| Abstract: | In cross sections of developing spermatid tails of D. melanogaster, the angular positions of the mitochondrial derivatives relative to the axoneme are precisely defined at each stage of development. Nearly mature sperm in the coiling stage, however, exhibit a variable angular relation between the axonome and the rest of the tail. A similar variation is also found among cross sections of mature sperm tails. These observations, together with other morphological evidence, are interpreted as indicating limited rotational freedom between the axoneme and the rest of the tail in mature sperm. Such a freedom seems to be related to the swimming pattern of sperm and the fertilization process. It is suspected that specific shapes and natures of mitochondrial derivatives in sperm tails of insects are related to a particular swimming pattern of sperm, which must be highly precise in order to meet the requirements of species-specific modes of fertilization. |
