Study On Spermatozoa Ultrastructure In Tettigonioidea

The thesis represents the study on the spermatozoa ultrastructure of 20 species in Tettigonioidea, Orthoptera. Out of them, 10 species belong to Conocephalidae, 5 to Phaneropteridae, 2 to Tettigoniidae, 1 to Mecopodidae, 1 to Pseudophyllidae and 1 to Meconematidae. The study aims to figure out interfamilial, intergeneric and interspecific differences of spermatozoa ultrastructure for potential use in taxonomy and phylogeneticinference of the superfamily.The spermatozoa uttrastructure of these species was observed using JEM-2000EX and TECNAI-10 transmission electron microscope, after double fixation of live material in glutraric-aldehyde and osmic acid. Mdst of the materials investigated were collected from Beibei, Chongqing.The main results and conclusions of the study are as follow:1. The spermatozoa ultrastructure in ConocephalidaeThere is not distinct difference in spermatozoa ultrastructure between species in the genus Conocephalus of this family. The ultrastructure of the genus can be summarized as: 1) acrosomal complexes of spermatozoa are similar in cross-section; 2) crystallization and shape of mitochondrial derivatives are nearly same in cross-section, and two lateral additional fibrous structures flanking the axoneme are smaller accessory bodies; 3) centriolar adjunct has falciform centriolar adjunct process; 4) the nuclei of spermatozoa appears falciform in cross-section. Its anterior part, which inserts laterally in the acrosomal complex, appears mostly crescent-shaped and similunar in cross-section.Hexacentrus is suggested to be a specific group. Its spermatozoa has a quite produced extra-acrosomal layer and "Y"-shaped membranous cisterns in cross-section.The pentalaminar oganelle in the centriolar adjunct was observed in Conocephalusmelas(De Haan, 1842), Pseudorhynchuspyrgocoryphus(Kamly, 1920)and Hexacentrus unicolor Audin&Serville, 1831. This character is commonly present in these three species but not observed in others investigated in this family.The crystallization and shape of mitochondrial derivatives, and the shape of nueclei in cross-section are consipicuously different among genera of this family. They can be used as intergeneric diagnostic characteristics after further work.2. The spermatozoa ultrastructure in PhaneropteridaeThe spermatozoa ultrastructure in Phaneropteridae is characterized by lanceolate acrosomal complex, quite produced extra-acrosomal layer and an additional accessory extra-axonemal tubule (except for Mecopoda nipponensis) between axoneme and mitochondrial derivatives besides two accessory bodies.The nuclei, crystallization and the shape of mitochondrial derivatives are conspicuously different in cross-section among genera and may be used as general identification of this family. Interspecific difference in Elimaea was even observed for thelater.3. The significance of spermatozoa ultrastructure in systematicsSpermatozoa among families of Tettigonioidea are conspicuously different in acrosomal complex and crystallization of mitochondrial derivatives in cross-section.The nuclei of spermatozoa in cross-section in this superfamily are conspicuously different among genera of each a family. It can be regarded as a good intergeneric diagnostic characteristic.Centriolar adjuncts of spermatozoa in cross-section in this superfamily are not suitable for a general identification, for its anterior and posterior parts are not same in cross-section.Crystallization and the shape of mitochondrial derivatives in cross-section can be regarded as intergeneric diagnostic characteristic in many families. It can even be an interspecific diagnostic characteristic in Ruspolia of Conocephalidae and Elimaea of Phaneropteridae.