|Dasymutilla erythrina, D. gloriosa, D. sicheliana, all female|
|Dasymutilla sicheliana male|
|Dasymutilla occidentalis (Cow Killer) from Eastern US, photo Barry Marsh|
|Social wasps, Polistes sp. colony|
Mutillids are neither social nor do they store larval food or even have their own nests. Their larvae develop as Ectoparasitoids of immature insects, esp. bees and solitary wasps (also flies, limacodid moths, beetles, and cockroaches). So the mutillid wasp is not guarding or defending those nests or larvae. There are many other solitary wasps like Scoliids, Cicada Killers, and Mud Daubers etc. with comparable developmental histories that are not known for an especially painful sting.
|Male nocturnal Mutillid|
Some species of mutillids also release chemical defenses when caught. In addition, all of them, winged males and fast-footed females, are so heavily armored that they survive unharmed when swatted at or stepped on - even when chewed on by a naive predator I assume. This extra strong exoskeleton must be costly to build and heavy to carry. Justin Schmidt also mentions that the legs of a female mutilid are about as strong and muscular as insect legs can get. That's easy to believe when you see them running. So these wingless wasps have a defensive arsenal that is not equaled by many other insects.
The majority of insects has a very short adult life span. After mating, females of many species lay hundreds of eggs in one big clutch on a host plant and then die. Even big wasps like Cicada Killers that provide food for their offspring don't live much longer than 40 days. Mutilid wasps are parasitoids of solitary bees or wasps. Their arid habitats are bare and thinly populated by any host species. Mutilids procreate by placing single eggs into late instar larvae or pupae of their host species. So even if the female Mutilid finds a leafcutter nest with a series of larval chambers, there might only be one or two that fits her requirements. So her egg production may be strung out over a long time and depends on her searching for just the right situation to lay one egg or a few. This is possible because her adult life span, amazingly, is longer than a year. This longlevity ensures that the female has time to place enough eggs to guaranty the survival of the species. The arsenal of defensive weapons provides the means necessary to survive that long.
|With Justin Schmidt and his family: searching for mutillids and other arthropods in the dunes along Blue Sky Road in Willcox, AZ in July of 2017|