[ ]-Narcosis Time Favorable for Colony Development in the Bumblebee Queen, Bombus terrestris

As a means for year-round rearing of bumblebee, CO$_{2}$ -narcosis time favorable for colony development was identified in Bombus terrestris. CO$_{2}$ -narcosis time divided into five classes: 11 days of adult emergence (A-11), the day of adult emergence (A-0), late pupal stage (LP), middle pupal sta ge (MP), and early pupal stage (EP). In egg-laying characteristics, the oviposition rate of LP, A-11 and A-0 was over 76.0$\%$, but that of MP and EP was less than 61.1 $\%$. At the same time, the days needed to first oviposition shortened to 9.8 ­10.5 days in A-11, A-O and LP, comparing to 13.7 -16.1 days in MP and EP. The rate of colony foundation, progeny-queen produced and period of colony foundation of A-11 were the best results in among those at different CO$_{2}$-treatment time. The number of worker produced was 109.2 -110.5 in A-H, LP and A-H, comparing to 82.0 - 86.8 in MP and EP. Also, the number of progeny-queen produced of A-H, A-O and LP was 36.1, 41.0 and 71.3, respectively, which corresponded to 1.5 - 3.1 fold higher than MP and EP. Taken these together, CO$_{2}$-narcosis time favorable for colony development was determined to be 11 days of adult emergence. Also, the day of adult emergence and late pupal stage showed a positive effect on the oviposition and colony development in CO$_{2}$-narcosis time.