The diet of the creature commonly known as the Cow Ant changes completely depending on its stage of life. This shift in feeding habits is necessary for survival as the insect transitions from a developing grub to a fully formed adult. What it consumes provides either the energy required for its nomadic adult life or the concentrated protein needed for its rapid larval growth.
Understanding the Velvet Ant Misnomer
The creature often called the “Cow Ant” or “Cow Killer” is actually a type of wasp, not a true ant, belonging to the family Mutillidae. The common name exists because the wingless females are covered in a dense, velvety coat of hair, making them look superficially like large, fuzzy ants. The most well-known species, Dasymutilla occidentalis, is the largest velvet ant in the United States.
The velvet ant progresses through four distinct life stages: egg, larva, pupa, and adult. The adult male possesses wings and resembles a typical wasp, while the female is wingless and possesses a powerful stinger.
The two primary life stages—the adult and the larva—have entirely separate dietary needs. The female searches for a host for her young, while the male focuses on reproduction and energy acquisition.
Sustenance for the Adult (Energy Sources)
The adult velvet ant’s diet centers on acquiring simple carbohydrates to fuel its active, solitary existence. Both males and females primarily feed on sugar-rich liquids, such as nectar consumed directly from blossoms. Nectar is a concentrated source of sugars that powers the adult’s movements, including the female’s searches for a host nest and the male’s flights.
Adults also feed on other sweet liquids they encounter, such as tree sap exuding from damaged bark. Some species consume honeydew, the sugar-rich excretion left behind by sap-sucking insects like aphids. This energy-focused diet prepares the female for reproduction and provides the male with the energy to mate.
The Parasitic Larval Diet (Protein Sources)
The larval stage relies on a high-protein source obtained through a specialized parasitic process. Female velvet ants are brood parasitoids, seeking out the nests of other insects to lay their eggs. They target the developing young of ground-nesting solitary bees and wasps.
The female invades a host’s nest, often an underground burrow, and deposits a single egg near or directly on the host’s mature larva or pupa. Common hosts include the immature stages of solitary bees (like bumblebees) and various solitary wasps (including mud daubers and cicada killers).
Once the egg hatches, the larva is a pale, legless grub that immediately begins to consume its host. This process is a form of ectoparasitoidism, where the larva attaches to the outside of the host and feeds on its tissues.
The larva consumes the entire body of the host, which provides the necessary complex proteins and fats for its rapid development. After consumption, the larva pupates within the host’s empty chamber, completing its transformation into a new adult.