Ultrastructure of Single and Multiple Diploid Honeybee Spermatozoa

SummaryDiploid drone honeybees were reared by Woyke's method and the ultrastructure of diploid and haploid spermatozoa was investigated. The ultrastructure of diploid spermatozoa is very similar to that of the haploid ones, but the diploids are larger. The length of the aero some and the nucleus of a diploid spermatozoon are 151% and 139% respectively of those for a haploid one. The diameter of the tail of a diploid spermatozoon is 115% of that of a haploid one, A single axon e me with an arrangement of 9 + 9 + 2 fibrils is present in a diploid spermatozoon. The direction of helical grooves is the same on both mitochondrial derivatives in diploid spermatozoa, whereas it is opposite on the two derivatives in haploid spermatozoa. The volume of a diploid spermatozoon is about twice that of a haploid one.Among ordinary diploid spermatozoa were also found double ones, containing two axonemes and four mitochondrial derivatives in their tails, and triple ones, containing three axonemes and six mitochondrial derivatives. The diameters of the tails of double and triple spermatozoa are 165% and 195% respectively of the diameter of the tail of a single diploid spermatozoon, but the diameter of each axoneme is the same whether the spermatozoon is single or multiple. In multiple spermatozoa the normal association of a pair of mitochondrial derivatives with each axoneme is not seen. It is concluded that multiple spermatozoa are not formed by fusion of mature spermatozoa, but probably arise by premature spermiogenesis in spermatoids that have not yet separated.