The honey bee Apis mellifera workers used in the present study were from colonies headed with open mated local Carnica queens. The foraging activity of honeybee workers was monitored in a strong, moderate and weak colony from dawn and up to the hour of sunset in the four annual seasons. The highest peak of worker bee activity was between 11.00 - 11.30 am, 8.30 - 9.00 am, 8.00 - 8.30 am and 10.00 - 10.30 am in the winter, spring, summer and autumn season, respectively. However, in the spring and summer season there was a second peak in honeybee activity, but lower in magnitude, between 4.00 to 4.30 pm. In all cases the honeybee workers activity as affected to temperature was positive, as for light intensity it was observed that a certain light level was required to initiate the honeybee workers activity, but  not necessary when it was at its highest lux. Honeybee workers were gamma irradiated by 20, 50, 100, 150 or 200 rads. Under conditions of the current laboratory experiment, Isozyme system was estimated for identification in honey bee workers and as affected by gamma irradiation. The zymogen reveals that Malic dehyrogenase 1, (Mdh1) had the same degree of intensity in irradiated and non-irradiated honeybee workers. Band Mdh2 and Mdh 4 appeared to be affected in honeybee workers irradiated with 40 or 200 rads. Meanwhile, a unique band Mdh 0.5 was expressed only in honeybee workers irradiated with 20 rads.