Ensign Wasp (Evaniidae) from Cambodia. These unusual-looking parasitic wasps lay their eggs inside cockroach oothacae (egg cases), which hatch into hungry larvae that consume the roach's eggs.
Ichneumon wasp (Ichneumonidae: Cryptinae) from Wisconsin.
Most Pseudomyrmex ants (like this one from Costa Rica) are twig nesters, seeking refuge in the hollow stems of a variety of plants. Some have even evolved obligate mutualisms with Acacia trees, defending them from competitors and herbivores in exchange for nectar and protein-rich excretions called Beltian bodies.
