San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide

Dasymutilla sp.
Velvet Ant

MUTILLIDAE

Description

Velvet Ants are actually not ants at all. They are solitary, wingless wasps. They can be differentiated from true ants in having only a slight constriction, or pedicel, between the abdomen and thorax and in having antennae that are not elbowed. Females are most frequently seen. Male Velvet Ants are fully winged and are seldom discovered. Velvet Ants are venomous insects. They have docile dispositions, but will inflict a painful sting if mishandled.

Size: Velvet Ants come in a variety of sizes ranging from 1/4 to 7/8 inches (6 to 20 mm) in length. Some individuals can measure up to one inch.

Coloration: Velvet Ants are black bodied insects covered with a thick coat of delicate hairs in a striking array of colors: red, orange, red with black, cream and white. One species, the Thistledown Velvet Ant (Dasymutilla gloriosa), has a cream colored coat with long strands of hair dispersed throughout.

Range and Habitat

Velvet Ants can be found in California, Utah, Nevada and Texas into Mexico. Although the majority of the species found in our region frequent our deserts and foothills, they also exist in our coastal habitats.

Natural History

Velvet Ants are visually stunning insects to happen upon in the field. Despite their "soft" appearance, these wasps have extremely hard exoskeletons enabling them to withstand the stings of many varieties of bees and wasps. Velvet Ants parasitize other ground dwelling wasp or bee nests. The female wasp spends much of her time on the ground searching for burrows in order to deposit her egg(s). Depending upon the species, the developing Velvet Ant brood will feed upon the larvae of the wasp or bee, or the stockpile of food left for the unsuspecting wasp or bee. In California, we have about 100 species of Mutillidae, most of which are nocturnal and live in our deserts. Adult Velvet Ants feed on nectar in the wild. At the Museum we feed them honey, bee pollen, grapes and fresh flowers.

Velvet Ant (Cow Killer) copyright Troy Bartlett
© 1998-2001 Troy Bartlett

The species pictured here and featured live in our exhibit, Natural Treasures: Past and Present, is Dasymutilla occidentalis, or Cow Killer. It can be found from New York to Florida and the Gulf states, west to Texas. This particular wasp gets its common name from its ability to fight ferociously and inflict a sting so severe that it is said to be able to kill a cow.




Did you know?
Velvet Ants are very good at climbing glass. They are also very skilled in the art of burrowing to avoid detection. When disturbed, they produce a very audible high pitched squeaking sound. This same identical sound can be heard when working with harvester ants (Pogonomyrmes spp.)

Text by Jennifer Costelow.
Photograph © 1998-2001 Troy Bartlett used with permission

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