A fulllength cDNA encoding β1tubulin from the parthenogenetic rice water weevil (RWW), Lissorhoptrus oryzophilus in China and from the sexual RWW in the United States was cloned by RACE and RTPCR, respectively. The full cDNA sequence was 1727 bp for the parthenogenetic RWW, and 1730 bp for the sexual RWW. Both cDNA sequences contained a 1344 bp open reading frame encoding 447 amino acid residues. The putative molecular weight of these amino acid residues was approximately 50 kD at an isoelectric point of 4.54. The cloned β1tubulin amino acids shared a high similarity (95% to 100%) with the βtubulin homologues from other insects. Absolute quantification revealed that the β1tubulin was expressed at a significantly higher level in the ovary of the parthenogenetic RWW (3.14×107 copies/μL±0.66×107 copies/μL) than the sexual RWW (5.08×106copies/μL±0.47×106 copies/μL). It is suggested that the differential expression of β1tubulin in the parthenogenetic RWW may play an important role in the formation of the mitotic spindle.