An experiment was performed to test the influence of two factors on assortative mating in the Jewel wasp (Nasonia vitripennis): (1) inherited eye-color genotype, and (2) conditioned foraging phenotype. To determine the female choice of sires, genetically marked wasps were used of two recessive mutant eye-color genotypes: white or red. Each female (of independently crossed eye-color and juvenile host) was given a choice of two males, one of each eye-color, counterbalanced for juvenile host: blowfly (Sarcophaga bullata) or housefly (Musca domestica) pupae. Blowfly-reared females produced more total offspring, indicating higher fertility. Red-eyed females produced more offspring sired by red-eyed males, indicating assortative mating by eye color. Blowfly-reared females, however, did not produce more offspring sired by blowfly-reared males, indicating no assortative mating by juvenile host.