Sexual selection affects the sizes of the mammalian prostate gland and seminal vesicles

The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity,and the chemical complexity of their products,little is known about the possible effects of sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of 89 species and 60 genera representing 8 Orders of mammals. The sizes of the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size (corrected for body weight) correlate positively with relative testes size in this sample; this finding remains highly significant after application of procedures to correct for possible phylogenetic biases in the data set. The accessory reproductive glands are also significantly larger in those mammals which have large relative testes sizes,and in which the likelihood of sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of the mammalian prostate gland and seminal vesicles.     

Morphological changes in the male accessory glands and testes in Vespula vulgaris (Hymenoptera,Vespidae) during sexual maturation

Abstract. The present study documents the pace of accessory gland and testes degeneration in the wasp Vespula vulgaris by means of a histological and metric approach, that has not been carried out for social wasps so far. To a certain extent, comparison is made with the degenerative processes of the mucus glands of the honeybee drone. In V. vulgaris, no generative tissue is left by the end of 9 d of age, and so degeneration is a fast process. The three different parts of the accessory glands (muscle layer, gland epithelium, and lumen) change with respect to age. The secretory cells of the epithelium reach their maximum activity during the first days of adult life, which results in a maximally filled gland lumen by 9 d. We also provide, for the first time, a histological study of testes degeneration for this species. At eclosion, well‐defined cystic structures are still visible, whereas at 9 d, it is no longer possible to distinguish different cystic structures. The diameter of the testes decreases with respect to age.     

Eversible abdominal vesicles and some observations of the male reproductive system of the spoon wing lacewing Palmipenna (Neuroptera: Nemopteridae)

The anatomy and histology of the abdominal eversible vesicles and the male reproductive tract of the spoonwing lacewing Palmipenna (Neuroptera: Nemopteridae) have been examined. The eversible vesicles open as a pair of large bulbous sacs between tergites five and six, each folding into halves during retraction. They consist of highly pleated cuticle, beneath which are typical gland cells, each having a circular or oval end apparatus surrounded by closely packed microvilli. These communicate to the surface via cuticularized channels. In spite of considerable behavioral observations, male Palmipenna were never noted with everted vesicles. Even during mating trials, where females were presented to males in the field, the vesicles were never everted during the attempted copulation that ensued. Our observations indicate that mate attraction is mediated by the release of a female pheromone. The function of the eversible vesicles and their associated gland cells remains unknown, and their structure appears to be unique to the Nemopteridae. The reproductive tract is similar to that of other Neuroptera, consisting of a pair of five-lobed testes, a medium-to-large pair of seminal vesicles, and three pairs of accessory glands. The major accessory glands are surrounded by circular and longitudinal muscle, and are lined by an epithelium, the cells of which presumably secrete the amorphous rods of material always present in this pair of glands. The sperm in the seminal vesicles are elongate, with a pointed head and a 9 + 9 + 2 configuration in the flagellum. A single spermatophore, similar in shape to that described for other Neuroptera, was found occluding the bursa copulatrix of a teneral female. © 1994 Wiley-Liss, Inc.     

Antigenic homogeneity of male Müllerian gland (MG) secretory proteins of a caecilian amphibian with secretory proteins of the mammalian prostate gland and seminal vesicles: evidence for role of the caecilian MG as a male accessory reproductive gland

Whereas in all other vertebrates the Müllerian ducts of genetic males are aborted during development, under the influence of Müllerian-inhibiting substance, in the caecilian amphibians they are retained as a pair of functional glands. It has long been speculated that the Müllerian gland might be the male accessory reproductive gland but there has been no direct evidence to this effect. The present study was undertaken to determine whether the caecilian Müllerian gland secretory proteins would bear antigenic similarity to secretory proteins of the prostate gland and/or the seminal vesicles of a mammal. The secretory proteins of the Müllerian gland of Ichthyophis tricolor were evaluated for cross-reactivity with antisera raised against rat ventral prostate and seminal vesicle secretory proteins, adopting SDS-PAGE, two-dimensional electrophoresis and immunoblot techniques. Indeed there was a cross-reaction of five Müllerian gland secretory protein fractions with prostatic protein antiserum and of three with seminal vesicle protein antiserum. A potential homology exists because in mammals the middle group of the prostate primordia is derived from a diverticulum of the Müllerian duct. Thus this study, by providing evidence for expression of prostatic and seminal vesicle proteins in the Müllerian gland, substantiates the point that in caecilians the Müllerian glands are the male accessory reproductive glands.     

日本弓背蚁雄蚁生殖系统结构及其化学组成研究

【目的】雄蚁是蚂蚁巢群的重要成员,主要参与种群的繁殖。本文对日本弓背蚁Camponotus japonicus雄蚁的生殖系统结构及其化学组成进行了研究,拟为进一步开展雄蚁的生殖行为研究提供基础信息。【方法】利用光学和扫描电镜观察了雄蚁的生殖系统结构,并利用GC-MS方法分析了其化学组成。【结果】(1)雄蚁生殖系统包括1对附腺、1对输精管和射精管3部分,睾丸退化消失;附腺最为发达,肾形,乳白色;输精管简单细长,与附腺基部1/3处相连。扫描电镜下发现附腺表面平坦,包裹有发达的网状肌肉组织。(2)利用GC-MS方法检测到13种化学物质,主要以醛类、烃类和酸类为主,分别占29.31%、21.87%和20.56%,还有一些醇类(12.71%)和酯类(15.05%);含量最高的3种成分分别为十八烯醛(15.86%)、11-十六烯醛(13.45%)和9,12,15-十八碳三烯酸-2,3-二羟基丙酯(11.78%)。【结论】雄蚁生殖系统主要由附腺、输精管和射精管三部分组成,其中附腺最为发达,输精管细长,睾丸退化消失;生殖系统中含有多种化学成分,但其功能还有待于进一步的研究。     

Histology and histochemistry of the reproductive tract of the pulmonate snail,Bulinus truncatus,with observations on the effects of castration on its growth and histology

The reproductive tract of B. truncatus was investigated histologically in order to study possible effects of castration upon the accessory sex glands. In the female part of the reproductive tract—subdivided into albumen gland, oviduct, muciparous gland, oothecal gland, uterus, vagina and bursa copulatrix—13 histochemically different secretory cell types were distinguished. The majority produce different types of (acid) mucopolysaccharides. The roles of the various parts of the female tract in the production of an egg mass were elucidated by comparing the histochemistry of the egg mass to that of the female tract; the abundance and location of the cell types were also taken into account for this purpose.

The male part appeared to contain 12 histochemically different secretory cell types. These produce mainly (phospho lipoproteins together with some polysaccharides and neutral lipids.

Castration causes an acceleration of the growth of the snails. The volumes of female (albumen gland) and male (prostate gland) accessory sex glands were measured on histological sections. It appeared that growth of the albumen gland is not arrested by castration. This was not established beyond doubt for the prostate gland. The results suggest that the stimulating effects of the dorsal body hormone on the growth and synthetic capacity of the female accessory sex glands—such effects have been established for Lymnaea stagnalis—are not exerted via the ovotestis in B. truncatus.     

Anatomy and histology of the prostate and glands of Cowper in three species of neotropical bats

The reproductive accessory glands (RAG) are essential components in reproduction because their secretion products ensure survival, viability, and sperm motility. The objective of this study was to characterize and compare the morphological and histological structure of the RAG in three species of bats of the genus Sturnira (S. erythromos, S. lilium, and S. oporaphilum). The RAG complex comprise a compact gland (prostate), which surrounds the urethra, and a pair of Glands of Cowper at the base of penis. Anatomical and histologically, the prostate are differentiated in two regions, ventral and dorsal. The dorsal region has tubuloalveolar glands with secretions fine granular or accumulations of a gel‐like substance with bubbles and the ventral region, has alveolar glands with secretory cells form a single‐layer of small cells. The seminal vesicles are absent. The prostatic morphology of the three species is similar to that of other studied Stenodermatinae and Desmodontinae, but differs from other subfamilies of Phyllostomidae (Carollinae, Glossophaginae, and Phyllostominae) as that of Molossidae and Vespertilionidae. The RAG complex has no annual variation in relation to functionality or size, but it is variable depending on age (subadults and adults). This agrees with the annual reproductive pattern described for these species in these latitudes, where adult males are reproductively active throughout the year.     

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.     

Histology and histochemistry of the accessory reproductive glands in the male hairy-nosed wombat (Lasiorhinus latifrons)

Summary The accessory male reproductive glands of the hairy-nosed wombat, Lasiorhinus latifrons, are a prostate and three pairs of Cowper's glands. Component units of all are branched tubular structures of varying epithelial makeup and secretory content. The prostate has the carrotlike shape and three consecutive regions commonly found in marsupials. The regions differ in their tubular histology and histochemistry: all contain secretory globules in glandular lumina. Cowper's glands A and B are histologically identical except for the absence of interstitial mast cells from gland B: gland C is characterized by narrower tubules and larger epithelial cells. Histochemical tests for protein, carbohydrate and iron indicate that glycogen is a major secretory product of the prostate (largely posterior region), iron is also secreted (mainly posterior region) and a small quantity of acid mucin is produced (mainly central region). Glycogen is a feature also of anterior prostatic glandular epithelium and of the capping cells of the urethral transitional epithelium. Cowper's gland A has considerable protein in its secretion, gland B a neutral glycoprotein and gland C a sialomucin: the latter two also exhibit cytoplasmic glycogen in their secretory cells.     

Little-known accessory glands in female Zygaena moths (Lepidoptera, Zygaenidae)

In the female genital system of Zygaena moths, an additional pair of accessory glands is present besides the Y-shaped sebaceous gland. The term 'Petersen's glands' is proposed for these organs. Anatomy, histology, histochemistry and cytology of Petersen's glands of Zygaena trifolii are described. The sac-like glands, situated in the extreme dorsocaudal part of the abdomen, can be divided into a purely secretory part consisting of acini with large pear-shaped gland cells and a reservoir part with combined secretory and storage function. The secretory cells of the acini are penetrated by long curved ductules or secretory end apparatuses having feltwork consisting of very fine filaments. The cytoplasm is characterized by abundance of smooth tubular endoplasmic reticulum (ATER) and the presence of peroxisomes. This cytoplasmic organization is in accordance with the chemical composition of the sticky secretion, which evidently consists completely of lipids. The ultrastructure of the epithelium lining the reservoir of the glands has both traits of secretory and of transporting epithelia. Besides contributing to the secretion, it may be involved in absorption of residual aqueous phase from the contents of the reservoir.     

Ultrastructure of the Male Accessory Glands and Sperm Ducts of Cylindrotaenia hickmani(Cestoda,Cyclophyllidea)

Abstract The ultrastructure of unicellular accessory glands (= prostate glands) and external male ducts of the cestode Cylindrotaenia hickmaniare described. Accessory glands open into the lumen of the external common sperm duct (= external vas deferens). The gland cells contain abundant endoplasmic reticulum, Golgi bodies and secretory bodies, and have elongate necks that pierce the apical cytoplasm of the duct. Cell contact with the apical cytoplasm of the sperm duct is mediated by septate desmosomes. Accessory glands secrete spherical particles, with a diameter of approximately 70 nm, that adhere to spermatozoa. The roles of these accessory glands may relate to activity of the sperm or development of the female system after insemination. Paired sperm ducts arise from testes, and unite to form a common sperm duct. Each duct consists of a tubular anucleate cytoplasmic region which is supported by nucleated cytons that lie sunken in the parenchyma. The apical cytoplasm of the paired sperm ducts (= vasa efferentia) possesses apical microvilli and abundant mitochondria, but few other cytoplasmic features. The apical cytoplasm of the common sperm duct possesses sparse apical microvilli and numerous electronlucent vesicles. The male gonoducts form an elongate syncytium which is markedly polarized along the length of the ducts. The ducts also display apical–basal polarity in that sunken nucleated cytons support the apical cytoplasm which in turn has distinct basal and apical domains.     

The anatomy of the adult uropodid Fuscouropoda agitans (Arachnida; Acari), with comparative observations on other Acari

A thin, compressible, lateral suture and ventral plate overlap permit limited movement of the thick and rigid dorsal and ventral plates of Fuscouropoda agitans. Seven pairs of large dermal glands debouch onto the surface. Trochanteral rotation permits defensive leg adpresion and an insectan type of ambulation. The complex hypopharynx-pedipalpal-coxae has a buccal and cheliceral cavity separated by an atriculated epipharynx. The pharynx is Y-shaped in cross section. Extensive paired salivary glands lie above the very long and dexterous 3-segmented chelicerae, and a large pair of coxal glands debouch on coxae 1. From four blunt-ended tracheae, bundles of unbranching tracheoles extend in specific tracts to all organs. The ventriculus is small with three pairs of large caeca; a tightly packed single layer of digestive cells individually enlarged to absorb-phagocytize and digest the food. A typical mesostigmatid excretory tube is present. A typical acarine synganglion is present; mixed nerves have a basal swelling. A postulated neurosecretory organ arises from the pedipalpal nerve. The oocytes enlarge within funicular stalks from the walls of the small median ovary. A large spermatophore is stored in the seminal vesicle; fertilization occurs during oviposition. A tension hinge partially opens both male and female genital plates; closure effected by muscles acting on very long genital plate apodemes. Within sequentially produced spermatogonial cysts of the testes, meiosis is completely synchronous. A large, multilobed male accessory gland produces a large volume of seminal fluid; a mixture of at least four secretions. The origins and msertions of the body wall, genital organ, digestive tract, mouthpart and leg muscles are listed and illustrated. A comparison of anactinotrichid and actinotrichid mites indicates fundamental and consistent morphological differences in aspects of the cuticle, leg articulations, digestive system, excretory system, reproductive system and coxal glands.     

Histology,histochemistry, and emptying mechanism of the venom glands of some elapid snakes

The venom glands of several species of elapid snakes are described. The main venom gland consists of many tubules which usually contain large amounts of secretion product. The accessory gland surrounds the entire venom duct and is usually composed of uniform mucous epithelium. The epithelium lining the tubules of the accessory gland of Naja naja is composed of two distinct types of cells. Histochemical tests indicate that the main venom gland reacts with mercury bromphenol blue and PAS but not with alcian blue. The accessory gland reacts with PAS and alcian blue, and not with mercury bromphenol blue. Treatment of sections with sialidase demonstrates the presence of a sialomucin in the accessory gland. Stimulation of the muscles associated with the venom gland offers an indication of the venom expulsion mechanism of Bungarus caeruleus. A comparison of the venom apparatus of elapid and viperid snakes emphasizes marked differences in the internal anatomy of the venom glands, muscles associated with the gland, and arrangement of glandular components. The morphological differences and dissimilar venom expulsion mechanisms support the recent view of the polyphyletic origin of venomous snakes.     

Reference values for the genitalia of male dromedary before and after puberty using caliper and ultrasonography in subtropics

The aim of the present study was to characterize the dynamic changes of the testes and the pelvic genitalia in vivo in male dromedary. Eighty-one clinically healthy male dromedaries aged 1.5 to 12 years were assigned for the present study. Testicular length, breadth, and depth as well as epididymal head and tail were measured using caliper and ultrasonography. The pelvic genitalia, including bulbourethral gland, prostate, and pelvic urethra were examined using ultrasonography. The results revealed that the three dimensions of the testes and epididymal tail and head showed significant increase with age (P < 0.01). Concerning the epididymal measurements, differences between the pre- and peri-pubertal groups were not significant. Left testes tended to be larger than the right (not statistically significant) although only the breadth of the left testes in the prepubertal group was significantly larger (P < 0.05). The volume of both testes correlated positively with the age (r² = 0.91 for left and 1.00 for the right, P < 0.01). There were no significant correlations between the values measured using caliper and those by ultrasonography between groups, but the correlation was highly significant (P < 0.01) for the total number of the examined animals. There were significant and steady increases of the size of bulbourethral gland in all examined groups (P < 0.01). Pars disseminata of the prostate gland and pelvic urethra were significantly higher in sexually mature compared with prepubertal groups (P < 0.01). It was concluded that ultrasonography is a useful tool in studying the developmental changes of the testes and accessory glands of the male dromedary. The obtained data could provide a reference values for predicting camel puberty and future fertility.     

Trehalase from the bean-shaped accessory glands and the spermatophore of the male mealworm beetle,Tenebrio molitor

Summary InTenebrio molitor, male adults transfer sperm to the female via a spermatophore or sperm sac. The spermatophore is formed from secretions of the bean-shaped accessory glands (BAGs) and the tubular accessory glands (TAGs) of the male beetle. Trehalase is found in the adult BAGs. During the pupal stage, the activity in the BAGs was very low. After adult ecdysis, the total activity increased 100-fold from 0 days to 6 days and reached maximum levels at 9 days. The specific activity increased 20-fold from the time of ecdysis to 6 days thereafter. In the 10 day adult, trehalase levels in testes, seminal vesicles, vas deferens, TAGs, or ejaculatory ducts, were lower by two orders of magnitude than in the BAGs. However, the specific activity in the spermatophore was similar to that in the BAGs. Trehalases in the BAGs and the spermatophores showed very similar properties (soluble, optimum pH of 5.75 andK _m value of 5.4 mM for trehalose). Thus trehalase appears to be secreted from the BAGs and becomes incorporated into the spermatophores.Abbreviations BAG bean-shaped accessory gland - TAG tubular accessory gland     

Morphology of the male reproductive system,sperm ultrastructure and γ-irradiation of the red palm weevil Rhynchophorus ferrugineus Oliv. (Coleoptera: Dryophthoridae)

In the present study we describe the morphology of the male reproductive apparatus and sperm ultrastructure of the red palm weevil – an invasive pest of several palm tree species – as well as the most important steps of spermatogenesis. The reproductive apparatus consists of a pair of testes (each formed by two lobes) a long tube-like accessory gland, a prostate gland and a small accessory gland. Characteristic features of the sperm are 90–100 μm total length, 10 μm nucleus, two mitochondrial derivatives, two accessory bodies, one well-developed puff-like structure and a typical insect 9+9+2 flagellar axoneme. One of the methods used for the biological control of pests is the Sterile Insect Technique (SIT), for the evaluation of which we make a preliminary comparison of the sperm ultrastructure of non-irradiated and irradiated weevils (at a dose of 80 Gray).     

B-mode ultrasonographic examination of the accessory sex glands of boars

Thorough examinations of the reproductive system of boars are generally not performed on normal boars to be used for breeding; only boars with problems undergo a form of a breeding soundness examination. In order for veterinarians to identify pathological conditions, the normal architecture of the accessory sex glands needs to be described. The purpose of this study was to use B-mode ultrasonography to describe the accessory sex glands in the boar and to see if transrectal ultrasonography would be a viable option in which to obtain this data. Initially, cross-sectional saline bath examinations of accessory sex glands were performed on crossbred boar reproductive tracts (n = 4) using B-mode ultrasonography equipped with a 5 MHz dual frequency linear array transducer. In situ examinations were also performed on terminal line crossbred boars (n = 16) ranging in age from 10 to 23 months old using the same ultrasound methodology; four boars were under general anesthesia and the remaining 12 were standing in crates. Eight boars were abstinent for 2 days and the other eight had ejaculates collected 2 h prior to examination. The paired bulbourethral glands are best described as a long oval gland with a uniformly echogenic appearance with a large anechoic space in the center of the gland extending most of its length. The walls of the vesicular glands were found to be thin, with the parenchyma having multiple small echolucent areas that appeared to merge and form a central canal. The prostate gland was best identified as a pecan-sized gland with a uniform echogenic appearance. Visualization of the prostate gland was accomplished with more proficiency using the saline bath ultrasonography as compared to in situ examinations. All of the accessory sex glands could be examined using both methodologies of ultrasonographic examination with a 5 MHz frequency linear array transducer. It was determined that each accessory sex gland could be recognized, and differences between ejaculated and nonejaculated boars could be identified. The results of this study demonstrate that transrectal ultrasonography can be used as a diagnostic aid in assessing the accessory sex glands of boars.     

Seasonal changes in the fine structure of the accessory sex gland in the mole (Talpa europaea)

The mole has a single pair of accessory sex organs with features of both the prostate and the seminal vesicle, for which the term prostate gland is not appropriate. Seasonal changes occuring in this gland were related to four periods: a) the quiescence period, b) the maturation period, c) the active period and d) the involution period. During the quiescence period the cuboidal epithelial cells display a quasi-embryonic fine structure and are sparse in cytoplasmic organelles, but rich in glycogen and lipopigment. With the onset of sexual activity glycogen and lipopigment disappear and the rough endoplasmic reticulum as well as the Golgi apparatus begin to proliferate. The fully active gland is lined by a low epithelium with parallel stacks of rough endoplasmic reticulum, a large Golgi apparatus and several lysosomes and secretory granules. In the involution period the gland collapses and the epithelial cells are eliminated by hetero- and autophagic processes. During this period a great number of presumably endocrine cells were observed. The results were compared with findings in experimental studies and those on postnatal development of accessory sex glands in laboratory animals.