Submitted to: Cryobiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2005
Publication Date: 2/20/2006
Citation: Collins, A.M., Mazur, P. 2006. Chill sensitivity of honey bee, apis mellifera, embryos. Cryobiology. 53:22-27. Interpretive Summary: The beekeeping industry is suffering from increasing production costs due to two parasitic mites and an antibiotic resistant disease. The long term solution is to breed more resistant bees. To enhance breeding success, a system is needed to keep the genetic diversity of the breeding population high and to maintain desirable stocks. Recent success with freezing fruit fly eggs in liquid nitrogen holds promise that a similar technique could be used to preserve honey bee eggs as well. These eggs can then be revived and used to produce queen and male bees for breeding. Our research showed that honey bee eggs that were 40 to 62 hours old had better survival when exposed to freezing temperatures than did eggs 24 hours old. These results will be used to develop a freezing technique for honey bee eggs. This information will be used by scientists and beekeepers involved in the production of honey bee queens.
Technical Abstract: Improved methods for preservation of honey bee, Apis mellifera L., germplasm would be welcome to beekeeping industry queen breeders. The introduction of two parasites and the emergence of an antibiotic resistant disease have increased demands for resistant stock. Techniques for artificial insemination of queens are available, and semen has been cryopreserved with limit success. However, cryopreservation of embryos for rearing queens would complement current practices and has the additional benefit of providing drones of the same type. Protocols for the cryopreservation of Drosophila embryos were optimized by using embryos of the most chill tolerant age. To determine this age for the honey bee, synchronized cohorts of eggs (24 h, 48 h or 62 h embryos) from caged queens were exposed to 0 deg C, -6.6 deg C, or -15 deg C for various times, and successful hatch measured. In a second experiment, 40 h, 44 h and 48 h embryos were exposed to -6.6 deg C. Twenty-four hour embryos were significantly more likely to die from the chilling than the older ones, which were not significantly different. The 48 h honey bee developmental stage corresponded to the stage of a 15 h Drosophila, which was most chill tolerant. Future research on cryopreservation of honey bee embryos should use embryos of about 48 h.