Aphid-associated
Guides
Omalus
cuckoo wasps, jewel wasps
Omalus is a genus of cuckoo wasps (family Chrysididae), commonly known as jewel wasps for their metallic coloration. These small parasitoids employ a distinctive reproductive strategy: females insert eggs into living aphids at the hunting sites of their host wasps, using the aphid prey as an unwitting vehicle to transport their offspring into host brood cells. This indirect nest-entry strategy avoids the need for adult wasps to physically enter host nests. The genus includes multiple species across Europe, Asia, and North America, with some introduced species established in the United States.