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

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.