• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.120-122
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• 2003

It was investigated whether developmental characteristic of foundation queens of Bombus ignitus collected in the 11 localities including Jeongsun have any effects by the first oviposition days. Materials and Methods: materials - insect : foundation queens of Bombus ignitus collected in the 11 localities. Methods - we investigated the rate of colony foundation, progeny-queen production and the number of adults emergence for the relationship between first oviposition day and colony development of B. ignitus (omitted)

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.151-154
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• 2003

The effect of photoperiodic regimes on the oviposition and colony development of Bombus ignitus queens was examined with 0L, 8L, and 16L under $27^{\circ}C$ and 65% R. H. Among these photoperiod regimes, the oviposition rate at 8L and 16L was 80.2% and 83.1%, respectively, which was 12-15% higher than that at the dark condition (0L). Duration up to first oviposition at 8L and 16L was 17.5 days and 16.5 days, respectively, which was 2-3 days shorter than that at 0L. The colony foundation rate at 8L and 16L was 9.2% and 10.4%, respectively, which corresponded to 1.7-2.0-fold higher than the value at 0L. In addition, the rate of progeny-queen production at 8L and 16L was also two fold higher than that at 0L. Taken these together, the light conditions (8L and 16L) rather than dark condition (0L) were more suitable for oviposition and colony development for B. ignitus in the indoor rearing condition.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.117-121
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• 2004

Chilling temperature and colony development in Korean native bumblebee, Bombus ignitus and introduced B. terrestris were firstly investigated. Among four chilling temperatures of -2.5, 0, 2.5 and 5$^{\circ}C$, 2.5$^{\circ}C$ showed the best result at the survival rate after artificial hibernation in both species. The survival rate after chilling was somewhat higher in B. ignitus until three months of cold treatment, but it was higher in B. terrestris at four months of cold treatment. In colony development of queens broken diapause by CO$_2$ treatment, oviposition rate and preoviposition period of B. ignitus were 72.5％ and 17.4 days, respectively. These values were 6.1％ higher and 7.4 days shorter than those of B. terrestris. The period up to colony foundation, the first male and queen emergence of B. ignitus were 62.8,66.4 and 63.0 days, respectively, and these values were 2.1-29.5 days shorter than those of B. terrestris. But, the duration up to first worker emergence of B. ignitus and B. terrexrris did not differ as 28.6 and 28.4 days, respectively. On the other hand, the rate of colony foundation and progeny-queen production of B. terrestris, which are the important indication in evaluating the quality of colony, were 14.2 and 13.5％, respectively and these values are 3.8 to 5.7 fold higher than those of B. ignitus. Besides, the numbers of progenies of B. terrestris reached 104.2 workers, 317.9 males and 21.1 queens, which corresponded to 1.1-1.8 fold those at B. ignitus. Therefore, above results showed that colony development of B. terrestris is superior to that of B. ignitus.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.139-144
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• 2003

The effect of $CO_2$-treatment on interrupting diapause of Bombus ignitus was examined to provide a means for year-round rearing of the bumblebee. When mated young queens were exposed to 65% or 99% $CO_2$ for 30 min daily during two consecutive days, oviposition rate increased to 75% and 77%, respectively, comparing 50% in $CO_2$-untreated queens. At the same time, the days needed to first oviposition shortened to 17-18 days in $CO_2$-treated queens, comparing to 30 days in $CO_2$-untreated queens. $CO_2$-treatment at the second day after mating was appropriate to the oviposition and colony development. $CO_2$-treatment showed a positive effect on the oviposition and colony development, but less than them of overwintered queen in numbers of produced progeny. It can be concluded that $CO_2$-treatment to B. ignitus is insufficient to produce commercial grade bumblebee colony in spite of its capability for promoting oviposition, because the treatment failed to form a big colony.

• 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.