The Velvet Ant

Common Name:
Velvet Ant
Scientific Name:
Various
Class/Order/Family:
Insecta/Hymenoptera/Multillidae
Metamorphosis:
Complete

INTRODUCTION

These solitary wasps get their common name from the very hairy females which are wingless, often brightly colored, and look very fuzzy. However, they pack a very potent sting which has earned them the nickname of "cow-killer" and "mule- killer". Various species are found throughout the United States.

RECOGNITION

Adults about 1/8-7/8" (3-23 mm) long. Color black, with areas of often very bright red, orange, yellow, or white. Females wingless, antlike, but lack node on pedicel, densely covered with hairlike setae giving a fuzzy or velvet appearance, and with a long, smooth stinger. Males winged, wasplike, hairiness usually much reduced, coloring usually dull and different from females, and lack a stinger.

SIMILAR GROUPS

  1. Large bicolored ants (Formicidas) have pedicel with 1 or 2 nodes, at most with sparse hairs (setae), and antenna usually elbowed.

  2. Male scoliid/digger wasps (Scoliidae) have wing membrane beyond closed cells with numerous parallel wrinkles.

  3. Other wasps lack extreme hairiness and/or females with wings.

REPRESENTATIVE SPECIES

  1. Common eastern velvet ant Dasymutilia occidentalis (Linnaeus). Length about 5/8- 3/4" (16-18 mm); covered with black and red hairlike setae, female black with red except on extreme apex of metathorax and lst and 3rd abdominal segments, male black with red on pronotum, dorsum of thorax, and abdomen except for lst/basal segment; parasitic on bumble bee Bombus fratemus Smith; found in Connecticut to Maryland, southeastern U.S., Missouri, and Texas.

  2. Sacken's/Western velvet ant, Dasymutilla sackeni (Cresson). Length about 3/8-3/4" (I 0-1 8 mm); body black; covered with long white or yellowish hairlike setae except for legs and underside of body; parasitic on wasp Bembix occidentalis Fox; found in California, Oregon, and Nevada.

  3. California velvet ant, Dasymutilla califomica (Radoszkowski). Female length about 3/8-1/2" (8-14 mm); covered with brick-red hairlike setae; found in New Mexico, Colorado, Utah, and California.

  4. Pseudomethoca propinqua (Cresson). Length of female about 3/8-1/2" (8-12 mm), male about 3/8" (9 mm); color black except vertex (top of head) and apical/rear margins of abdomen with golden hairlike setae, wings of male dark; found in Minnesota south to Texas and westward to Alberta and California.

BIOLOGY

The larvae are external parasites on the larvae and pupae of primarily bees and wasps but also on a few species of beetles and flies. The female lays an egg on the prepupal or pupal stage of the host, her larva eats the host within a few days, and then spins its cocoon within the pupal case of its host. Most species of velvet ants are believed to be parasitic in the nests of wasps and ground-nesting bees, but some are thought to dig nests in the soil and provision them with insects. Some species are known to prey on honey bees. Females make a squeaking noise when held by the body; best held with forceps to avoid being stung.

HABITS

Females are typically seen running somewhat erratically on the ground, especially on bare or sandy areas; such areas are favored by many ground-nesting bees and wasps. They will occasionally enter structures for insect prey; observed in second- floor bathroom feeding on springtails (Collembola) by the senior author@ Males of some species are often found on flowers whereas, others are nocturnal.