Effect of Cloake Board and 24 hour methods on royal jelly production and their effect on apiary economy

Introduction: Royal jelly is a secretion of mandibular and hyppopharyngial glands of young (ages 4-15) worker honey bees that is used to feed larvae in the first three days of their lives and queen during its entire life (Bogdanov 2012). Today, production of royal jelly and its usage by human is increasing as well as improving methods of production. China is the greatest producer of royal jelly, because they use high royal jelly producing lines and specific equipment and experienced beekeepers in the process (Krell 1996; Chen et al. 2002). No data is existing about the amount of royal jelly production in Iran, otherwise its consumption is increasing. Naturally, it is possible to harvest royal jelly from natural queen cells in swarming period of colonies, but at this way the amount of harvested royal jelly is very low. Colack Board and 24 hour methods are the most common methods for yielding bee queen in Iran, but their usage in royal jelly production have not been yet examined. So, this experiment was conducted in order to survey and compare these two methods of royal jelly production and determine the effect of this method on the acceptance of grafted cells and the amount of royal jelly harvested from each grafted cell and hive. In the second stage, honey productions of control colonies compared with experimental colonies and economic analysis of royal jelly production with these two methods are presented.
Material and methods: This experiment was carried out in honey bee colonies (Apis mellifera meda) of East Azarbaijan province in 2016. We used 30 honey bee colonies headed by one year old sister queens and the same contents of the hive and then, they were randomly divided into three groups. Experimental design was 2×3 factorial based on CRD, which had two factors including method and period. Ten colonies were organized as 24 hour protocol, 10 as cloack board method, and 10 untreated colonies as control. For this reason, 45 grafted cells were added into each hive. Experiment was repeated three times in May, June, and July. Royal jelly was gathered in the 3^rd day after grafting. Number of accepted cells was counted and the amount of royal jelly production from each cell was measured. as Also, the total amount of royal jelly production by each hive was calculated. Linear multiple trait model was used to analyze data. Statistical model was: Y_ij= μ + M_i + S_j + MS_ij + e_ij; where: Y_ij = record of each trait, μ = overall mean, M_i = effect of method, S_j = effect of month, MS_ij = interaction effect of method and month, e_ij = experimental error. The cost-income of the royal jelly production was calculated for the test colonies, considering the price of each kilogram of honey and jelly, 200 thousand Rials and 50 million Rials, respectively.  
Results and discussion: Results showed that there was no significant difference between two methods in acceptation rate of grafted larvae. The interaction between two factors (working method and time) was not also significant. But, there was a significant difference between the months in acceptation rate; so that, mean comparisons showed the lowest larvae acceptance in July (%78.7200) and the highest in June (%85.2700). No significant difference was observed between two methods based on total royal jelly production from each hive. Also, the interaction between two factors (working method and time) was not significant. However, the effect of time was significant; so that, the maximum amount of royal jelly production from each hive was occurred in May (9.7730 g/hive) and the minimum in July (8.3295 g/hive). The amount of royal jelly production from each cell in different amounts was not significantly different. Also, the effect of method and amount interaction was not significantly different. But amount of royal jelly harvested from each cell significantly affected by method; so, the amount of royal jelly per cell in cloack board method was more than 24 hours method (262.66 and 236.87 mg/cell, respectively). Cost-Income calculation showed that, by production of royal jelly, we can add 919.5 thousand Rials to the income from each hive. 
Considering the results of this study and other related reports (Sahinler 2005; Le Jiang 2001; and Elmi 2016), month and season had a considerable effect on royal jelly production. Colony internal contents (brood and food area and population) and external condition (honey and pollen flow) are varying with season (Buchler et al. 2013). Larvae acceptance and the amount of royal jelly could be affected by each of these factors. Larvae acceptance in this study was higher than other related reports (Kumar and Kumar 1999). Mean of royal jelly per hive in current research was lower than that of other report (Elmi 2016). It seems that environmental factors affected this trait. Due to climate situations followed by poor nutritional pollens in the nature, there was a decline in breeding quality of queens at the year of experiment. Mean of royal jelly production per cell was nearly the same as other related reports (Elmi 2016; Bogdanov 2012). Considering amount of royal jelly per cell, it seems that Cloack Board method is preferable to the 24-hour method. One of the advantages of the Royal jelly production on the experimental colonies was that none of the colonies had swarmed. Also, there was no significant difference between groups in honey production of three groups, and royal jelly production had not negative effect on the amount of honey production. Therefore, royal jelly production can be achieved by beekeepers to increase their income.
Conclusions: Generally, the results of this study showed that the percentage of larvae acceptance and the amount of royal jelly produced from each hive are acceptable in both ways. The amount of the royal jelly produced from each cell in the Cloack Board method is greater than the 24 - hour procedure, and the use of the Cloack Board method to produce royal jelly can be more advisable under the 24 h method, because: the amount of royal jelly are obtained from each cell is high and there is no need for the removal of the queen and the colony develops normally. Furthermore, production of royal jelly would increase the beekeepers income by using any of the above methods without any negative effect on honey yield, and it has a positive effect on swarming tendency of colonies.