A Combination Method of CO₂-Narcosis and Cold Treatment for Breaking Diapause of Bombus ignitus and Bombus terrestris Bumblebee Queens

Abstract

Bumblebees are important pollinators of crops and wildflowers. Bumblebees generally produce one generation per year. One of the key stages for year-round rearing of bumblebees is breaking diapause. To evaluate the effects of a combination method of CO 2 -narcosis and cold treatment to break the diapause of B. ignitus and B. terrestris queens, we determined whether this method affected their ability to establish a colony after the diapause break. The diapause treatment regimes that were utilized were CO 2 (CO 2 -narcosis), CT-1M (cold treatment at 5°C for 1 mo), CT-1M-CO 2 (CO 2 -narcosis after cold treatment for 1 mo), CT-2M-CO 2 (CO 2 -narcosis after cold treatment for 2 mo), CT-2M (cold treatment for 2 mo), CT-2.5M-CO 2 (CO 2 -narcosis after cold treatment for 2.5 mo) and CT-2.5M (cold treatment at 5°C for 2.5 mo). In view of the effects on the colony developmental characteristics of B. ignitus queens, the most favorable diapause treatment was CT-1M-CO 2 . A combination method of CO 2 -narcosis and cold temperature treatment yielded better results than that of single CO 2 -narcosis or cold temperature treatment on the colony development of diapause-broken B. ignitus queens. In the case of B. terrestris queens, we concluded that a combination method of CO 2 and cold temperature treatment yielded better results than that of a single cold-temperature (up to 2 mo) treatment. In conclusion, the findings of the present study indicated that the combined application of CO 2 and cold temperature was a favorable method for the colony development of diapause-broken B. ignitus and B. terrestris queens compared with only CO 2 -narcosis or cold temperature treatments. A combination method of CO 2 and cold treatment reduced the side effect of CO 2 -narcosis and shortened the duration of cold treatment by at least 1 mo. AbstractInt.

Effects of neonicotinoid imidacloprid exposure on bumble bee (Hymenoptera: Apidae) queen survival and nest initiation

“…The company ensured that all queens were of similar age and were in diapause for 5-7 months at the time of purchase. Carbon dioxide narcosis and cold treatments have been shown to shorten time to initial oviposition and increase oviposition rate after diapause in B. ignites and B. terrestris (Yoon et al 2014). Therefore, to break diapause, queens were treated with carbon dioxide (99%) for 2 min then kept in cold storage (2°C) overnight.…”

It is buzziness time: rearing, mating, and overwintering Bombus vosnesenskii (Hymenoptera: Apidae)

“…Survival in cold storage has been found to decrease drastically after 3 months ( Lindsay 2020 ), which is relatively short compared to the length of time mated gynes undergo overwintering in the wild ( Rowe et al 2023 ). Initial body mass has been found to impact overwintering survival, with heavier queens having an advantage due to an increase in the accumulation of lipids in the bumble bee’s fat body ( Alford 1969 , Holm 1972 , Haunerland and Shirk 1995 , Beekman et al 1998 , Fliszkiewicz and Wilkaniec 2007 , Yoon et al 2010 , Lindsay 2020 ). We documented high success rates when overwintering gynes for 54 days, as 59.1% of low-elevation gynes and 91.9% of high-elevation gynes survived.…”

Evaluation of Reference Genes for Real-Time Quantitative PCR Analysis in Tissues from Bumble Bees (Bombus Terrestris) of Different Lines

“…The five different lines of B. terrestris virgin queens used in this study were kept in the National Institute of Agricultural Science RDA's insect pollinator laboratory in Wanjangu, Jeonju, Korea (35 • 44 43 N, 128 • 02 22 E). From the artificial breeding system [23,24], queen virgin bees were collected from five different lines in spring (2022), line 1, line 2, line 3, line 4, and line 5, and each queen bee was selected within 24 h of emergence. Each line was selected in the direction of a high colony formation rate and worker bee productivity and was selected as a line that had maintained the genetic traits of 10 generations or more.…”