Accessory gland size influences time to sexual maturity and mating frequency in the stalk-eyed fly, Cyrtodiopsis dalmanni

Age at first reproduction is an extremely important life-historytrait. Several factors such as nutritional state and age-specificfecundity have been shown to influence time to sexual maturity;however, little work has been done in insects. We addressedthis in a stalk-eyed fly (Cyrtodiopsis dalmanni), by testingthe hypothesis that time to sexual maturity is associated withthe development of male internal reproductive structures. Wefound that sexual maturity was attained after an increased rateof growth in the accessory glands, several days after maturesperm bundles, and motile sperm were observed in the testes.Although testis development is essential, the results suggestthat accessory gland growth is more closely associated withthe time taken to reach sexual maturity than is testis growth.When we manipulated the growth of testes and accessory glandsvia a dietary manipulation, we found that delayed growth ratesincreased the time taken to reach sexual maturity. Among thedelayed individuals, sexually mature males had larger accessoryglands, but not testes, than did immature males. In adult males,mating frequency was significantly positively correlated withaccessory gland size, but not with testis length or body size.We conclude that accessory gland size is a critical determinantof sexual maturity and male mating frequency in this species.     

Morphology of the reproductive tract and acquisition of sexual maturity in males of Potamotrygon magdalenae (Elasmobranchii: Potamotrygonidae)

The purpose of this study was to describe the structure of the reproductive tract of males of Potamotrygon magdalenae before, during, and after they acquire sexual maturity, and to establish the first maturity scale for males within the family Potamotrygonidae. The male reproductive tract of P. magdalenae is composed of testes, efferent ducts, epididymides, deferent ducts, seminal vesicles, Leydig, alkaline, and clasper glands, and claspers, all of which are paired and functional. Four sexual maturity stages were established: immature, maturing, reproductively active, and resting. The degree of claspers calcification is also a good indicator of sexual maturity in this species. The testes are lobulated, each lobe contains numerous spermatocysts which are organized in zones and are displaced radially from germinal papillae to the spermatozoa zone where individual spermatozoa are conveyed to the efferent ducts. The epididymis can be regionalized in head, body, and tail; these regions are distinguished by external pigmentation and by the epithelium lining configuration. The tail of the epididymis is connected with the deferent duct and this, in turn, with the seminal vesicle. The spermatozoa are organized in spermatozeugmata which begin to form in the deferent duct; this latter organ is attached laterally at the Leydig gland that is composed by simple glandular units. Irregular and vesicular secretions can be found in the genital ducts. These secretions might be associated with the maturation of the spermatozoa and formation of spermatozeugmata. The male reproductive tract of P. magdalenae is similar to other elasmobranchs; however, two types of primary spermatogonia, an epididymis internally regionalized, and the presence and structure of spermatozeugmata are specific features not yet described in freshwater stingrays. Most of the year, the males were reproductively active, however, few resting adult males occurred during one of the months of the lowest waters. J. Morphol. 276:273–289, 2015. © 2014 Wiley Periodicals, Inc.     

Hermaphroditism in the lantern sharkEtmopterus unicolor (Squalidae,chondrichthyes)

Of the 70 specimens of the lantern shark,Etmopterus unicolor, collected in Suruga Bay and adjacent waters 22.9% were abnormal hermaphrodites, 30.0% normal males, and 47.1% normal females. Fifteen hermaphrodites had female reproductive organs composed of normal ovaries, oviducts, nidamentai glands and uteri as well as claspers. The clasper lengths of these hermaphrodites increased rapidly after the sharks reached 510 mm TL, the length about equal to the size at maturity for normal females. The ovary and uterus of abnormal females became mature at a total length greater than 500 mm, whereas the size at maturity was about 500 mm TL for normal females compared to 460 mm TL for normal males. In one specimen, the left gonad contained both ovarian and testicular tissues, the bulk of which was testicular.     

Using the composite variables of reproductive morphology, histology and steroid hormones to determine age and size at sexual maturity for the thorny skate Amblyraja radiata in the western Gulf of Maine

Age at size was linked to sexual maturity in 77 male and 93 female thorny skates Amblyraja radiata from the western Gulf of Maine using three criteria: 1) gross reproductive morphology, 2) histology and 3) steroid hormone concentrations. Age-bias plots and the coefficient of variation from vertebral band counts suggested that the ageing method represented a non-biased and precise approach to the age assessment of A. radiata . Maturity ogives for males, based on data gathered for clasper length, circulating testosterone concentrations and proportion of mature spermatocysts within the testes, predicted that 50% maturity occurred at a total length ( L _T) of 865 mm and c. 10·90 years of age. For females, maturity ogives, based on data gathered for ovary mass, shell gland mass, follicle size and circulating oestradiol concentrations, predicted that 50% maturity occurred at 875 mm L _T and c. 11·00 years of age. Collectively, the results suggest that analysis of several contemporaneous reproductive variables offers an accurate determination of sexual maturity in the thorny skate.     

The Relationship Between Oil Gland and Fruit Development in Washington Navel Orange (Citrus sinensis L. Osbeck)

Changes in structure, size and number of oil glands locatedin the fruit rind were assessed in developing fruit of the WashingtonNavel orange (Citrus sinensis L. Osbeck) from pre-anthesis tofruit maturity. Initiation of oil glands was found to be restrictedto early fruit development. Glands continued to develop throughoutfruit growth, until all reached maturity by a fruit size of30 to 50 mm diameter. Mature glands continued to enlarge withfruit growth. Mature fruit had between 8 000 and 12 000 oilglands. Anatomical studies of the fruit rind were carried outusing light microscopy on samples prepared by different tissueprocessing methods. Glands were found to develop from a clusterof cells adjacent to the fruit epidermis, into a structure consistingof a central cavity surrounded by several layers of epithelialcells. All glands were joined to the fruit epidermis, irrespectiveof their stage of development. Neither lignin nor suberin waspresent in the gland. Gland cavity formation appeared to involveschizogeny. Copyright 2001 Annals of Botany Company Washington Navel orange, Citrus sinensis L. Osbeck, fruit development, secretory cavity, oil gland, image analysis, light microscopy     

MORPHOGENESIS OF CAPITATE GLANDULAR HAIRS OF CANNABIS SATIVA (CANNABACEAE)

The glandular secretory system in Cannabis sativa L. (marihuana) consists of three types of capitate glandular hairs (termed bulbous, capitate-sessile, and capitate-stalked) distinguishable by their morphology, development, and physiology. These gland types occur together in greatest abundance and developmental complexity on the abaxial surface of bracts which ensheath the developing ovary. Bulbous and capitate-sessile glands are initiated on very young bract primordia and attain maturity during early stages of bract growth. Capitate-stalked glands are initiated later in bract growth and undergo development and maturation on medium, to full sized bracts. Glands are epidermal in origin and derived, with one exception, from a single epidermal initial. The capitate-stalked gland is the exception and is of special interest because it possesses a multicellular stalk secondarily derived from surrounding epidermal and subepidermal cells. Glands differentiate early in development into an upper secretory portion and a subtending auxiliary portion. The secretory portion, depending on gland type, may range from a few cells to a large, flattened multicellular disc of secretory cells. The secretory portion produces a membrane-bound resinous product which caps the secretory cells. Capitate-stalked glands are considered to be of particular evolutionary significance because they may represent a gland type secondarily derived from existing capitate-sessile glands.     

大仓鼠胁腺的发育及性别差异

通过对繁殖期雌雄大仓鼠胁腺重的比较研究发展雌雄鼠的胁腺重和体重分别存在正相关关系,非成年雌雄大仓鼠的胁腺重无显著性别差异,成年雄性大仓鼠的胁腺显著重于成年雌鼠,通过石蜡切片发现,雄鼠胁腺的皮脂细胞显著于雌鼠,对胁腺分泌物进行了气相色谱分析发现,雌雄胁腺分泌物的化学成分的种类和数量存在明显差异,本文从胁腺的形态,组织结构和化学成分三个方面初步揭示了胁腺在繁殖期具有性别别功能的机制。     

Ultrastructure of esophageal glands and their secretory granules in the root-knot nematodeMeloidogyne incognita

Summary The dorsal and subventral esophageal glands and their secretory granules in the root-knot nematodeMeloidogyne incognita changed during parasitism of plants. The subventral esophageal glands shrank and the dorsal gland enlarged with the onset of parasitism. While secretory granules formed by both types of glands were spherical, membrane-bound, and Golgi derived, the granules differed in morphology and size between the two types of glands. Subventral gland extensions in preparasitic second-stage juveniles were packed with secretory granules which varied in diameter from 700–1,100 nm and had a finely granular matrix. Within the matrix of each subventral gland granule was an electron-transparent core that contained minute spherical vesicles. The size and position of the core varied within different granules. Few granules were present in the dorsal gland extension in preparasitic juveniles. The matrix of dorsal gland secretory granules formed during parasitism was homogeneous and more electron-dense than the matrix of subventral gland granules. Subventral gland secretory granules of parasitic juveniles and adult females appeared degenerate.     

Novel reports of glands in Neotropical species of Indigofera L. (Leguminosae,Papilionoideae)

By considering controversial discussions in the literature with regard to gland denomination in Indigofera species, as well as the taxonomic value of secretory structures in Leguminosae, we aim to morphologically detail glands that had been previously observed in I. microcarpa and I. sabulicola, and to investigate the occurrence of glands in vegetative and reproductive organs of other six Neotropical species that belong to the genus. Glands analyzed through scanning electronic microscopy (SEM) in combination with anatomic analyses correspond to secretory trichomes that are classified into seven types. Main variations in relation to types occurred with regard to head shape and peduncle size. Trichome heads were multicellular, with a thin cuticle. Hollow heads with conspicuous inner space characterized only one type (type 1); the other trichome types had massive heads. Peduncles, which varied from biseriate to multiseriate, had thick, pecto-cellulosic cell walls. Trichomes were found on stems, stipules, petioles, rachis, petiolules, leaflets, bracteoles, sepals, standards and fruits, more commonly along the margins. Each of the eight Indigofera species analyzed had at least two different trichome types out of the seven types that occurred in reproductive and vegetative organs of these taxa. Various types of secretory trichomes were found in I. campestris, I. lespedezioides, I. microcarpa, I. spicata, I. suffruticosa and I. truxillensis. Stems and rachis were the vegetative organs in which a greater variety of trichomes occurred, and sepals were parts of reproductive organs with the same status. Five out of the seven secretory trichome types occurred on both vegetative and reproductive organs. Distribution and gland types differed between species and these gland distribution patterns can be used as diagnostic characters. Reports of glands in Indigofera campestris, I. hirsuta, I. lepedezioides, I. suffruticosa, I. spicata and I. truxillensis, their recognition as secretory trichomes, and the morphological variety of types found for such trichomes are novel data for Indigofera.     

Which proximate factor determines sexual size dimorphism in tiger snakes?

Diverse interactions between factors that influence body size complicate the identification of the primary determinants of sexual size dimorphism. Using data from a long‐term field study (1997–2009), we examined the contributions of the main proximate factors potentially influencing sexual size dimorphism from birth to adulthood in tiger snakes (Notechis scutatus). Data on body size, body mass and body condition of neonates, juveniles and adults were obtained by mark–recapture. Frequent recaptures allowed us to monitor reproductive status, diet and food intake, and to estimate survival and growth rates in age and sex classes. Additional data from females held briefly in captivity enabled us to assess reproductive output and the body mass lost at parturition (proxies for reproductive effort). From birth to maturity, individuals of both sexes experienced similar growth and mortality rates. We found no difference in diet, feeding and survival rates between the sexes, nor between juveniles and adults. On maturity, despite comparable diet and food intake by both sexes, the high energy requirements of vitellogenesis and gestation were responsible for a depletion of body reserves and probably resulted in a marked decrease in growth rates. Males were largely exempt from such costs of reproduction, and so could grow faster than females and attain larger body sizes. The absence of niche divergence between the sexes (uniformity of habitat, lack of predators) suggests that the impact of differential energetic investment for reproduction on growth rate is probably the main proximate factor influencing sexual size dimorphism in this species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 668–680.     

Reproduction and population aspects of the yellownose skate, Dipturus chilensis (Pisces, Elasmobranchii: Rajidae), from southern Chile

The total length (TL) at sexual maturity by sex, fecundity characteristics, and some population aspects (size structures and sexual proportions) are presented for the yellownose skate, Dipturus chilensis , in the eastern South Pacific Ocean. Samples were taken between January 2003 and August 2004 from three zones (principal fishing grounds for the species) in Chile's southern channels (41°30'S–55°10'S). TL at which 50% of the individuals reach maturity was significantly different by sex, with females estimated to mature at 103.9 cm and males at 89.7 cm. The average estimated fecundity was 23.4 (SD 6.4) ova per female. We report on the relationships of clasper lengths and oviducal gland widths with TL and the stages of maturity. Length compositions were statistically different by sex in the same zone (P < 0.05) and between zones for combined sexes (P < 0.05). The proportion of females increased when these reached the TL at which 50% attained maturity, becoming highly available to the fishing gear, possibly in relation to the reproductive strategy. Finally, the results yielded valuable knowledge about population responses to exploitation through fishing.     

Reproductive biology of the swell shark Cephaloscyllium ventriosum (Carcharhiniformes: Scyliorhinidae)

The Cephaloscyllium ventriosum shark is present in the artisanal fisheries of elasmobranchs on the western coast of Baja California Sur, Mexico. The main characteristics of the sexual maturation of this species based on individuals captured from off north-west Mexico in 2013–2016 are described. The size at maturity of this species was determined for the first time (total length 82 cm for females and 76 cm for males). Most females had one egg case per one uterus, and two per one uterus was an isolated event of low incidence. From the histological analysis of females, it was possible to show sperm storage in the oviducal gland. Fully developed sperm in immature organisms were identified in the testes. The main indicator of the maturity stage of males and their mating activity is the clasper. The present study provides evidence for a reliable estimation of the sexual maturity of these organisms, demonstrating the need for the combination of macroscopic and microscopic methods.     

The influence of the degree of infestation with trematode parthenites on the structure of penial glands in the mollusks Littorina saxatilis of different age

Histological and confocal microscopy studies of the structure of penial glands in the Littorina saxatilis males were carried out. The examined mollusks belong to two age groups and were at different stages of spontaneous infection with a trematode from the pygmaeus species group (Microphallus piriformes). Based on comparative analysis of microscopic sections of copulative organs in infested and non-infested mollusks, data on the modifications in histological structure ofpenial glands were obtained. From these data we can suggest that the infestation have an influence on all parts of the gland. Decrease of secret production and reduction of muscular capsule (down to its disappearance) were observed. We suppose that changes in the penial glands structure prevent their normal functioning. In the mollusks infested on reaching the sexual maturity, gradual reduction of distal part of reproductive system was observed, while in the mollusks infested before the sexual maturity, development of ancillary part of reproductive system was blocked.     

Active generation glands present in neonates of some Cordylid Lizards: A case study of Cordylus macropholis (Sauria: Cordylidae)

Generation glands are holocrine epidermal glands occurring on the ventral aspect of the thigh of cordylid lizards. In most species these glands seemingly start to differentiate with the onset of sexual maturity, but macroscopic signs of generation gland activity were noted in neonates of the large-scaled girdled lizard, Cordylus macropholis. The glands of neonatal, subadult, and adult individuals were examined microscopically using standard histological techniques. The glands of the five neonatal specimens examined, including both males and females, all had the same basic structure and displayed two layers of mature glandular material. In subadult and adult specimens, the number of layers varied from seven to nine. The structure of the generation glands of C. macropholis is similar to that of the few other Cordylus species that have been described to date. They are of the protruding kind with multiple mature glandular generations. Juveniles of an additional 12 cordylid species have been examined for the presence of active generation glands. Active glands were found to be present in neonates of C. tasmani and C. tropidosternum, both of which are, like C. macropholis, terrestrial species. In C. cordylus and C. coeruleopunctatus, active generation glands are absent in neonates, but differentiate soon after birth. In other cordylid species, generation glands apparently differentiate only with the onset of sexual maturity. J. Morphol. 235:177–182, 1998. © 1998 Wiley-Liss, Inc.     

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.     

Immunolocalization of venom metalloproteases in venom glands of adult and of newborn snakes of Bothrops jararaca

Using immunoelectronmicroscopy we analyzed qualitative and quantitatively the intracellular distribution of bothropasin, hemorrhagic factor 2 (HF2) and hemorrhagic factor 3 (HF3) in the venom secretory cells from adult snakes in the active (7 days after venom extraction) and in the resting (without venom extraction for 40 days) stages of protein synthesis. Glands from the newborn Bothrops jararaca were also studied. The results lead to the conclusion that all the secretory cells and the secretory pathway in the cells are qualitatively alike in regard to their content of the three metalloproteases. Secretory cells from the resting glands, unlike the active ones and the newborn glands, did not present immunolabeling in the narrow intracisternal spaces of the rough endoplasmic reticulum (RER). The label intensity for bothropasin was greater than that for the other proteins in the adults. HF3 and HF2 labeling densities in the newborn were higher than in the adults and HF3 labeling was not different from that of bothropasin. Co-localization of the three metalloproteases was detected in the RER cisternae of the active gland secretory cells, implying that mixing of the proteases before co-packaging into secretory vesicles occurs at the beginning of protein synthesis in the RER cisternae.     

Age and size at sexual maturity of the smooth skate Malacoraja senta from the western Gulf of Maine

Age and size at sexual maturity was determined for 185 male and 96 female smooth skates Malacoraja senta (ranging in size from 370 to 680 mm total length L_T), collected from the western Gulf of Maine. Maturity ogives for males, based on clasper length, testis mass and the proportion of mature spermatocysts in the testes, suggest that 50% maturity occurs between 9 and 10 years and 560 mm L_T. Maturity ogives for females, based on ovary mass, shell‐gland mass and maximum follicle size, suggest that 50% maturity occurs at age 9 years and 540 mm L_T.     

Sexual behaviour of immature male eastern mosquitofish: a way to measure intensity of intra-sexual selection?

Immature males of eastern mosquitofish Gambusia holbrooki start to be sexually active well before their copulatory organ (gonopodium) has completely developed and before they become able to transfer sperm. Sexual activity of males, consisting of copulatory attempts tending to bypass female acceptance, is intense (one attempt per minute) and is likely to be energetically very costly. The sexual behaviour of immature males relative to their maturation stage is described and tested against two possible adaptive explanations. Sexual activity was present in males from the beginning of the development of their gonopodium and increased during the following stages of maturation. Two to three weeks before gonopodium development was completed, sexual activity of immatures was as high as that of adults. Adult males showed aggressive behaviour against a male attempting a copulation, irrespective of the maturity of the latter. Since previous studies have shown that the reproductive success in this species is negatively correlated with male size when male–male competition is low (i.e. when the sex ratio is female biased), but decreases with male size when competition is high, the hypothesis was tested that sexual activity of immature males functions as a way to predict their future reproductive success if they mature at a given size. A second hypothesis tested was that precocious sexual experience improves the efficiency of copulatory attempts. Results were more in agreement with the first hypothesis, since size at maturity of males was influenced by the sex ratio experienced during maturation and precocious experience gave very little advantage.     

Size at the onset of sexual maturity in the anomuran crab, Aegla uruguayana (Aeglidae)

The size at maturity was studied in the crab Aegla uruguayana from the Areco River (31°14′ S, 59°28′ W), Argentina. Size at sexual maturity was determined according to three criteria: morphometric (change in the relative growth of reproductive characters), histological (first maturation of gonads) and functional (capability to mate and carry eggs). Regarding females, morphometric maturity occurred at a carapace length (CL) of 11.50 mm, considering abdomen width as a reproductive character. Gonad maturity of females could be observed at a minimum size ranging from 15 to 17 mm CL. The smallest ovigerous female observed in the field was 15.60 mm CL, although a relevant population incidence of ovigerous females (86.6%) has just been observed at values higher than 17 mm CL. As for males, the relative growth of the left chela length changed at a value of 15.40 mm CL, while morphological changes in sexual tube occurred between CL of 14 and 16 mm. Testicular maturation occurred at a CL ranging from 17 to 19 mm. The smallest size of males having spermatozoids in their vasa deferentia was 18.70 mm CL. The results obtained indicated that, in both sexes, functional maturity occurred after morphometric maturity and at a size similar to that of gonad maturity. Comparing sexes, females acquired sexual maturity (morphometric, gonad and functional maturity) at sizes statistically smaller than those of males.     

Development of secretory activity in the long hyaline gland of the male migratory grasshopper,Melanoplus sanguinipes (Fabr.) (Orthoptera : Acrididae)

Changes in the ultrastructure of epithelial cells from long hyaline glands of male Melanoplus sanguinipes (Fabr.) (Orthoptera : Acrididae) have been examined during sexual maturation and after allatectomy. In newly emerged males, the long hyaline gland epithelium is composed of 1–3 cell layers. The cells contain almost no rough endoplasmic reticulum, inconspicuous Golgi complexes, and large numbers of free ribosomes and polysomes. Within 24 hr, the cells undergo considerable reorganization to form a 1-cell-thick layer. Changes in cytostructure include proliferation of the rough endoplasmic reticulum and the development of several elaborate Golgi complexes. The developing lumen contains a coarse fibrous material. By 3 days postemergence, columnar epithelial cells are clearly capable of considerable synthesis and export of secretory protein. Rough endoplasmic reticulum, and large, elaborate Golgi complexes are the major structural features of the cytoplasm. From day 3 to sexual maturity (day 7), no major ultrastructural changes occur, although massive accumulation of secretion in the lumen causes the epithelium to become cuboidal or flattened. Isoelectric focusing of soluble proteins from long hyaline gland secretions shows that maturing glands contain increasing numbers and quantities of secretory proteins.Allatectomy has minor effects on long hyaline gland ultrastructure. A reduction in the density of rough endoplasmic reticulum and ribosomes suggests that glands from operated males are metabolically less active. This is confirmed by qualitative and quantitative changes in the amount of secretion as revealed by isoelectric focusing. The observations are discussed in terms of the juvenile hormone control of long hyaline gland maturation.