Digger Wasps are predators that can sting and paralyze prey insects. In preparation for egg laying they construct a protected "nest" and then stock it with captured insects. Typically the prey are only paralyzed by wasp toxins. Most species in this family dig nests in the ground or use preexisting holes. The mud dauber wasps builds nests from mud. The wasps lay their eggs in the provisioned nest. When the wasp larvae hatch from the eggs, the insects provide food for the growing larvae.
Here, this Steel-blue Cricket Hunter (Sphex pensylvanicus)struggles with its prey.
Another species of digger wasp is the Great Golden Digger (Sphex ichneumoneus) which is found in North America. The developing wasps spend the winter in their nest. When the new generation of adults emerge, they contain the genetically programmed behavioral abilities that are required to carry out another season of nest building. During the summer, a female might build as many as half a dozen nests, each with several compartments for her eggs. The building and provisioning of the nests takes place in a stereotypical, step-by-step fashion.
Some of these wasps drop a paralyzed insect near the opening of the nest. Before taking provisions into the nest, the adult wasp first inspects the nest, leaving the insect outside. During the wasp's inspection of the nest an experimenter can move the insect a few inches away from the opening of the nest. When the adult emerges from the nest ready to drag in the insect, all bets are off. The adult quickly finds the moved insect, but now the behavioral program has been reset. After dragging the insect back to the opening of the nest, once again the adult is compelled to inspect the nest, so the insect is again dropped and left outside during another stereotypical inspection of the nest. This iteration can be repeated again and again with the adult wasp never seeming to notice what is going on, never able to escape from its genetically programmed sequence of behaviors. Douglas Hofstadter and Daniel Dennett have used this mechanical behavior as an example of how seemingly thoughtful behavior can actually be quite mindless, the opposite of human behavioral flexibility that we experience as free will.