Velvet ants are actually solitary wasps, classified into the order Hymenoptera
and family Mutillidae. Thus they only superficially resemble ants. Ants
and wasps differ in the shape of the region between the thorax and abdomen
and the shape of the antenna, the former have a definite bend or elbow
in their antenna. There are several hundred species of velvet ants in
North America. Most have pronounced hairs (velvet nature) that are often
brightly colored in various combinations of red, orange, white, and/or
The females are wingless and are capable of inflicting a painful sting
and bite if provoked. The bright coloration of velvet ants is probably
an advertisement to potential predators of their formidable defenses.
The intensity of the sting may be the origins of the common name "cow
killer". Although the sting injects venom the dosage and toxicity
is quite limited and is not enough to kill a human or a cow.
The adult females are found roaming in environments with sandy soils.
They are usually seeking out the ground nests of other bees and wasps,
both solitary and colonial species. The female will invade the nest and
lay her egg near the host species' egg or larva. When the eggs of the
velvet ant hatch, the larva will then feed on the host's brood. They will
later pupate and then leave the nest as an adult. The males are winged,
lack a stinger, and are known to feed on nectar. It is suggested that
females will feed on contents within the nest of their host, either stored
food or the larvae.
When disturbed, velvet ants will produce a faint but audible sound. The
sound is thought to be primarily a warning signal used in defense, which
may reinforce the visual signal from the body coloration. Like other species
of Hymenoptera, the sound is produced by the rubbing of two abdominal
segments together, the edge of one segment acting as a file and the other
edge acting as a scraper (see scanning electron micrographs below). This
type of sound production is known as stridulation.
Our research is focused on describing the mechanism of how this sound
is produced and the conditions that will provoke a response. The file-scraper
structure responsible for the stidulation is found in most of the abdominal
segments but particular segments may be responsible for producing different
elements of the sound. Future studies will focus on the following questions:
1. What is the relationship between
the individual abdominal segments and different acoustic components of
2. What conditions will elicit stridulation
and what are the benefits of this behavior?
3. How do the acoustic signals and
behavior vary among the different species found in the southeast?