This week we revisit a fearsome and beautiful insect first introduced in August, 2006, the velvet antDasymutilla occidentalis. Over the past months, several calls and letters arrived at Bug of the Week inquiring as to the identity of the large red and black ant seen cruising along the ground. This remarkable insect is not an ant at all. It is a wasp and more closely related to the tiphiid wasp that attacks Japanese beetle grubs such as the one we met in “Roses beware Japanese beetles are in the air, Popillia japonica” on July 11, 2005 than the ants we visited in “Field ants to the rescue- Formica sp.” on May 16, 2006.
Wow! With a stinger like that, no wonder she is called a "cow killer".
The female velvet ant featured this week was discovered in a commercial nursery in Adamstown, Maryland. Reports of velvet ants originated in Pasadena, Queenstown, and Bowie. Although lacking wings, the velvet ant is no slow poke. She runs like a demon searching the ground for a nest of unsuspecting bumble bees. Her powerful jaws and terrible stinger probably allow her to fight her way past bumble bee defenders and enter the brood chamber of the bee hive. In the brood chamber bumble bee larvae are nourished and cared for by bee workers. The velvet ant lays a single egg on or near the bumble bee babes. This egg hatches into a velvet ant larva that consumes the developing bee. When it has completed its development, the larva forms a pupa and later emerges as an adult velvet ant.
Natural Defenses
Male velvet ants have wings that are shiny and jet black. The males fly about in search of food such as flower nectar and pollen, and mates. The lovely female velvet ant in this bug of the week emitted a clearly audible squeaking sound when she was captured. Squeaking is accomplished by rubbing one part of the body against another. What purpose does the squeaking serve? Along with the bright red and black coloration, the loud squeak probably serves as a warning to any would-be predator that this beauty packs a punch. You see, the other common name for the velvet ant is “cow killer.” When I grabbed this one with a pair of forceps, an enormous, angry stinger was thrust out of the tip of her abdomen in search of something to punish. Some say that the sting of a velvet ant is strong enough to kill a cow. While this surely never happened, people stung by the velvet ant report that it was memorable indeed.
References:
We thank Dan and Marcia for providing the inspiration for this Bug of the Week and Paula for risking an awesome sting while capturing the subject for this episode. The beautiful National Audubon Society Field Guide by Milne and Milne was used as a technical reference for this Bug of the Week. To learn more about velvet ants, please visit the following web site.