Research on allozymes have revealed enormous genetic variability and indicated a positive association between heterozygosity and fitness. These parameters are also associated with metabolism as well environmental conditions. During a study to determine the genetic variation we have observed very high heterozygosity in Pgm locus. When we attempted to reproduce the results in order to search for the cause of this high level of heterozygosity, we could not succed in our first attempt. Therefore we have taken several samples at different times and we have noticed that there is a seasonal change in heterozygosity level at Pgm locus. Here, we aim to report the seasonal change that occur in the heterozygosity level of Pgm enzyme. Winter bees appear to have high heterozygosity for PGM, whereas summer bees are at HWE for PGM genotypes.