There are many rumors floating around concerning the potent venom produced by the so-called “cow-killer ant”. Contrary to this insect’s common nickname, it is neither an ant nor a killer; instead, these insects are actually a wingless wasp species that closely resemble ants. These wasps are also commonly known as velvet ants, and they belong to the Mutillidae family, which consists of more than 400 species within the United States alone.
If these wasps were actually capable of producing venom that could kill a cow weighing more than a ton, then they could certainly kill a human being. While these wasps are not recognized as killers, they are known for inflicting one of the most painful stings of all arthropod species. Perhaps the most notorious species is Dasymutilla occidentalis, which can be found in several states within the US, including Massachusetts. D. occidentalis is commonly referred to as the eastern velvet ant, and this species can be found in sandy coastal areas, fields, meadows, forests, and unfortunately, residential lawns.
In addition to D. occidentalis, the D. lepeletier and D. bioculata species have also been spotted within Massachusetts. The adult D. occidentalis grows to be around three fourths of an inch in length, and specimens are easily recognizable for their fuzzy orange-brownish exterior featuring black stripes. These wasps may be better suited for defense against potential predators than any other wasp species, as studies have demonstrated that an array of much larger animals, such as birds, lizards, moles, shrews and many others, are incapable of digesting these insects. This is due to defensive chemicals that the wasps secrete after being swallowed by larger animals. The chemicals cause the animals to regurgitate the still-living wasps, making this group of wasps virtually predator-free. The toad is the only animal predator capable of digesting D. occidentalis, but they often regret eating them in the first place, as they still experience pain. The Schmidt’s Pain Index, which ranks the pain of an insect bite or sting on a scale of 1 to 4, with four being the most painful, D. occidentalis is ranked as a three. In other words, the stings inflicted by these wasps are extremely painful, and simply stepping on a specimen in your backyard will result in a memorable sting. Despite their painful sting, D. occidentalis venom is not too toxic for humans, and medical attention is rarely necessary upon sustaining a sting.
Have you ever spotted a velvet ant within your backyard?