Nosema ceranae and queen age influence the reproduction and productivity of the honey bee colony

Abstract

The strength of the honey bee colony and the quality concerning brood production, number of worker bees and honey yield depend substantially upon the characteristics of the queen. Reproductive and productive capacities of the colony, as two important physiological qualities can depend a great deal on the age of the queen. Over the years, the laying ratio of queens could decrease depending on the age; therefore colonies headed by one-year-old queens have proven to be more efficient considering colony population and honey production than ones with older queens. Nosema ceranae infection is a possible reason for the decrease in reproductive capacities and the reduction in the honey production of infected colonies. With the help of numerous pheromones, the queen can preserve colony homeostasis, however exhausted by N. ceranae infection she might compromise the renewal of worker population. The aim of this research is to investigate the influence of N. c-eranae on reproduction and productivity of honey bee colonies headed by queens of different age. Experiment was conducted on 27 honey bee colonies equalized with regard to brood, food source, number of worker bees and Nosema infection. In the three year investigation period (2009-2012), Nosema detection, identification and spore load per each colony, as well as parameters of colony reproduction (such as uncapped and capped brood area, queen egg-laying rate and colony strength) and productivity (the total extracted honey and the winter honey stores) were recorded. Concerning the influence of the age of the queens on followed parameters we compared one, two and three-years old queens and found significantly higher reproductive and productive values in favour of younger ones. Significant differences regarding the effects of N. ceranae infection on productive and reproductive characteristics could be explained with a higher capacity of one year old queens to compensate the effects of Nosema infection; a capacity which gradually declines in the second and the third year.