SUMMARYSemen and eggs fromApis mellifera monticolacolonies, collected at 3 500 m above sea level on Mount Elgon in Kenya, were brought to Sweden. Queens were raised from the imported eggs and inseminated with the imported semen. From the inseminated queens, pure Am. monticoladaughters were raised and inseminated with semen fromA. m. ligustica.Daughters of these F1hybrids were again inseminated with pure A m. monticolacent by 0.75 to theA. m. monticolastock. The development of inducedVarroa jacobsoniinfestations (282.0±20.9 mites,±s.e.,n= 5) was investigated in hybrid colonies and compared to the development inA. m. ligusticacolonies (controls). The percentage of infertileVarroafemales in infested cells was higher (P0.05,t-test). The length of the post-capping period was not investigated separately, but in combs frommonticolacolonies bees began to emerge from cells 19 days after egg-laying, as opposed to 20 days in theligusticacombs. At the end of the experiment, 101 days after mite introduction, the hybrid colonies contained 390.8±98.5, and the control colonies 1354.5±91.0, mites (±s.e.). The negative characteristics reported forA. m. scutellatax EuropeanA. melliferahybrids, such as agressiveness and absconding, were not seen in themonticolahybrids, and the potential ofA. m. monticolain selection work forVarroamite resistance should be evaluated.