Caterpillars of Galleria mellonella (L.) and Achroia grisella (Fabricius), considered pests of beehives, were used to test host preference of the parasitoid Apanteles galleriae Wilkinson. On average, A. galleriae females originated from a lab rearing on both hosts preferred to parasitize caterpillars of A. grisella in 67% of the tests. The same experiment was repeated using A. galleriae females that had been reared during five generations in each of the host species, with similar results. A. galleriae females reared in caterpillars of G. mellonella parasitized A. grisella caterpillars in 64% of the tests, whereas the A. galleriae females reared in A. grisella parasitized the same species in 63.5% of the tests. This preference was not dependent on the number of host caterpillars used in each test. We conclude that A. grisella is a better host than G. mellonella to rear A. galleriae under laboratory conditions, and that the parasitoid is a promising natural enemy for the biological control of these species of wax moths because it can be easily reared in both species and none of these hosts show resistance to the parasitoid. Animals and man; Control; Biological control; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Achroia grisella; Galleria mellonella (Pyralidae ); Control by; Apanteles galleriae (Hymenoptera); Hymenopteran parasites; Apanteles galleriae; Host preference of parasite & significance for biological control Apanteles galleriae (Braconidae); Control of; Achroia & Galleria (Lepidoptera); Lepidopteran hosts; Achroia grisella & Galleria mellonella; Host preference & significance for biological control none