• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.1
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• pp.19-24
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• 2010

Bumblebees are widely used to pollinate crops in greenhouses and fields. Here, we investigated whether different wake-up treatments during a short period of 1~3 days just before indoor rearing has any effects on oviposition and colony development of $CO_2$-treated Bombus ignitus queens and artificially hibernated B. terrestris queens The wake-up regimes were defined as 16L for 1 day (16L-1), 16 L per day for 3 days (16L-3), 24L for 1 day (24L-1), or 24D for 1 day (24D-1). Among these wake-up treatments, the oviposition rate and preoviposition period of B. ignitus queens reared at 24L-1 were 16.7~25.1% higher and 1.0~3.5 days shorter than other wake-up treatments. B. terrestris queens reared at 24L-1 also showed the best results for egg-laying characteristics, which were 8.9~18.8% higher for oviposition and 0.6~3.5 days shorter for preovipostion period than other wake-up treatments. Furthermore, B. terrestris queens reared at 24L-1 were 17.5% and 13.8% higher in rate of colony foundation and queen production, respectively, than other wake-up treatments. These results show that the most favorable wake-up treatment just before rearing for egg-laying and colony developmental characteristics of B. ignitus and B. terrestris queens was 24L-1. Overall, our findings indicate that a wake-up treatment just before rearing was effective for colony initiation and colony development of bumblebee queens.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.167-174
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• 2011

The large bumblebee $Bombus$ $terrestris$, indigenous to Europe and adjacent areas and used extensively for high-value crop pollination, has been artificially introduced to several parts of the world. Here we show the occurrence of interspecific hybridization between the bumblebee species $B.$ $hypocrita$ $sapporoensia$ and $B.$ $terrestris$ under laboratory conditions. The mating and oviposition percentages resulting from the interspecific hybridization of a $B.$ $terrestris$ queen with a $B.$ $h.$ $sapporoensis$ male were higher than those resulting from the intraspecific mating of $B.$ $h.$ $sapporoensis$. Furthermore, a competitive copulation experiment indicated that the mating of $B.$ $h.$ $sapporoensis$ males with $B.$ $terrestris$ queens was 1.2-fold more frequent than the mating of these males with $B.$ $h.$ $sapporoensis$ queens. The interspecific hybridization of a $B.$ $terrestris$ queen with a $B.$ $h.$ $sapporoensis$ male produced either $B.$ $terrestris$ workers or the $B.$ $terrestris$ male phenotype, and the hybridization of a $B.$ $h.$ $sapporoensis$ queen with a $B.$ $terrestris$ male produced $B.$ $h.$ $sapporoensis$ males. Our results indicated that interspecific hybridization occurred between $B.$ $h.$ $sapporoensis$ and $B.$ $terrestris$. These results suggest that such hybridization will have a negative competitive impact and will cause genetic contamination of native bumblebees.

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.1
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• pp.7-13
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• 2008

We investigated mating conditions about care temperature of queen before mating, mating period, and number of queen per mating cage to improve mating rate of Bombus terrestris. Among $19^{\circ}C$, $22^{\circ}C$ and $25^{\circ}C$, care temperatures of queen before mating, queen cared at $19^{\circ}C$ was more effective than those at $22^{\circ}C$ and $25^{\circ}C$ in death rate during care and mating periods, and colony development In case of mating period, oviposition rate and preoviposition periods at queen mated during 3 days were 89.3% and 11.4 days, respectively, which was higher and earlier than those of queen mated during 5 days and 7 days. The rate of worker emergence, colony foundation and progeny-queen production at 3 days-mated queen were also 2.0-11.6% higher than those at queen mated during 5 days and 7 days. In number of queen per mating cage, the rate of worker emergence, colony foundation and progeny-queen production queen mated at mating cage with 10 queens and 30 males were 41.5%, 25.9% and 23.2%, respectively. These values correspond to 1.5-6.8 folds those queen mated at cage with 20 queens and 30 queens. Therefore, we supposed that care temperature favorable for B. terrestris queen was $19^{\circ}C$ and the period need to mating was 3 days, and the number of queen per mating cage ($55{\times}45{\times}65\;cm$) was 10.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.2
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• pp.51-57
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• 2014

Bumblebees are important pollinators of crops and wildflowers. The Korean native bumblebee, Bombus ignitus, undergoes one generation per year, and induction of artificial hibernation is essential for year-round rearing of the bumblebee. Keeping queens under cold treatment conditions for several mo is an effective method for terminating their diapause and promoting colony development. In the present study, we investigated how the timing and duration of chilling affect the artificial hibernation of B. ignitus queens. In the timing assessment, cold treatment was instituted at 12 d, 40 d, or 100 d after eclosion under a constant temperature of $5^{\circ}C$ and 80% humidity. The queens that entered cold treatment at 12 d after emergence evidenced the highest survival rates: 86.7% at two mo, 73.3% at three mo, and 46.4% at 4 mo. Survival rates were reduced under storage conditions at 12 d, 40 d, and 100 d after emergence. When queens were subjected to chilling at 8 d, 12 d, or 16 d after eclosion with constant 80% humidity, the queens stored at 12 d after eclosion exhibited the highest survival rates, which were 84.6 at one mo, 25.0% at two mo, and 7.9% at three mo. In regards to the duration of the cold period, the queens that hibernated for at least two mo evidenced optimal colony development rates. The rates of oviposition, colony foundation, and progeny-queen production of queens hibernated for two mo were 60.0%, 30.0%, and 13.3%, respectively. These values were 6.0 to 13.3 times higher than those in the queens that hibernated for 15 d. Therefore, a cold period of at least 2 mo applied 12 d after emergence were found to be the most favorable conditions for diapause break in B. ignitus queens.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.93-98
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• 2010

Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. An artificial hibernation is essential for year-round rearing of the bumblebee, which passes through one generation per year. Here, we investigated whether a chilling temperature and humidity affect artificial hibernation of the bumblebee queen Bombus terrestris. In chilling temperature regimes of $0^{\circ}C$, $2.5^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ or $12.5^{\circ}C$ under constant humidity >70%, the queens stored at $2.5^{\circ}C$ exhibited the highest rate of survival, which was 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months, and 24.0% at 6 months. Rates of survival decreased at the following temperatures: $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. Colony developmental characteristics after diapause were 1.2- to 1.5-fold higher than those of queens stored at $5^{\circ}C$. In terms of chilling humidity, the queens hibernated at 70% under $2.5^{\circ}C$ exhibited the highest rate of survival, which was $93.3{\pm}3.4%$ at one month, $83.3{\pm}0.0%$ at two months, $76.7{\pm}0.0%$ at 3 months and $36.7{\pm}12.1%$ at 5 months. The rates of oviposition, colony foundation and progeny-queen production of queens hibernated at 70% were 80.8%, 30.8% and 30.8%, respectively. These values correspond to 1.7- to 3.3-fold increases in comparison to queens stored at 50% humidity. Therefore, $2.5^{\circ}C$ and 70% R.H. were the favorable chilling temperature and humidity conditions for diapause break of B. terrestris queens.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.393-401
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• 2009

About 50,000 hives of Bombus terrestris are used for pollination of tomato and other economical crops (fruit vegetables and fruit trees) in Korea. Therefore this study was conducted to find out the effective use of B. terrestris and its economic effect in the major beefsteak-tomato cultivation areas from February to August in 2008. The pollinating activities, rate of bite-mark and lifespan of B. terrestris's hive according to all beefsteak-tomato varieties (Super Momotaro, Zeus42, Mascara and Super Sunroad, 500 $m^2$, $9,600{\sim}12,000$plants) were apparent by regular supplement of pollen ($5{\sim}6g$/3 days) to the hive of B. terrestris. Especially, Super Momotaro and Super Sunroad variety were most distinctive in the effects by regular pollen supplement.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.270-274
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• 2013

The bumblebee, Bombus terrestris, has played an important role as one of the alternative pollinators since the outbreak of honeybee collapse disorder. Recently, pathogens and parasites such as viruses, bacteria and mites, which affect the life span and fecundity of their host, have been discovered in B. terristris. In order to detect the microsporidian pathogen, Nosema spp. in the field populations of B. terristris, we collected adults and isolated their genomic DNA for diagnostic PCR. The PCR primers specific for Nosema spp. were newly designed and applied to gene amplification for cloning. Only small subunit ribosomal RNA (SSU rRNA) gene of N. ceranae was successfully amplified among examined genes and sequenced, which indicates that N. ceranae mainly infects the examined field population of B. terristris. To detect of SSU rRNA gene, two regions of SSU rRNA gene were selected by primary PCR analysis and further analyzed in quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis demonstrated that SSU rRNA of N. ceranae was detected at concentration as low as $0.85ng/{\mu}l$ genomic DNA. This result suggests that the detection via qRT-PCR can be applied for the rapid and sensitive diagnosis of N. ceranae infection in the field population as well as risk assessment of B. terristris.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.329-337
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• 2018

To increase the mating rate of Bombus ignitus used as insect pollinator, we investigated the sexual maturity time of B. ignitus. In investigating ovary development such as the number of eggs per ovariole and spermatheca size, the time of sexual maturity of queen was 10 days after eclosion. In case of male, the number of sperm was 246 thousand at immediately after eclosion, and was highest as 480 thousand at 9 days, and tended to show a dramatic decline at 35 days (87 thousand). The more mating time, the less the number of sperm. In consideration of number of sperms, the time of sexual maturity of male was 3-15 days after eclosion. In the sexual maturity time of queen in mating, the queen was not mated at immediately after eclosion, and showed a decrease in 20 days. In terms of the rate of mating and oviposition, the favorable time for mating of queen was 9-20 days. On the other hand, the male showed 3.3% of mating at immediately after ecolosion, showed the highest of 43.3% at 6 days after eclosion, and tended to decrease in 25 days. The sexual maturity time for mating of male was 6-20 days. In summary, our results indicate that sexual maturity time of B. ignitus in reproductive organs and mating is most favorable in 9-12 days after eclosion for queen and 6-9 days for male.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.05a
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• pp.128-128
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• 2001

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.164-164
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• 2004