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Red Velvet Ants
Naturalist(s): W.J. Davis
Date: Summer 2012
Location(s): Rothenbach Park, Sarasota, FL (map)
Rothenbach Park, Sarasota, FL

Field Notes
Among the family of velvet ants is a wasp called the “cow killer", which has conspicuous red coloration that presumably wards off potential enemies. Given that the venom of Dasymutilla occidentalis is measurably less toxic than that of honeybees and harvester ants, it is absurd to think that the sting of these noncolonial hymenopterans is lethal to vertebrates. Furthermore, females are nonaggressive and male velvet ants lack a functional stinger all together.

   Still, if handled or stepped upon, a female velvet ant will sting in self-defense. So perhaps the species' bright coloration does serve as a warning, enough to minimize the chance of being crushed from above. Unlike most wasps, female velvet ants cannot fly and spend most of their time searching the ground for nursery burrows of insects, such as digger wasps and bumble bees. When a burrow is located, a female will dig down to the host's pupa and lay an egg.* Given that suitable burrows in which to lay her eggs are either well hidden and/or widely distributed may explain why a female is so active in her search.

   In Florida, I have encountered females of several species of velvet ants and all lacked wings. Males, on the other hand, can fly, which is an ability that presumably helps them locate females. In their nuptial search they fly back and forth over promising terrain while frequently landing to sample the air for pheromones released by receptive females.

   On only one occasion have I seen males in the field. In this instance, one bright red and one reddish brown male fought over a small plot of ground. Frequently, the red male would land and begin to dig in the sand. I doubt if he was searching for food, however, as adult velvet ants prefer to dine on nectar. I suspect that both of the males were attracted to the scent of a virgin female that was about to emerge from a burrow.

   I would like to know if females mate with more than one male and whether males depend more heavily on chemical communication than vision to locate potential mates. We do know that velvet ants exhibit a haploid-diploid genetic arrangement with males possessing only half the number chromosomes as females. *The female may lay an egg next to or inside a pupa's body. There are conflicting reports in the literature.