erroneously identified:  “I’ve just discovered your excellent site (directed there by “This is True”), and as a hymenopterist have a few comments: All of the “thistledown velvet ants” shown are actually Dasymutilla nocturna, not Dasymutilla gloriosa. The latter has the erect hairs somewhat sparser and more “untidy”, the body is a reddish brown, not black, and all the hairs are whitish (no black hairs), so the legs look whitish.  I hope these comments are useful.  Denis”  Your Velvet Ants have erect sparse hairs and white legs, so we are relatively confident we are correct this time in saying they are Thistledown Velvet Ants.
Thistledown Velvet Ants
Thistledown Velvet Ants
Thanks for the info, interesting these are wasps not ants, they look like ants, I have more pictures if you want them just send me a email address to send them to, my thumb is still aching a day after being stung KK
Thistledown Velvet Ant
Thistledown Velvet Ant
Hi again Kevin, Thanks for sending additional images of these wonderful Thistledown Velvet Ants in their natural habitat.
Thistledown Velvet Ant
Thistledown Velvet Ant

Letter 5 – Thistledown Velvet Ant

 

Is it an ant? Thistledown velvet ant? April 18, 2010 Hi Bugman, thanks for this website! I found a strange insect in Baja California (Cabo Pulmo) and i think that he may be an ant. He was alone between stones. His abdomen mouved a little (up and down). One centimeter long. He looks like other pictures of “Thistledown Velvet Ant”. Can you tell me if i’m right? What a strange and beautiful animal!!! Sorry for my poor english, i’m french. Have a good day Niea Baja California Sur
Thistledown Velvet Ant

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