Thesis (M.Sc.)--Chulalongkorn University, 2001

Dwarf honey bee (Apis florea Fabricius, 1787) is a native species of honey bee in Thailand. Genetic variation within dwarf honey bees sampled from various parts (the North, the North-East, the East, the central, and the South including Samui Island and Pha-Ngan Island) of Thailand were determined by PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) technique. Three mtDNA regions (inter CO I-CO II region, L-rRNA gene, and Cytb I-tRNASer gene) were amplified. The size of inter CO I-CO II region, L-rRNA gene, and Cytb I-tRNASer gene are 1590, 760, and 870 bp, respectively. A set of restriction enzymes (Acl I, Afl I, Ase I, BamH I, Bcl I, Dra I, EcoR I, Hind III, Hinf I, Rsa I, Ssp I, and Swa I) were used to analyse the variation. Six restriction enzymes; Ase I, Bcl I, Dra I, Hind III, Hinf I, and Ssp I could digest the PCR products of inter CO I-CO II region, and only three restriction enzymes; Ase I, Dra I, and Ssp I could be digested the PCR products of L-rRNA gene and Cytb I-tRNASer gene. No variation was found from PCR- RFLP analysis in L-rRNA gene and Cytb I-tRNASer gene among A. florea populations in Thailand (180 colonies). Two different haplotypes were found in the inter CO I-CO II region when digested the PCR products with Ase I. The different haplotype was deteced from a colony of A. florea in Prachub Kiri Khan (lower part of central Thailand). The size of PCR product in the inter CO I-CO II region of A. florea was smaller than A. mellifera and A. cerana. Thus the variation in this region of mtDNA of A. florea may be less with the deleted sequences. Furthermore, the basic biology of A. florea such as the seasonal migration, swarming, and absconding including the well adaptation of this species might be caused they can be survived in the environment and distributed very widely and rapidly. Thus low of mtDNA variation among them was detected.