BIOLOGY OF HONEYBEE (APIS MELLIFERA L.) SPERMATOZOA. 1. Effect of different diluents on motility and survival

Abstract

SUMMARY Honeybee semen was stored in different diluents at 14 °C for 9 months. Fine disposable sterile ca-pillary tubes of 0.1 cm diameter were used for semen storage. Sperm motility was assessed at regular in-tervals and queens were inseminated with freshly diluted and 60-90 days old semen samples. Tris buffer diluent (pH : 7.19) containing concentration of K ! and Na as found in the spermatheca of the queen bee acted as a reversible inhibitor of sperm motility, even after 9 months of storage. This support our pre-vious hypothesis af an ionic basis for the control of sperm motility and longevity. The significance of various other diluents used for the preservation of semen of other domestic ani-mals, with regard to in vitro survival of honeybee spermatozoa is discussed. Spermatozoa survived lon-ger in tris buffer diluent at pH : 7.19 than at pH : 8.4. Tris buffer diluent with cations and Varhom diluent 11 with catalase can possibly be used for increa-sing the volume of the freshly ejaculated semen, particularly when single drone inseminations are required for genetic studies. However, when the queens were inseminated with 60-90 days old semen samples, less than half million spermatozoa reached spermatheca. The development of a diluent for the prolonged storage of honeybee semen seems much more complicated than for the other domestic animals, because in the former case millions of spermatozoa should remain viable in the spermatheca for 3 or more years.