Velvet Ants – The Wasp in Disguise

It’s a Bird! It’s a Plane? It’s an… ant?!”

Scientifically referred to as the Dasymutilla gloriosa, the thistledown velvet ant has an extremely misleading name – most notably because it isn’t an ant at all. The curious insect native to the Mojave Desert is white in color and has long silky setae (a type of hair). They are surprisingly similar in appearance to another natural entity of the desert: the fruit of the creosote bush. These tiny furry orbs can easily be mistaken for the velvet ant, which is why entomologists originally theorized that the wasp developed its appearance for the sake of camouflage.

Eventually, Dr. Wilson of Utah State University decided he was going to find out for sure if this was the reason for the curious look of the wasp. “I had to know,” Dr. Wilson said. “Why was this wasp white?”

A Curious Appearance

By tracking the evolution of the creosote bush using fossil records, Dr. Wilson was able to deduce that the wasps could not have evolved to mimic the desert foliage. Originally from South America, the creosote bush did not make its way into the Mojave Desert until around 100,000 years ago, which he determined was an insufficient length of time for the wasp to evolutionally undergo such a drastic and complete appearance upheaval. With the old, accepted theory debunked, Dr. Wilson set out on a deep exploration into the species.

After ten years of research, Dr. Wilson and his team of scientists believe they may have discovered the true reason for the velvet ant’s curious visage: temperature control. With the capability of reaching 120 degrees Fahrenheit, the Mojave Desert presents an unforgiving and brutal environment. In order to survive turbulent environment, the wasps appear to have adapted to regulate their boy temperatures using the white furry-like setae. The white color reduces the amount of light absorbed by the insect, thereby keeping it cooler, while the thistly setae bounces the light away from them, increasing their ability to deflect the scorching heat.

Some scientists have argued that while the temperature management due to the wasps’ odd appearance may be true, the similarity between the creosote fruit and the velvet ant is so exact, that there has to be a correlation. While Dr. Wilson stands behind his research regarding the evolution and migration of the creosotes arriving too late to be the catalyst for the wasps’ appearance, he does concede that it may have definitely reinforced or even encouraged the species’ evolution to become even furrier and whiter. Furthermore, as part of his counter argument for correlation, not causation, Dr. Wilson points out that, “just because something looks like a leaf, doesn’t mean it must look like a leaf to everything.” Within the animal kingdom and insect empire, the world is perceived very differently and when the wasps and creosote fruit are observed with Ultraviolet light, which is how some insects observe the world, the two look drastically different.

Why the Misnomer?

There are actually several different sub-classifications of velvet ant, scientifically known as the family Mutillidae within the Hymmenoptera order. This study specifically covers the Dasymutilla gloriosa, but there are many different kinds of these wasps masquerading as ants. The most common Mutillidae is the Dasymutilla occidentalis, also known as the “cow killer ant.” It is so named because its sting is said to be so painful it could kill a cow. These wasps have two unique features that resulted in their curious name – the first and most obvious being their fuzzy exteriors. In addition to this, the female wasps of the species lack wings, resulting in them walking about just like ants and accounting for the curious name. Watch out though, even though they may be wingless these wasps still pack a powerful sting

Citations

Green, J. (2017) Velvet Ant (Cow Killer Ant), The University of Nebraska-Lincoln. The Institute of Agriculture and Natural Resources – Nebraska Extension in Lancaster County. Available at: https://lancaster.unl.edu/pest/resources/velvetant.shtml (Accessed: August 2020).

Imbler, S. (2020) How a Velvet Ant Got Its White Fluff, The New York Times. Available at: https://www.nytimes.com/2020/07/14/science/white-fluffy-ant-wasp.html (Accessed: August 2020).

Thistle Down Velvet Ant (Dasymutilla gloriosa) (2019) Insect Identification. Available at: https://www.insectidentification.org/insect-description.asp?identification=Thistle-Down-Velvet-Ant (Accessed: August 2020).