Because of the dense hair on their bodies, these insects are called velvet ants and in some rural areas they are known as “cow killers.” This pair of velvet ants on Chico Basin Ranch shows the male (right) pursuing a female with the intention of mating. Velvet ants are not ants but actually solitary parasitoid wasps that mostly attack mature larvae or pupae of other solitary Hymenoptera (ants, bees, and wasps). Their sting is painful to humans but their venom is not strong enough to kill a cow or other mammals. The female velvet ant is wingless (left) and therefore she looks superficially like an ant. In contrast, winged males look like typical wasps. Females produce a painful sting but males have no stinger and are therefore harmless. There are over 200 species of velvet ant in the U.S. and Canada and the bright coloration of yellows, oranges, and reds is a good example of warning coloration.
Very rarely seen, here are multiple male velvet ants competing for one of the few females (photo of intertwined male velvet ants) and they are often found in large digger bee colonies which are common on Chico’s dirt roads (photo). A female velvet ant crawls down a digger bee’s burrow looking for a bee pupa where she tries to lay a single egg. After cutting through the hard outer skin of the ground nesting bee’s pupae, she lays an egg. However, before the velvet ant can do this the female must first kill the adult digger bee. The velvet ant larva spends the winter developing inside the bee larvae. In late spring the velvet ant pupae will emerge above ground and search for a mate and start the cycle again. This, then, is a good example of an insect’s complete life cycle: egg, larvae, pupae, and adult. Both male and female adults feed on pollen and nectar of nearby flowering plants during summer months.