Genetic diversity of four populations of honey bee, Apis mellifera from two vegetation zones in Nigeria namely; southwest rainforest and northcentral derived savanna was analysed using fifteen morphometric characters and five microsatellite loci. Discriminant function analysis (DFA) of the morphometric data revealed a considerable variation of morphological characters between the sampled localities while Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA) produced overlapping clusters of the populations sampled indicating lack of separation between the various populations. The genetic diversity (FST) revealed low differentiation among populations suggesting that geographic distance was not an impediment to gene flow among populations. The overall FIT value indicated that the four populations have a deficiency of heterozygotes suggesting the presence of inbreeding within populations. The analysis of molecular variance (AMOVA) showed that 91% of the total molecular variance existed within the populations while 9% existed among populations, indicating low inter population genetic variation. It is suggested that there is an apparent loss of genetic diversity in the populations of A. mellifera studied in the two vegetation zones of Nigeria. This could have implication for the health and stability of these bee populations.
Key words: Biodiversity, genetic diversity, honey bees, morphometry, microsatellite, population genetics.