INFLUENCE OF USING A POLLEN REPLACER ON THE BEE FAMILY DEVELOPMENT

Abstract

SUMMARY The pollen replacers used as supplementary source o f dietary protein for the bees during wintering and their effect on the maintenance and d evelopment of the bee families is a common objective of the beekeepers (M alaiu A., 2005). We tested a pollen replacer made of soybean meal, dry brewer yeasts, skimmed powder milk, in a watery environment with extraction ratio 4/1. After 24 h, the supernatant w as lyophilised and a fine yellowish power with a specific smell was obtained. The biological material was represented by bee families of Carpatina Foti breed, the field variety. The control group consis ted of 4 bee families of similar breed and variety, with the same population al area spread over 7 frame intervals, weighing in average 1.85 kg, with similar reserves of 1.85 kg honey and 2 kg of pollen and virgin wax, but without supplementary feed. In the experimental group, the pollen replacer was given as cakes during winter (October 25 through February 1). The effects of this pollen replacer on the speed of growth of the young bees a nd on the development of the hypopharyngeal glands that produce the royal jelly in the worker bees, were monitored. It was observed that the supplementary feeding with pollen replacer did not influence significantly the size of the population when the w inter was over, an average physiological decrease of 27% being observed in both groups (M arghita � , L.A., 2002). In the experimental group, the consumption of 65% of the pollen replace r cakes resulted in an intense growth of the young bees (the area occupied by the young bees was 30 dm 2 , compared to 12 dm≤ in the control group) and a uniform arrangement in the hon eycomb, as concentric rings of freshly laid eggs, of young larvae and enclosed young bees. The hypopharyngeal glands were investigated by optical microscope, 10 samples from each nucleus, after fresh preparations were placed between the microscope mount and slide. It was observed that the hypopharyngeal glands harvested on Fabruary 1 st from the worker bees of the experimental group had progressed through all four stages, their acini being fully developed and the cisterne having a mat consistency. The hypopharyngeal glands of the worker bees from the control group had the characteristics of the stage 3 of development, with the acini nuclei located in the centre of the cells, which shows tha t their activity started later than in the experimental group.