Hans Pfletschinger/Peter Arnold, Inc.
Cuckoo wasps are only seen occasionally due to their small size and secretive habits. However, in open, sunny habitats they are often abundant on flowers and small shrubs, where they feed on nectar. Cuckoo wasps often lurk near the burrows of their hosts, waiting for an opportunity to sneak in and lay an egg. They have a thick, hard cuticle (outer covering) that is covered with pits. The cuticle provides protection from stings and strong biting mandibles of host insects, which may attack the cuckoo wasp. In addition, the underside of the abdomen is concave and allows the wasp to roll up into a protective ball, another defensive mechanism. Although cuckoo wasps sting, their stinger is very small.
Cuckoo wasps can be divided into two chief types based on their lifestyles: parasitoids and cleptoparasites. Parasitoids feed on the larva of the host and cleptoparasites "steal" the host's food. In both cases the host larva dies. The food-stealing behavior of cleptoparasite species resembles that of the cuckoo bird and gave rise to the cuckoo wasp's name. Hosts of parasitoid species include bees, sphecid wasps, potter wasps, sawflies, silk moths, and the eggs of stick insects. Cleptoparasitic species feed on provisions of sphecid wasp nests, which may include dead spiders, true bugs, aphids, or thrips.
The Pacific cuckoo wasp parasitizes mason bees. The parasite's larva feeds on the bee's larva after the bee has spun its cocoon. The large blue cuckoo wasp, a cleptoparasite, lays its eggs in the nests of solitary wasps in the hornet family. The cuckoo wasp larva kills the host larva and eats the caterpillars that have been captured by the host for food.
Scientific classification: The cuckoo wasps are classified in the family Chrysididae, order Hymenoptera. The Pacific cuckoo wasp is Chrysis pacifica; the large blue cuckoo wasp is Chrysis coerulans.