Spermatodesm reorganization in the spermatophore and in the spermatheca of the bushcricket Tylopsis liliifolia (Fabricius) (Orthoptera,Tettigoniidae)

Spermatozoa of Tettigoniidae are usually transferred to the female by means of a spermatophore which is also the site of feather-shaped spermatodesm formation. These spermatodesms are then transferred to a spermatheca, composed of a spermathecal duct and of a seminal receptacle, involved in storing spermatozoa. In order to extend the knowledge about sperm transfer and spermatodesms reorganization in the Tettigoniidae, a morpho-structural investigation was carried out on spermatophore and spermatheca of Tylopsis liliifolia and on the reorganization of the gametes from the spermatophore. Our results show that the spermatodesms undergo disorganization in the spermatophore; unlike other Tettigoniidae, however, feather-shaped spermatodesms are never found. The epithelium of the spermatheca consists of two cell types, the cuticle-forming and the gland cells, with secretory features. The gland cells, absent in the distal tract of the seminal receptacle, release their secretion in a “reservoir” where an efferent duct opens. In the distal tract of the spermathecal duct, adjacent epithelial cells show diversified ultrastructural characteristics whose probable role is discussed. A particular feature of T. liliifolia is the genesis of the feather-shaped spermatodesms in the seminal receptacle. This feature and the peculiar organization of the feather-shaped spermatodesm are a possible autapomorphy of T. liliifolia.     

Formation and rearrangement of spermatodesms in males of some Orthoptera Tettigoniidae

In the male genital tract of Tettigoniidae, the spermatodesms are composed of a limited number of spermatozoa whose nuclei and acrosomes are covered by a mucous cap. The formation of the cap begins in the testicular cyst during the lengthening of the apical prolongations of the spermatids and the spermatids’ simultaneous division into small bundles or spermatodesms. The cap material is formed from a loosely arranged material in the lumen of the cyst, probably produced by the secretory activity of the delimiting cells. Another characteristic aspect of the Tettigoniidae is the rearrangement of the cap inside the spermiduct that seems to start when material from the lumen of the organ enters from the basal part of the cap. Except for the fibrils of the peripheral lamina, the fibrils of the cap undergo a marked degradation process. The final organization of the spermatodesm cap is reached inside the seminal vesicles; it consists of the fibrillar peripheral lamina delimiting an interior made up of loosely arranged fibrils immersed in a finely granular matrix.     

Fine structure of male genital tracts of some Acrididae and Tettigoniidae (Insecta: Orthoptera)

A morphological, histological and ultrastructural study was carried out on the spermiducts and seminal vesicles of some species of Acrididae and Tettigoniidae. In all the species examined, the spermiducts and seminal vesicles have a monolayered secretory epithelium. Only the species of Acrididae have the sac with a flattened epithelium. Furthermore, in the most distal tubule region of the seminal vesicles of Eyprepocnemis plorans plorans, a rather characteristic secretory mechanism was found: the cytoplasm of the epithelial cells contained a large vesicle delimited by tightly packed microvilli. Numerous small vesicles open into this large vesicle which gradually dilates to merge with the apical plasma membrane releasing its contents into the lumen. Spermiophagic activity was found in all the species investigated. In the Tettigoniidae, this activity was found only in some epithelial cells of the seminal vesicle wall; in the species of the Acrididae the spermiophagic activity was carried out in the spermiduct lumen by an epithelial‐type cellular group. Spermiophagic activity is discussed as well as its role in the reproduction of these insects.     

The ultrastructure of the accessory sex organs of the male rat

Summary A systematic, comparative study of the accessory sex organs of the adult male rat was carried out after intra-aortic perfusion of the pelvic organs with glutaraldehyde. It has been revealed that although the epithelial cells of the different lobes of the prostate have many features in common, it is also apparent that the cell type of the various lobes have specific ultrastructural characteristics of its own, which morphologically distinguish it from the cell type of the other lobes. I.e.: the different lobes may be identified by their specific ultrastructural feature. It is also striking that the lobes, two-by-two, have so many morphological features in common that they may be divided in 3 subgroups. Based on the appearance of amount and localisation of the different organelles, the cells of the lateral lobe and the seminal vesicle are so alike that they morphologically may be classified as one group. Similarly, the coagulating gland and the dorsal lobe form another group, while the ventral lobe as a single form a third group. The few biochemical data from the different lobes which are accessible, seem suggestive to support this subgrouping.Since the various prostate lobes and the seminal vesicles have their homologies in man, further investigation both morphologically and biochemically should be concentrated upon the different groups instead of the single lobe.The study, which describes the different lobes and cell types in detail also show structures which have not been demonstrated within the prostatic epithelium before.     

Fine structure of the spermatozoa of Crassostrea gigas (Mollusca,Bivalvia)

We describe sperm ultrastructure and acrosome differentiation during spermiogenesis in Crassostrea gigas (Mollusca Bivalvia). The sperm cell is a uniflagellated cell of the primitive type. The head region contains a rounded or conical nucleus surmounted by small acrosome. This organelle consists of a membrane-bound acrosomal granule, the contents of which have a homogeneous density, except in the anterior region, which is positive for PTA. The acrosome also surrounds the perforatorium, which includes oriented fibrillar elements: this is the axial body. The middle piece contains four mitochondria encircling two perpendicular centrioles. The distal centriole is provided with a system of mechanical fixation to the plasma membrane, consisting of nine fibers in radial arrangement. The tail flagellum, about 50 m?m long, contains the usual microtubular axoneme. © 1993 Wiley-Liss, Inc.     

Spermiophagic activity in the female genital system of some species of terrestrial isopods (Crustacea,Halophilosciidae)

The females of some species of the family Halophilosciidae receive in the course of mating a quantity of sperm considerably redundant with respect to the number of eggs that can be fertilized; this is possible thanks to the peculiar morpho-functional organization that characterizes their genital system and that allows them to store the sperm not only in the great seminal receptacle but also within the ovary. While most of the sperm stay free in the lumen of the seminal receptacle, a part of those present in the ovary undergoes a process of capture by the follicular cells with consequent internalization within endocellular cavities. This process concerns exclusively the immotile tail, that characterizes the peculiar spermatozoon of the isopods and which is essentially of proteic nature. After their capture the sperm tails undergo a gradual process of digestion, which seems to be apparently realized without the intervention of lysosomes. The possible role of this spermiophagic activity might be to represent a significant trophic paternal investment aimed at improving the fitness of the female and of the offsprings.     

优雅蝈螽雄性附腺的超微结构及其腺管提取物对精子束的作用

为阐明优雅蝈螽Gampsocleis gratiosa Brunner von Wattenwyl雄性附腺的结构与功能的关系, 本文利用透射电镜(transmission electron microscope, TEM)技术研究了优雅蝈螽雄性附腺的超微结构, 利用微分干涉相差显微镜(differential interference contrast microscope, DIC)技术并结合雄性附腺匀浆提取物与精子束在体外的短暂培养, 研究了优雅蝈螽雄性附腺对精子束的作用。结果表明： 优雅蝈螽雄性附腺3类腺管组织结构相似, 腺管管壁为单层上皮细胞, 缺少内表皮, 说明其来源于中胚层。上皮细胞富含粗面内质网、 线粒体、 高尔基体, 具有分泌细胞的特点。腺管管腔中分泌物有4种形态, 即电子透明的物质、 电子致密的颗粒物质、 细纤维状物质以及绒球状物质。上皮细胞的分泌方式主要有2种, 即顶质分泌和局部分泌。乳白短腺管的匀浆提取物参与了帽状精子束解聚的过程, 乳白长腺管和透明腺管的匀浆提取物有维持精子束活性的作用。本研究结果为进一步阐明螽斯雄性附腺的生理功能奠定了基础。     

优雅蝈螽与暗褐蝈螽精子束的显微观察

本文应用微分干涉相衬法对优雅蝈螽Ｇampsocleis gratiosa Brunner von Wattenwyl和暗褐蝈螽G. sedakovii （Fischer von Waldheim） 雄性精巢管基部、输精管、贮精囊和精包,及雌性受精囊中精子束的形态变化进行了观察,对探讨螽斯近缘种的生殖隔离机制和生殖生物学具有重要意义.结果表明：这两种蝈螽的精子束通过精包转移到雌性受精囊后,精子束的形态发生了显著变化.精巢管基部的精子为游离的单个精子;输精管、贮精囊和精包中精子成束排列形成较分散的精子束,精子束头部包裹有粘液帽;雌性受精囊中的精子束的精子呈羽状排列,精子的头部汇集在中央轴上.两种蝈螽精子束形态差异不显著.     

Ultrastructural changes in the neurohypophysis of the aged male rat

Summary The neurohypophyses (neural lobes of the pituitary) of young adult (3–6 months) and aged (12–30 months) male rats were studied by means of electron microscopy. Stereomorphometric analyses were performed to determine the size, number and relative volume of the hormone-containing vesicles. The principal observations included: 1) the conspicuous depletion in aged rats of the granular hormone-containing vesicles from the axon terminals and the Herring bodies, with a decrease in the relative volume fraction of the vesicles from 4.8 Vv % in the control animals to 1.1 Vv % in the aged rats; 2) a change in the size-distribution of the hormone vesicles; 3) an increase in the extracellular space around the nerve terminals, axons and capillaries; and 4) lipid accumulations and signs of activation in the pituicytes. The possible physiological significance of the findings is discussed in the light of several regulatory functions known to be altered during the process of ageing.     

Chromatin condensation and acrosome development during spermiogenesis of Ensis ensis (Mollusca,Bivalvia)

We describe chromatin condensation and acrosome development during spermiogenesis of Ensis ensis. The overall shape of the mature spermatozoon corresponds to the primitive type. The nucleus is oval and on its superior pole there is an elongated acrosome; the middle piece contains four mitochondria around the centriolar complex. The condensation of the nuclei seems to occur in three steps: first the diameter of chromatin fibers increases slightly from 17 to 20 nm; second, in midspermatids fiber pairs coalesce; and third, the coalescence continues by addition of other fibers until the nuclei become highly compacted. Chromatin changes are related with nuclear protein composition. Small proacrosomal vesicles show two regions of different electron density. At a later stage they fuse to give a single, spherical vesicle in round spermatids, which migrates to the upper pole and transforms into a tapered acrosome (18 μm long) with a central channel filled with finely fibrous material. © 1994 Wiley-Liss, Inc.     

Ultrastructure of the male reproductive accessory glands in the medfly Ceratitis capitata (Diptera: Tephritidae) and preliminary characterization of their secretions

The morphology and the ultrastructure of the male accessory glands and ejaculatory duct of Ceratitis capitata were investigated. There are two types of glands in the reproductive apparatus. The first is a pair of long, mesoderm-derived tubules with binucleate, microvillate secretory cells, which contain smooth endoplasmic reticulum and, in the sexually mature males, enlarged polymorphic mitochondria. The narrow lumen of the gland is filled with dense or sometimes granulated secretion, containing lipids. The second type consists of short ectoderm-derived glands, finger-like or claviform shaped. Despite the different shape of these glands, after a cycle of maturation, their epithelial cells share a large subcuticular cavity filled with electron-transparent secretion. The ejaculatory duct, lined by cuticle, has epithelial cells with a limited involvement in secretory activity. Electrophoretic analysis of accessory gland secretion reveals different protein profiles for long tubular and short glands with bands of 16 and 10 kDa in both types of glands. We demonstrate that a large amount of accessory gland secretion is depleted from the glands after 30 min of copulation.     

On the mechanism of sperm release in three gobiid fishes (Teleostei: Gobiidae)

Synopsis In fish, gamete release is commonly assumed to be synchronous in externally inseminating fishes. By collecting and counting the number of sperm and eggs released during separate matings in three demersal spawners, the mediterranean gobies, Zosterisessor ophiocephalus, Gobius niger, and Knipowitschia panizzae, we observed that gametes are released asynchronously. Males release sperm before females start laying their eggs. Sperm is released in the form of sperm trails laid on the nest surface; subsequently active spermatozoa leave the trails and move in the water for several minutes. Sperm trails consist of bands of viscous material in which sperm is embedded. In most cases eggs are not laid directly over the sperm trail, suggesting that sperm may contact the eggs after the latter are released in the water. Male sperm duct glands, seminal vesicles, known to secrete mucosubstances, are likely involved in the production of sperm trails. The possible influence of this mode of insemination on the mating style of marine gobies is discussed.     

Morphological and ultrastructural organization of the male genital apparatus of some Aphididae (Insecta, Homoptera)

Ultrastructural investigations on the amphigonic reproductive mechanisms in Aphidoidea (Homoptera, Sternorryncha) species, of which little is known in the literature, can provide useful information on their reproductive biology. Morphological and ultrastructural investigations were carried out on the reproductive tract and on spermatozoa from sexually mature males of five species belonging to three subfamilies of Aphidoidea. The organization of the reproductive tract and of spermatozoa appears simple and similar in the examined species. Each testis consists of three follicles containing many cysts arranged in a progressive order of maturation from the distal to the proximal tract; spermiogenesis only occurs in sexually mature males, ending with the organization of sperm bundles. Gametes are neatly arranged in each bundle and kept together by a cap showing a particular organization. The distal tract of each spermiduct is enlarged and full of gametes; close to the testis the two spermiducts merge together, except in Drepanosiphum platanoidis where the spermiducts run independently. The various tracts of each examined gland showed no peculiar differences either in the same species or among the species. Some interesting hypotheses are proposed in this work about the probable roles of the investigated structures in the reproductive mechanisms of these insects.     

Sperm morphology and arrangement along the male reproductive tract of the butterfly Euptoieta hegesia (Insecta: Lepidoptera)

Summary

The present study was undertaken to describe the morphological and organizational modifications that occur in apyrene and eupyrene spermatozoa along the male adult reproductive tract of the butterfly, Euptoieta hegesia. Testis, vas deferens, vesicula seminalis and ductus ejaculatorius were studied by transmission electron microscopy. In the testis, both sperm types are organized into cysts; apyrene sperm are devoid of extracellular structures while eupyrene ones have lacinate and reticular appendages. In the testis basal region, both sperm pass through an epithelial barrier and lose their cystic envelope. The eupyrene morphological and organizational modifications are more drastic than the apyrene ones. From the vas deferens to the ductus ejaculatorius, apyrene sperm are dispersed in the lumen and acquire several concentric layers that are formed by the folding of their abundant cell membrane. The apyrene distribution observed here suggests that their functions include eupyrene transportation. Eupyrene sperm, however, remain aggregated along the tract. In the vas deferens, they are covered by a filamentous material that develops into a homogeneous matrix surrounding the spermatozoa coat in the vesicula seminalis and the ductus ejaculatorius. Eupyrene sperm undergo complex morphological changes that include the loss of lacinate appendages and the formation of a dense and heterogeneous extracellular coat. The formation of the matrix and the coat in eupyrene extratesticular sperm is related to the loss of lacinate appendages. These changes are in general extracellular and are probably important for sperm maturation.     

Acoustic satellite behaviour in the Australian bushcricket Elephantodeta nobilis (Phaneropterinae, Tettigoniidae, Orthoptera)

Male and female Elephantodeta nobilis duet with the female responding to the male's long and complex call. The duetting male's call consisted of four parts, described here as parts A, B, C and D. We found that the female replied 570 ms after the male's D pulse, which followed the extended part B and short click of part C. Noncalling males were attracted to the duet and often used satellite tactics by inserting a volley of clicks 200 ms before the alpha male's D pulse. Satellite males used part C of the alpha male song to cue their own call and this inserted call induced females to reply earlier compared with the alpha male call alone. Alpha males often extended their calls with additional D-type calls and so we examined the effectiveness of these calls as countermeasures to satellite calling. There was no influence of this alpha strategy on the satellite's propensity to call although more calls from the alpha male did cause the female to reply more frequently. We also examined the effect of relative intensity of alpha and satellite calls on the female's reply. Reduced satellite intensity increased the variance in the timing of the female response. Finally, we tested the effectiveness of the satellite's call on female phonotaxis within a two-speaker arena. Although females preferred the alpha male they were nevertheless attracted to the satellite calls regardless of the latter's relative intensity. We discuss the possible role of satellite calling as a novel conditional strategy. Copyright 2000 The Association for the Study of Animal Behaviour.     

Multiple origin of flightlessness in Phaneropterinae bushcrickets and redefinition of the tribus Odonturini (Orthoptera: Tettigonioidea: Phaneropteridae)

The possession of wings and ability to fly are a unifying character of higher insects, but secondary loss of wings is widespread. Within the bushcrickets, the subfamily Phaneropterinae (Orthoptera: Tettigonioidea) comprises more than 2000 predominantly long-winged species in the tropics. However, the roughly 300 European representatives are mainly short-winged. The systematics of these radiations have been unclear, leading to their unreliable formal treatment, which has hindered analysis of the evolutionary patterns of flight loss. A molecular phylogeny is presented for 42 short-winged species and members of all European long-winged genera based on the combined data from three nuclear gene sequences (18S, H3, ITS2). We found four phylogenetic lineages: (i) the first included the short-wing species of the genus Odontura; (ii) a further branch is represented by the South-American short-winged Cohnia andeana; (iii) an assemblage of long-wing taxa with a deep branching pattern includes the members of the tribes Acrometopini, Ducetiini, Phaneropterini, and Tylopsidini; (iv) a large group contained all short-winged taxa of the tribe Barbitistini. Phaneropterinae flightlessness originated twice in the Western Palaearctic, with a number of mainly allo- and parapatrically distributed species of the Barbistini in Southeastern Europe, and the Middle East and a limited number of Odontura species in Northern Africa and Southwestern Europe. Both short-winged lineages are well separated, which makes it necessary to restrict the tribe Odonturini to the West-Palaearctic genus Odontura. Other flightless genera previously included in the Odonturini are placed as incertae sedis until their phylogenetic position can be established.     

Autoradiographic investigation of sperm transit through the male mouse genital tract after tritiated thymidine incorporation

The transit of spermatozoa in the genital tract of the male mouse was investigated by quantitative light microscopic autoradiography after intraperitoneal injection of tritiated thymidine. Transit duration in the caput and the corpus of the epididymis was shown to be 3 days; the total duration of transit in the genital tract was 5 days. These findings indicate that the time required for the transit of spermatozoa in the epididymal caput and corpus was comparable to that calculated in other mammals studied. However, the duration of sperm storage in the epididymal cauda appeared to be shorter than that previously reported for rodents.     

Spermiogenesis and sperm ultrastructure in Cichla intermedia with some considerations about Labroidei spermatozoa (Teleostei, Perciformes, Cichlidae)

Spermiogenesis and spermatozoal structure were studied in Cichla intermedia, a primitive species of Neotropical Cichlids. The analysis shows that spermiogenesis is characterized by chromatin compaction, flagellum development, nuclear rotation, nuclear fossa formation and residual cytoplasm elimination. In the spermatozoa, the head is round, the nucleus contains highly condensed filamentous clusters of chromatin and an acrosome is absent. The nuclear fossa is slightly eccentric and shows a projection that penetrates into the nuclear outline. The proximal centriole is located in the initial segment of the nuclear fossa. The midpiece and the cytoplasmic channel are long. The mitochondria, about 10 in number, are round or slightly elongated, disposed in two layers around the initial segment of the flagellum. The flagellum has a classical 9+2 axoneme and two lateral fins. The data available show that no characteristics of spermiogenesis or spermatozoa are exclusively found in members of the suborder Labroidei. However, three characteristics seem to be exclusively observed in Cichlidae: (1) compact filamentous clusters of chromatin; (2) slightly eccentric nuclear fossa; and, (3) number of mitochondria.     

Cytogenetics studies in thirteen brazilian species of Phaneropterinae (Orthoptera: Tettigonioidea: Tettigoniidae): main evolutive trends based on their karyological traits

The thirteen species of Phaneropterinae here studied can be arranged in four different groups according to their basic karyological traits. All of them share the same kind of chromosomal sex determining mechanism with X0 (male sign) and XX(female sign). The X chromosome differs among species and always appears heteropycnotic during prophase I, it is the largest in the set and segregates precociously during anaphase I. Among the species, the karyotypes varies in fundamental number between 31 to 21. The meaning of these significant changes in the karyotypes in relation to the phylogeny within some large taxonomic group of species is discussed.     

扩张莫尼茨绦虫(圆叶目:裸头科)精细胞分化、精子形成及精子形态

本项研究应用光学显微镜、扫描和透射电子显微镜,观察了扩张莫尼茨绦虫的精细胞分化、精子形成全过程及精子的精细结构。扩张莫尼茨绦虫的精细胞分化过程为：1)初级精原细胞主要发生于幼节的睾丸滤泡中;2)次级精原细胞发生不完全分裂形成16个细胞一簇的初级精母细胞群,以共同的中央细胞质相连;3)初级精母细胞的特征为细胞核中出现联会复合体结构;4)紧接着的第二次成熟分裂,产生64个由中央细胞质相连的细胞核较小的精细胞。精子形成始于精细胞中分化区的形成,成熟精子缺乏线粒体,具有质膜和冠状体、1—4个领域排布的质膜下皮层微管,细胞质中存在电子致密的颗粒状物质,具一个不规则形态的细胞核,具有“9 1”类型的轴丝构造,缺乏轴丝周围鞘。从精子的纵切面上可将精子区分为5个区段(Ⅰ一Ⅴ区)。在精子形成过程中,中心粒基部出现螺旋形小根结构在寄生虫中为首次报导;成熟精子具有游离鞭毛,在绦虫中为首次发现[动物学报49(3)：370—379,2003]。