Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 2000
Publication Date: N/A
Interpretive Summary: Honey bees are very unusual in that the sperm that are stored in a special organ in the queen's body survive for many years, even in the warm temperatures of the hive. There is a well developed technique to artificially inseminate honey bee queens, but the semen is generally held for not longer than one week at room temperature. If we could store honey bee semen for longer periods of time, it would enhance our ability to improve our strains of bees and allow for the exchange of genetic types without worry about parasites and diseases. This study showed that honey bee semen was very durable when stored in sealed fine glass tubing, and could be kept at least as long as 6 months at room temperature or a cooler temperature aboving freezing. This durability of the semen should allow breeders to keep semen for use well beyond the normal spring period when drones are plentiful, or to ship semen to other breeders to increase the genetic variability in a local breeding population.
Technical Abstract: The development of practical techniques for the storage of honey bee (Apis mellifera L.) semen would significantly improve our ability to breed for desirable genotypes and maintain genetic diversity in populations. Artificial insemination of queens has been possible for some time, but the semen used is usually freshly collected, or held for less than a week at room temperature. I wished to examine the limitations of spermatozoal survival at non-frozen temperatures. Pooled diluted semen was stored in sealed capillary tubes at room temperature (25 celsius) or in a refrigerator set to 12 celsius, for periods up to one year. Survival of spermatozoa was assayed by a dual fluorescent staining technique using SYBR-14 and propidium iodide stains, which readily distinguishes live and dead cells. No significant loss of viable spermatozoa accured within the first 6 weeks. Between weeks 6 and week 9, the percent live spermatozoa fell from 80% to 58% and remained at that level until after 39 weeks. By week 52, samples at room temperature, but not at 12 celsius, fell to 18.9% live spermatozoa. Non-frozen storage of honey bee semen has potential for short-term preservation of germplasm, however several factors need to be studied further to optimize survival rates.