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International audienceVarroa destructor is a parasitic mite of the Asian honey bee, Apis cerana. Owing to host range expansion, it now plagues Apis mellifera, the world's principal crop pollinator and honey producer. Evidence from A. mellifera in far-eastern Russia, Primorsky (P) originating from honey bees imported in the mid 1800's, suggested that many colonies were resistant to V. destructor. A controlled field study of the development of populations of V. destructor shows that P colonies have a strong, genetically based resistance to the parasite. As control colonies (D) were dying with infestations of ca. 10000 mites, P colonies were surviving with infestations of ca. 4000 mites. Several characteristics of the P bees contributed to suppressing the number of mites parasitizing their colonies

Summary — New discriminant analysis procedures have been presented to identify Africanized and European honey bees. These procedures are founded on data from 2 103 samples of honey bees collected from colonies at several locations in the western hemisphere and Kangaroo Island, Australia. Various univariate and multivariate analyses have been used to select the morphological characteristics and the groups of characteristics to be used in the analysis. The multivariate discriminant analysis correctly identified 565 (95.6%) of the 591 Africanized colonies and correctly identified all of the 1 512 European colonies.

A population genetic analysis of honey bees of the Mexican neotropical Yucatan peninsula shows that the range expansion of Africanized bees there has involved extensive introgressive hybridization with European bees. Yucatan honey bee populations now include many colonies with intermediate morphologies. Genotypes of mitochondria have disassociated from historically correlated Africanized or European morphology, producing diverse phenotypic associations. This suggests that the size of resident European populations may be important in explaining previously reported asymmetrical hybridization. Evidence of natural hybridization is encouraging for the use of genetic management to mitigate the effects of Africanized bees in the United States.