Myeong Lyeol Lee

Prevalence of Nosema and Virus in Honey Bee (Apis mellifera L.) Colonies on Flowering Period of Acacia in Korea.

Honey production from approximately 1.6 million colonies owned by about 199,000 Korean beekeepers was almost 23,000 metric tons in 2009. Nosema causes significant losses in honey production and the virus decreases population size. We initiated a survey of honey bee colonies on the blooming period of Acacia to determine the prevalence of Nosema and virus in 2011. Most Korean beekeepers have moved from the south to north of Korea to get Acacia nectar for 2 mon. This provided a valuable opportunity to sample bees originating from diverse areas in one location. Twenty hives owned by 18 beekeepers were sampled in this year. Nosema spore counts ranged from zero to 1,710,000 spores per bee. The average number of nosema spores per bee was 580,000. Approximately 95% of the colonies were infected with Nosema, based on the presence of spores in the flowering period of Acacia. This indicates that Nosema is the predominant species affecting honeybee colonies. Also, the seven most important honeybee viruses were investigated by reverse transcription-PCR. Among them, four different viruses were detected in samples. Black queen cell virus was present in all samples. Chronic bee paralysis virus was detected in 10% of samples. Deformed wing virus was present in only 5% of the samples. Prevalence of Sacbrood virus was 15%. However, Cloudy wing virus, Israel acute paralysis virus and kashmir bee virus were not detected in any of samples.

Studies on the Proximate Components, Organic Compounds, Mineral Constituents and Vitamin C of Mandarin (Citrus unshiu) Honey Produced in Korea

In order to use as a new functional food material, we analyzed the chemical components including the proximate components, organic compounds, minerals and vitamin C of mandarin honey which were produced in South Korea. The condensed rate of methanol extraction in honey was 84.5% and main organic compounds that extract by organic solvents in GC-MS analysis were trichloromethane, methylolpropane, cyclopentane, acetoxyethane and so on. Also, main aromatic compounds that extract by organic solvents in SPME analysis were acrolein, acetic acid, chloracetonitrile, acrylaldehyde, silanamine, cycloheptatriene and many more. Proximate composition was water content 25.06%, crude protein 0.12%, crude fat 0.02%, crude ash 0.07% and carbohydrate 74.72%. This was higher than the crude protein (0.1%) and crude ash (0.06%) content of acacia honey, and lower than the crude protein (0.23%) and ash content (0.24%) of manuka honey tested as a control group. Free sugar that analyze by HPLC consisted of fructose 39.29%, glucose 31.67%, and total sugars was 70.96%. Vitamin C was not detected. Minerals by ICP analysis were detected total 16 kinds, Na 2.340ppm > Ca 1.751ppm > B 0.380ppm > Mg 0.365ppm > Fe 0.348ppm and so on. Especially, some minerals such as Ca, Mg, Zn, Fe, Cu, Si etc. contained in mandarin honey are good for human health.

Reproductive Performance of Laying Worker of Apis cerana in Queenless Colonies

The Asian cavity-nesting honey bee, Apis cerana, the workers ovaries is very active in queenless colonies. We investigated the duration of egg laying by laying workers, egg-laying behavior, determine egg load in ovaries, estimate oviposition rate nad number of eggs per cell in three queenless colonies of Korean A. cerana. The number of eggs laid by laying workers at different times on the manipulated comb was checked and counted. We observed that the laying workers spent, on average, 109.2 seconds per cell. During oviposition, the laying workers showed two types of behaviors, viz; a still phase, and a recovery phase. On average, 4.0 of worker eggs per cell per week was recorded. The workers laid three different shapes of eggs in a cell. The laying workers ovaries retained 1 to 4 mature eggs. This suggests that a laying worker may lay from one to four eggs per oviposition. We did not observe false-queen in Korean A. cerana in three queenless colonies. In this study, we reported for the first time that one worker cell of A. cerana retains up to 33 eggs in queenless condition. The queenless colonies build the comb and lay eggs in new comb, and also reared the new queen without successful development of the queen larva from laying worker eggs.

Biological Mitigation of Sacbrood Disease on Apis cerana Colonies

Apis cerana is native honey bee species in Korea. This honey bee species has well adapted to cold winter. Apis cerana honey is preferred by domestic consumers. However, this honey bee species has been declined by sacbrood disease. Sacbrood is caused by a virus. Until now there has not been any chemical to treat this disease except biological method and the selection of sacbrood resistant bee stocks. This research was conducted from June to August, 2014 at the A. cerana apiary of NAAS, Suwon, Republic of Korea. Sacbrood disease on A. cerana colonies was observed and biological method was applied to treat the disease. The results of our study showed that the rate of infected colonies was from 26.0% to 87.0%. By applying requeen measure, the rate of recovered colonies was 57.1%, while the method of caged queen got only 28.6%.