Ultrastructural features of spermatozoa and their phylogenetic application in Zaprionus (Diptera, Drosophilidae)

The genus <i>Zaprionus</i> consists of approximately 60 species of drosophilids that are native to the Afrotropical region. The phylogenetic position of <i>Zaprionus</i> within the Drosophilidae family is still unresolved. In the present study, ultrastructural features of spermatozoa of 6 species of <i>Zaprionus</i> as well as the species <i>Drosophila willistoni</i> and <i>Scaptodrosophila latifasciaeformis</i> were analyzed. The ultrastructure revealed that the species have the same flagellar ultrastructure. Two mitochondrial derivatives, one larger than the other, close to the axoneme were present, primarily in <i>D. willistoni</i> (subgenus Sophophora). Except for <i>Z. davidi</i> and <i>Z. tuberculatus</i>, the analyzed species had paracrystalline material in both mitochondrial derivatives. Moreover, the testes showed 64 spermatozoa per bundle in all of the species. In the cluster analysis, 6 <i>Zaprionus</i> species were grouped closely, but there were some incongruent positions in the cladogram. The results indicated that sperm ultrastructure is an important tool for elucidating the phylogeny and taxonomy of insects.