Ultrastructure Of Male Reproductive System And Spermatozoa In Five Planthopper Species

The superfamily Fulgoroidea is an important group in Auchenorrhyncha of the Order Hemiptera,some species in this group are economically significant pests of major agricultural crops by pierce-sucking of juice and transmitting plant pathogens.However,the phylogeny of this superfamily remains controversial so far,relationships between some groups unclear for a long time.More evidence is needed to slove the problems.Comparative study on ultrastructure of male reproductive system and spermatozoa of planthoppers,can help to better understand the reproduction and behavior,and also can provide more data to species recognization and phylogenetic relationship exploration.In this study,the ultrastructure of mature male reproductive system and spermatozoa of five species of planthoppers,i.e.Pochazia shantungensis(Chou & Lu,1981),Ricania speculum(Walker,1851)and Euricania clara Kato,1932 from Ricaniidae,Lycorma delicatula(White,1851)from Fulgoridae,Dictyophara sinica Walker,1851 from Dictyopharidae,were studied through morphological,histlogical and ultrastructure observation by means of permanent paraffin sections,optical microscope and transmission electron microscope.The main results are as follows:1.There is no significant difference in the ultrastructural composition of the internal genitalia in male reproductive system of the five planthoppers.Spermatophore or spermatozoa in each cysts of testis tubular were observed and the results show that the ultrastructure of each of testis tubular mainly contain muscle sheath,basal membrane,epithelial cell layer and the lumen with the germ cell.A lot of multilamellar bodies,rough endoplasmic reticulum,golgi complex,mitochondria,vesicles and secretions are visible in the epithelium layer.A series of microvilli in the anterior part of epithelial layer near the lumen and a large number of sperm cells or spermatozoa in lumen were found.The nucleus of chromatin condensed,the acrosome formed by the proacrosomal granules and the golgi complex made up the head of sperm,while biggish nebenkern formed by the fusion of mitochondria in sperm cell finally transformed into a pair of mitochondrial derivatives on both sides of axoneme,becoming a part of the sperm flagellum.2.The seminal vesicle of five planthoppers consist of tunica externa,muscle sheath,basal membrane,epithelium and lumen,the nucleus of epithelium irregular,with a lot of dense secretions and a series of microvilli in epithelial layer;in addition,the microvilli have some secretory granules into the lumen which brimmed with different forms of mature sperm.3.The ejaculatory duct of five planthoppers mainly consist of annular thicker muscle sheath,epithelium layer and lumen.The muscle sheath much developed,the microvilli are visible in the lumen,and the double-tube cavity near the seminal vesicle become single-tube cavity.The mature sperm in the seminal vesicle finally passed into female through ejaculatory duct.4.The accessory gland of planthoppers fairly developed,its ultrastructure differs from testicular follicle,seminal vesicle and ejaculatory duct.The epithelium cells relatively dense,with abundant types of secretions in accessory glands.5.The mature spermatozoa of five planthopper species held together in the form of coiled sperm bundles.Single sperm without polymorphism,formed by linear head,neck region and distinct long flagellum.The head include bilayered acrosome and elongated nucleus;the neck region has centriole and centriolar adjunct;the long flagellum mainly composed of a pair of mitochondrial derivatives,a pair of developed accessory bodies and axoneme with the typical 9+9+2 microtubule pattern;they are parallel to each other throughout most of the length of the flagellum.The mitochondrial derivatives are symmetrical in size and diameter.Each mitochondrial derivative has evident parallel cristae arranged in the periphery,and cristae perpendicular to the axis of the mitochondrial derivative.Two accessory bodies are dense dark in color,symmetricaly arranged on both sides between the axoneme and mitochondrial derivatives.Mitochondrial derivatives and accessory bodies gradually smaller and finally disappeared before the axoneme in the process of spermatid elongation.6.The sperm morphology and ultrastructure of the three ricaniid species are similar,without big difference in length of sperm.The ultrastructure of well-developed fishhook-shaped accessory bodies and D-shaped mitochondrial derivatives in flagellum appear consistent,it is speculated that this may be common feature of the family Ricaniidae.Furthermore,the sperm morphology and ultrastructure of Lycorma delicatula of Fulgoridae and Dictyophara sinica of Dictyopharidae are similar as well.Compared with Ricaniidae,the sperm morphology and ultrastructure of these two species are longer,both have quite well-developed spiral accessory bodies and club-shaped mitochondrial derivatives in flagellum.It is speculated that the Fulgoridae is closer to the Dictyopharidae and these two families may be constituted a sister group.This study may provide scientific data for phylogenetic analysis of the the superfamily Fulgoroidea.