Velvet ants are not ants at all; they are wasps in the family Mutillidae. Although more common in the southwestern U.S., they can be found throughout the Southeast. Forty-one species in six genera occur in South Carolina. Of these, the most common species is Dasymutilla occidentalis or the eastern velvet ant. Because of its large size (3/4 inch) and painful sting, this species is also known as “cow killers” or “cow ants”. Although there is nothing to indicate that any cow has ever been killed by one, cows are most likely rarely stung.
Figure 1. Dasymutilla occidentalis, the eastern velvet ant.
Photo by Johnny N. Dell, Bugwood.org.
Figure 2. Pseudomotheca oculatus, another velvet ant species found in the southeastern U.S.
Photo by Jessica Louque, Smithers Viscient, Bugwood.org.
Figure 3. Velvet ant males typically have black wings.
Photo by Johnny N. Dell, Bugwood.org.
They are called “velvet ants” because both males and females are covered by dense, velvety pubescence with brilliant patterns of black with red, yellow, or orange. The wingless females are most often seen scurrying quickly across the ground, while the winged males are not usually noticed. Although winged males are harmless, wingless females can inflict a severe sting. The sting, though extremely painful, is rarely dangerous. Their nickname of “cow killers” is undeserving. Their bright coloration acts much like a yellow or red traffic light, giving a warning of possible danger. Velvet ants may also produce a squeaking sound when disturbed, which also acts as a warning. The sound is produced by rubbing parts of two abdominal segments across one another.
Velvet ants may be seen during the warm periods of the year. In South Carolina, they are common from about May through September. They are most often seen during cooler daylight hours, especially late afternoon.
Velvet ants are parasites of other insects, especially ground-nesting bees, wasps, and sometimes flies and beetles. Females lay their eggs individually upon the immature stages of their host. The parasite then develops at the expense of the host, eventually killing it. Adults feed on nectar from flowers.
Velvet ants are rarely plentiful enough to become a nuisance and pose no real threat to people, pets, or livestock. They usually remain outdoors, though they may very infrequently be found in dwellings. While adult velvet ants are not aggressive, they should never be picked up by hand or stepped on with bare feet. Due to an extremely tough integument (outer covering or exoskeleton), neither chemical nor mechanical control is very effective. Careful removal of the insect to a more desirable location is the control method of choice. Or, if they are not hurting anything or anyone, it’s best just to leave them alone.
Originally published 01/98
