Morphology And Ultrastructure Of The Reproductive System In Deltocephalinae

Insects are extremely successful animals and their success is at least in part attributable to efficientreproductive capacities. The reproductive system of insects, a collection of organs that work together toperform several functions for the purpose of producing new life, has undergone extensive diversificationand exhibits a remarkable variety of forms. Comparative morphological and ultrastructural investigations ofinsect reproductive systems, can contribute not only to better understanding of the reproductive process andbehavior, but also may help elucidate the evolutionary history of the group. Deltocephalinae is the largestsubfamily of leafhoppers in Cicadellidae and cause some seriously damage by their feeding andtransmitting plant pathogens. Studies on the morphology and fine structure of reproductive system inDeltocephalinae are relatively few. Here, the fine morphology and ultrastructure of the reproductive systemand mature spermatozoa of three leafhoppers Psammotettix striatus (Linnaeus), Japananus hyalinus(Osborn) and Exitianus nanus (Distant), representing three different tribes of the largest leafhoppersubfamily, Deltocephalinae, were examined by light and transmission electron microscopy, aiming tocontribute to the knowledge of reproductive biology, as well as to provide information on the systematicstudy of this groupThe gross morphology and ultrastructure of the reproductive system of these three species ofDeltocephalinae is similar to that of other Cicadellidae and related Auchenorrhyncha. The malereproductive system consists of two testes, two vasa deferentia, a pair of seminal vesicles, two accessoryglands, two lateral ejaculatory ducts and a single common ejaculatory duct. The pair of testis are symmetricand contain testicular follicles, which gather together and link with a vas deferens to the seminal vesicles.The seminal vesicles are without an outer membrane package, in which lateral ejaculatory ducts join withthe posterior of seminal vesicles. A couple of accessory glands connect to the posterior seminal vesicles andthe anterior of the lateral ejaculatory ducts. Then the pair of accessory glands merge to form commonejaculatory duct. The testicular follicles, outside-in, consist of: testicular follicle membrane, muscularsheath, epithelium, lumen and spermatids. Spermiogenesis occurs in the testicular follicles. Then thespermatids show various stage of development: nebenker, proacrosomal granules, acrosome, centriole,axoneme, extension of nucleus, chromatin condensation, and so on. The paired seminal vesicles are hollowcapsula stractula and contain a muscular sheath, epithelium and lumen. The lumen is full of sperms with thehead embedded in a homogenous matrix to form spermatodesms. The male accessory glands containmainly muscular sheaths and epithelia. The epithelium has numerous lamellar endoplasmic reticula and vesicular endoplasmic reticula, and the irregular secretory granules are gathered together.The female reproductive system is composed of a ligament, a couple of ovaies, two lateral oviducts, acommon oviduct, accessory glands, a spermatheca and a bursa copulatrix. Equal number of ovarioles formsa pair of ovaies, which link with a lateral oviduct and the lateral oviduct converges to form a commonoviduct. Accessory glands connect with the base of the common oviduct and bursa copulatrix. Thespermatheca lie near the posterior of common oviduct and its appearance is spherical. The germarium ofovarioles consist of a basal lamina, somatic stem cells and trophocytes and in the vitellaria an oocyte issurrounded by round follicular cells. The common oviduct consists of a muscular sheath, epithelium andlumen, and a few spermatozoa spread in an arborization-shaped lumen. A muscular sheath, epithelium,lumen and some special structures in lumen constitute the spermatheca with vast spermatozoa interspersedamong the lumen. The bursa copulatrix contains a muscular sheath, epithelium and lumen, and the lumenhas arborization and on the edge of the lumen is cuticle. The inflated parts consist of a spherical lumenfilled with microvilli on internal wall. The female accessory glands contain a muscular sheath, epitheliumcells and lumen. Epithelium cells consist of many secretory vesicles, lamellar endoplasmic reticulum andvesicular endoplasmic reticulum and two kinds of secretory granules.There are some differences among the reproductive systems of Exitianus indicus (Distant),Psammotettix striatus (Linnaeus) and Japananus hyalinus (Osborn). In the male reproductive system, thethree species differ in the number and shape of testicular follicles, the shape of the seminal vesicle, and thesize and color of the accessory gland. There are6testicular follicles in Exitianus indicus (Distant) andPsammotettix striatus (Linnaeus). They are pyriform and plae yellow. Japananus hyalinus (Osborn) hasseven oval and white testicular follicles. The seminal vesicles in Exitianus indicus (Distant) andPsammotettix striatus (Linnaeus) appear oval and yellow. In Japananus hyalinus (Osborn) they are in closecontact, spherical and milky white. In the female reproductive system, Exitianus indicus (Distant) possessestwelve ovarioles and Psammotettix striatus (Linnaeus) has six ovarioles. Japananus hyalinus (Osborn)contains eight ovarioles.The shape and ultrastructure of spermatozoa are very similar to those of other Cicadellidae as well asother Auchenorrhyncha, comprising a conical acrosome invaginated to form a subacrosomal space, afiliform homogeneously condensed nucleus, a lamellate centriolar adjunct connecting the nucleus with themid-piece/flagellum, a long flagellum with a9+9+2axoneme pattern and two symmetrical mitochondrialderivatives with an orderly array of peripheral cristae, and two drop-shaped accessory bodies. They may bedistinguished by the size of the sperm, and the shape of the nucleus, accessory bodies, and paracrystallineregion of mitochondrial derivatives. The fine morphology and ultrastructure of spermatozoa are illustrated,along with a brief discussion on the implications there strucuture on the classification and phylogeneticanalyses of the subfamily.