Effect of Pollen Contaminated with Some Heavy Metals and Amitraz on the Physiological Conditions of Honeybee Workers Apis mellifera L. (Hymenoptera: Apidae)

Pollen grains are virtually the main source of protein, fats, vitamins and minerals in the diet of the honeybee, necessary for normal growth and development. The present study is concerned with the effect of pollen contaminated with the heavy metals cadmium, chromium and the acaricide Amitraz on the hypopharyngeal glands development, growth (changes in the dry weight of thorax ) and worker longevity. The obtained results showed that feeding the newly emerged workers on the control candy patty (candy + 10 % pollen) for 10 days promoted the hypopharyngeal glands development and the mean dry weight of thorax to the highest level compared with those bees fed on candy patty contaminated with various concentrations of both cadmium and chromium (0.5, 1, 3, 5, and 10 ppm). Statistical analysis showed that, no significant differences were found between the experimental diets, except chromium at the 10 ppm concentration which significantly decreased the hypopharyngeal glands development and the mean dry weight of thorax .Concerning the longevity of workers fed on the experimental diets contaminated with chromium and cadmium, the statistical analysis showed no significant differences between all the tested diets. With regard to the effect of the acaricide (Amitraz) on bees fed on diets contaminated with any concentration of (0.05, 0.1, .05, 1.5 and 3 ppm.). all of these concentrations failed in promoting the development of the hypopharyngeal glands. For, the mean dry weight of thorax and the longevity of workers fed on Amitraz, the statistical analysis showed no significant differences were found between the experimental dites.