Two heritable traits of honey bees, hygienic behavior (HYG) and Suppression of Mite Reproduction (SMR) are important honey bee mechanisms of resistance to the parasitic mite, Varroa destructor. Both traits reduce the reproductive success of the mite: HYG reduces the total number of mite offspring when the hygienic bees detect and remove the infested pupae from the cells; SMR reduces the number of viable female offspring each mite reproduces; however, the factors responsible for this reduction in viable offspring are not known. Our studies indicated that bees selectively bred for SMR also demonstrate HYG. The aim of the present study was to understand the interplay between the two traits, to ultimately understand the mechanism of SMR. Our findings reveal that there are no significant differences in the proportion of mite-infested pupae detected and removed by SMR and HYG colonies; both lines removed 91 and 89% of the infested pupae, respectively. However, cross-fostring experiments, in which mites from SMR colonies were introduced into cells contaiing pupae withen SMR and HYG colonies revealed that SMR mites produce significantly fewer female offspring on their own pupae than they do on non-SMR pupae. Therfore, The SMR trait seemes to involve both the removal of infested pupae (HYG) and a reduction of reproductive success caused by some unknown factor related to SMR pupae.