FERTILIZATION BY MICROINJECTION OF CRYOPRESERVED SPERM IN THE SAWFLY, ATHALIA-ROSAE (HYMENOPTERA)

Sperm of the turnip sawfly Athalia rosae (Hymenoptera) were frozen in liquid nitrogen without cryoprotectant, and were stored for weeks at -80 degrees C. The sperm, upon thawing, were non-motile and had abnormal morphology. They were, nevertheless, able to fertilize micro-injected mature oocytes which developed to fertile adults. The fertilization rate was sufficiently high for the practical preservation of the mutant stocks, but was lower than obtained using fresh sperm. These results indicate that simple frozen sperm can be regarded as a fully capable genetic reserve in systems in which the micro-injection of oocytes is possible.