Testicular Follicles Research Articles

Paronatrema davidbowiei n. sp. (Trematoda: Syncoeliidae), a new parasite of the pelagic thresher (Alopias pelagicus) and its phylogenetic relationships within the suborder Hemiurata Skrjabin & Guschanskaja, 1954

A new species of hemiurid trematode found on the gills and in the aorta of the pelagic thresher Alopias pelagicus from the eastern Pacific, off Costa Rica, is described based on an integrative taxonomic approach that includes the use of light and scanning electron microscopy, and 28S rDNA sequencing. Phylogenetic analysis was also performed to explore, for the first time, the relationships of a member of the subfamily Otiotrematinae within the suborder Hemiurata. Paronatrema davidbowiei n. sp. can be distinguished from the congeners by having tegumental spines on the dorsal surface of the forebody, papillae on the oral sucker, and different morphology or number of testicular follicles. BLAST analysis revealed that sequences of Paronatrema davidbowiei n. sp. had the highest degree of similarity with Hirudinella spp. (Hirudinellidae). Results from Maximum Likelihood and Bayesian phylogenetic analyses, returning trees with the exact same topology and strong branch support, distinguished between the two superfamilies included in the suborder Hemiurata: Azygioidea and Hemiuroidea. Our analysis placed the new species in a clade with Copiatestes filiferus, the only existing sequence of the family Syncoeliidae.

Reduction in reproductive activity from degeneration of testicular follicles in Megapitaria squalida (Mollusca: Bivalvia) exposed to metal pollution in the Gulf of California

Over a reproductive cycle, the prevalence and intensity of degeneration of testicular follicles in Megapitaria squalida collected from the mining port of Santa Rosalia (a highly metal-polluted area), and San Lucas (a less polluted site), Gulf of California, Mexico, were evaluated. At San Lucas, most individuals had a typical testicular structure, and degeneration of testicular follicles was present in 9.5 % of spawning organisms. In contrast, at Santa Rosalia, 68 % of males, mainly in the ripe stage, had testicular degeneration (72 % severe intensity, mostly in medium and large-sized). Degeneration was characterized by intense hemocyte infiltration, identified as dense masses with numerous melanized cells in the follicle lumen. In both sites, males with testicular follicles degeneration had a lower condition index compared to males without degeneration. Degeneration of testicular follicles before spawning compromises and decreases the reproductive activity of M. squalida males at Santa Rosalia, which may ultimately affect the population sustainability.

Morphology of the male reproductive system and sperm of Leptoglossus zonatus (Dallas, 1852) (Heteroptera: Coreidae).

Taxonomic data on Coreidae have been fragmented over time and need to be revised. Likewise, data related to the development of germ cells and the features of the male reproductive system, including sperm, will contribute to understanding the biological mechanisms of reproduction and the systematics of its representatives. Aiming to provide these data, we describe the morphology of the male reproductive system and spermatozoa of Leptoglossus zonatus using light and transmission electron microscopies, respectively. Each of the two testes is surrounded by a bright red-pigmented sheath and formed by seven follicles arranged side by side. The two vasa deferentia are filled with individualized sperm, especially in their final portion, which is dilated and curved. After dilation, the vasa deferentia receive the ducts of the accessory glands of mesodermal origin. The other unpaired accessory gland is of ectodermal origin and opens into the ejaculatory duct. Both glandular types are densely coiled and have lumens filled with secreted material. Testicular follicles contain cysts with germ cells at different stages of spermatogenesis, indicating continuous production of gametes throughout adult life. Mature sperm measure around 310 μm long, with a nucleus of 36 μm and a flagellum formed only by an axoneme of 9 + 9 + 2 microtubules and two symmetrical mitochondrial derivatives. Like the sperm of other Heteroptera, the acrosome has a single structure (without perforatorium), there are no accessory bodies in the flagella, and the mitochondrial derivatives are connected to the axonemes, supporting the synapomorphic condition of these characteristics for this suborder of bedbugs. RESEARCH HIGHLIGHTS: The Leptoglossus zonatus sperm are slender and long, about 310 μm in length, and a nucleus 36 μm long. Spermatogenesis occurs throughout adult life and equally in the seven testicular follicles. The centriole adjunct in L. zonatus sperm does not give rise to accessory bodies. The ectodermal gland produces a filamentous secretion, whereas in the ectodermal sac, the secretion is globular.

Integrative taxonomy of Anaporrhutum mundae sp. nov. (Trematoda: Gorgoderidae), a parasite of the Munda round ray Urotrygon munda (Urotrygonidae) in Costa Rica.

A new species of trematode of anaporrhutine gorgoderid, from the gill chambers of the Munda round ray Urotrygon munda in Costa Rica is described, based on an integrative taxonomic approach that includes the use of light and scanning electron microscopy, ITS2 and 28S rDNA sequencing, and phylogenetic analysis. Anaporrhutum mundae sp. nov. can be distinguished from congeneric species by a combination of morphological traits and particularly by having the genital pore opening at the level of the intestinal bifurcation. The new species also can be distinguished from all other species of Anaporrhutum, except A. euzeti Curran, Blend & Overstreet, 2003, by having fewer testicular follicles per testis. Anaporrhutum mundae sp. nov. also differs from A. euzeti in its forebody shape and by having different morphology and location of the vitellaria. The study of the tegumental surface of A. mundae sp. nov., as revealed by scanning electron microscopy, allowed detection of new morphological characters for a member of Anaporrhutinae that may be of taxonomic value. These are: a stylet cavity dorsal to the oral sucker with a large penetration gland opening on each side of the cavity and small penetration gland openings located ventral to the stylet cavity, arranged in a circle around the mouth. This represents the first record of an Anaporrhutum species from Costa Rica. Further, A. mundae sp. nov. represents the first parasite described or reported in this host.

Morphological and ultrastructural studies of the internal reproductive systems of two deltocephaline leafhoppers, Nephotettixcincticeps and Deltocephalusvulgaris (Hemiptera, Cicadellidae, Deltocephalinae).

Insects have highly variable reproductive systems, reflecting a diversity of reproductive strategies and adaptations. Such variation has been widely used to classify and estimate phylogenetic relationships. Here, the morphology and ultrastructure of the internal reproductive systems of two leafhopper species are described and illustrated, using both light and transmission electron microscopy, and representing two tribes of Deltocephalinae: in Chiasmini, Nephotettixcincticeps (Uhler, 1896), and in Deltocephalini, Deltocephalusvulgaris (Dash & Viraktamath, 1998). Tables comparing the morphology of male and female internal reproductive structures of these studied species are provided and indicate that the main differences are in the relative shapes, sizes, and colors of these structures. The overall structure and organization, including details of the ultrastructure, of these two leafhopper species' male and female internal reproductive systems are very similar to those of previously studied leafhoppers. The main differences observed among species include the number of testicular follicles, the relative position of seminal vesicles and the degree of development of the accessory glands in the male, the number of ovaries, and the shape and color of the vagina and spermatheca in the female.

Eco-friendly postharvest irradiation strategy with 131I isotope for environmental management of populations of migratory locust, Locusta migratoria

Purpose Irradiation of food is promising for control of pests to minimize postharvest losses of yields and thus improvement of food safety, shelf life of produce. It is a method of choice that induces a series of lethal biochemical and molecular changes culminating into the engagement of a downstream cascade to cause abnormalities in irradiated pests. In this study, the effects of iodine-131 (131I) isotope radiation on the male gonad development of the migratory locust, Locusta migratoria, were evaluated. Materials and methods Newly emerged adult male locusts, less than one-day-old, were divided into two groups, control and irradiated. Locusts in the control group (n = 20 insects) didn’t drink irradiated water and were reared under normal environmental conditions for one week. Locusts in the irradiated group (n = 20 insects) were exposed to irradiated water at a dose of 30 mCi and they were subsequently observed until they drank the whole quantity. Results At the end of the experiment, scanning and electron microscopic examination of testes obtained from irradiated locusts revealed several major abnormalities, including malformed nuclei of spermatozoa, irregular plasma membranes, shrinkage of testicular follicles, vacuolated cytoplasm, disintegrated nebenkern and agglutinations of spermatids. Flow cytometry analysis revealed that 131I radiation induced both early and late apoptosis, but not necrosis, in testicular tissues. Testes of irradiated insects also exhibited a burst in reactive oxygen species (ROS), as indicated by significant elevation in amounts of malondialdehyde (MDA), a marker for peroxidation of lipids. In contrast, irradiation coincided with significant reductions in activities of enzymatic antioxidant biomarkers. Relative to controls, a three-fold upregulation of expression of mRNA of heat shock protein, Hsp90, was observed in testicular tissue of irradiated locusts. 131I-irradiated insects exhibited genotoxicity, as indicated by significant increases in various indicators of DNA damage by the comet assay, including tail length (7.80 ± 0.80 µm; p < .01), olive tail moment (40.37 ± 8.08; p < .01) and tail DNA intensity % (5.1 ± 0.51; p < .01), in testicular cells compared to the controls. Conclusion This is the first report on elucidation of I131-irradiation-mediated histopathological, biochemical and molecular mechanisms in gonads of male L. migratoria. Herein, the findings underscore the utility of 131I radiation as an eco-friendly postharvest strategy for management of insect pests and in particular for control of populations of L. migratoria.

Gonadal proliferation and reproductive cycle of the exotic sea squirt Cnemidocarpa amphora () (Pleurogona, Styelidae) sampled for the first time from the northern coast of Arabian Gulf in Saudi Arabia.

Specimens of Cnemidocarpa amphora were collected monthly from the Arabian Gulf from September 2017 to August 2018. Parts of their gonads were prepared for histological testing. The gonads' diameters varied by month. Each gonad contained many ovarian follicles with different morphologies and was surrounded by several testicular follicles. The ovarian and testicular follicles were separate, although the latter were always present near the former. Repeated measures ANOVA tests were conducted to investigate monthly changes in oocyte stages. In squirts measuring 12-13 cm in length, the gonads measured 30-50 mm from July to August; 20-25 mm from September to October; 15-20 mm from November to February; and 25-40 mm from March to June. Oogonia budded from the germinal epithelium with diameters of 20-30 µm. Previtellogenic oocytes measuring 70-120 µm were characterized by the deposition of small granules of protein around the nucleus, a continuous layer of follicular cuboidal epithelium, and scattered vacuoles in the ooplasm. The measurement of gonads and oocyte diameters were performed by image analysis (Image scope 2.3, Image Line, Inc.) and stage micrometer. The vitellogenic oocytes measured 130-220 µm and the follicular epithelium consisted of flattened and cuboidal layers. Beneath the vitelline membrane, scattered test cells appeared in the ooplasm and different granules of protein and MPS were deposited in the ooplasm. In the later phase, lipid droplets began to appear in the ooplasm. Yolk bodies formed after the impregnation of various granules together and the oocyte was ready to be shed. Before spawning, a yolk membrane appeared above the ooplasm. Post-vitellogenic oocytes, in which the homogeneity of ooplasm was restored, underwent gradual lysis and entered the atretic phase. Different stages of sperm development were present year-round in different follicles of the same squirt; hence, the testes were always mature.

A synopsis of the numbers of testicular follicles and ovarioles in true bugs (Heteroptera, Hemiptera) - sixty-five years of progress after J. Pendergrast's review.

The structure of testes and ovaries can be described in its simplest form by the number of follicles and ovarioles they contain. Sixty-five years after the last review of the internal reproductive systems in true bugs (Heteroptera), the data accumulated today on the number of testicular follicles and ovarioles in their gonads are summarized. In addition, data on the number and type (mesadenia/ectadenia) of accessory glands are given. The hemipteran suborder Heteroptera constitutes one of the most diverse groups of non-homometabolous ('Hemimetabola') insects, comprising more than 40,000 described species worldwide and approximately 100 families, classified into seven infraorders. Data are available for all infraorders; however, more than 90% of studied species belong to the largest and most evolutionarily derived infraorders Cimicomorpha and Pentatomomorpha. In true bugs, in general, the number of follicles varies from one to nine (in a testis), and the number of ovarioles varies from two to 24 (in an ovary). Seven follicles per testis and seven ovarioles per ovary prevail being found in approximately 43.5% (307 species) and 24.4% (367 species) of studied species, respectively. Such a structure of testes and ovaries is considered an ancestral character state in the Heteroptera. In the evolution of this group, the number of follicles and ovarioles both increased and decreased, but the trend towards a decrease clearly prevailed.

Notes of the internal adult male reproductive system of Pimelia subglobosa (Pallas, 1781) (Coleoptera: Tenebrionidae)

In the present study, the histoanatomy of the male reproductive organs was described for Pimelia subglobosa (Pallas, 1781) using light and scanning electron microscopy. Our study results revealed that the reproductive system in P. subglobosa consists of a pair of testes, vasa deferentia, seminal vesicles, two pairs of accessory glands (the first pair of glands is spiral shape and the second pair of glands is long-tubular shape), a ductus ejaculatorius and an aedeagus, all of which are described and illustrated. Each testis is made up of numerous oval testicular follicles. The testes resemble immature broccoli florets. The histo-anatomical examinations of testicular follicles showed that the growth, maturation and differentian zones contain various stages of spermatogenesis-spermiogenesis and could be divided into four stages depending on the shape and histological organization, which is divided into spermatogonia, spermatocytes, spermatids and spermatozoa. Sperm cells that are fully developed are transferred from testicular follicles to the vas deferens, which is in the form of a thin, long and convoluted duct. The seminal vesicle is a wide and sac-shaped structure into which the vas deferens enters. The first pair of accessory glands attach dorsally to the ejaculatory duct above the seminal vesicles. The wall of the second pair of accessory glands is very thin and located just above the first accessory gland. The ductus ejaculatorius connects the other parts of reproductive organs to the aedeagus. The aim of this paper is to summarize current state of knowledge of the male reproductive organs in P. subglobosa. These data are discussed in comparison with the male reproductive system in other coleopteran species.

The association of the development of the internal reproductive organs of male desert locusts, Schistocerca gregaria (Orthoptera: Acrididae), with age, phase and the effect of exposure to pheromones

The regulation of the development of the male reproductive organs in insects is still an open question. Although the desert locust, Schistocerca gregaria, has been extensively examined, there is little information on the effects of phase and pheromones on the development of the male reproductive organs. This study clarified the association of these two factors with reproductive development (length or width of each organ) of the testis, testicular follicles, accessory glands, and seminal vesicles in this locust. The width of the follicles and width and length of the accessory gland mass are significantly associated with phase (solitary or gregarious). Developmen of all reproductive organs is age dependent as these organs developed in the adult stage. The development of follicles and accessory glands (width) in males in the first two weeks of adulthood was promoted by exposing them to pheromones from mature adults, but not from nymphs. These results indicate the incidence of male reproductive development is associated with phase and affected by pheromones.

Impact of substerilizing dose on histological changes in gonads and ovaries of Ephestia cautella (Lepidoptera: Pyralidae) by gamma radiation

To investigate the effect of Gamma radiation on the reproductive systems of emerged female and male of Ephestia cautella (Walker) moths, mature pupae of both sexes were irradiated with doses of 50, 100 and 150 Gy. Histological study of the treated individuals showed in females that the ovaries appear sever damage in the follicular epithelium at all doses, which become thinness and separated from developing oocytes, moreover, some of the nurse cells were rupture. In males which treated with 150 Gy, it was noticed retardation in the stages of spermatogenesis and few numbers of sperm bundles and their dispersion in the testicular follicles’ adults, on the other hand, the doses of 50 and 100 Gy showed little or moderate effects on the structure of the testis contents.

Testes morphology and the identification of transcripts of the hormonal pathways of the velvetbean caterpillar Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae)

Anticarsia gemmatalis is one of the main defoliating pests of soybeans in Brazil. In the current study, we characterized the histomorphology of the testes and the spermatogenesis process in A. gemmatalis. We also identified transcripts involved in the biosynthesis, metabolism, and signaling of juvenile and ecdysteroid hormones, in order to provide information about potential mechanisms of regulation of hormonal pathways in this species. Our analyses revealed that the A. gemmatalis larvae have a pair of kidney-shaped testicles. These are divided into four testicular follicles, where there are germ cell cysts at different stages of development. In the pupal stage, the testicles are fused, so adults have a single spherical testis, with a variable number of follicles. The A. gemmatalis has centripetal spermatogenesis and exhibits spermatic dimorphism. We identified 31 transcripts that encode proteins involved in juvenile hormone and ecdysteroid pathways, such as mevalonate kinase, CYP14A1, ecdysone receptor, among others. Our results on the morphology of the testes and spermatogenesis process, as well as identification of the genes involved in hormonal pathways in A. gemmatalis, provide important data for understanding the biology of this agricultural pest, which can be used as a basis for further research in other economically important lepidopterans.

Comparative aspects of the internal reproductive system of males in species of Melolonthinae, Dynastinae, and Rutelinae (Coleoptera: Scarabaeoidea) from Mexico

The anatomy of the internal male reproductive systems of 12 species of Melolonthinae (Phyllophaga, Chlaenobia, Macrodactylus, Isonychus), six species of Dynastinae (Cyclocephala), and three species of Rutelinae (Paranomala) (Coleoptera, Scarabaeoidea) of Mexico are described. A total of 350 male specimens representing 21 species were collected. From each species, the reproductive systems were obtained by micro-dissection, placed in a liquid fixative, stained, and drawn to scale. The internal genitalia of each species was described and compared among the species examined. The reproductive system of the Melolonthinae species is comprised of two testicles, each with six follicles, two deferent ducts, two accessory glands, two glandular ducts, an ejaculatory duct, and the aedeagus (not described for any of the species examined). The number of testicular follicles per testicle is as reported in different species of other Scarabaeoidea subfamilies. The length of the accessory glands and the ejaculatory duct varies in the species studied. The ejaculatory bulb is present in all of the species of Dynastinae and Rutelinae examined but in only three species of Melolonthinae.

Structural and histological observations on the male reproductive system of adult red poplar leaf beetle Chrysomela populi Linnaeus, 1758 (Coleoptera: Chrysomelidae).

This study described the anatomy and histology of the male reproductive system in Chrysomela populi, which is an economically important species belonging to the family Chrysomelidae. Therefore, reproductive biology has been studied to combat this insect. As well as, the characters associated with the reproductive tract have been potential to discuss aspects of the system and to better understand the reproductive dynamics. The male reproductive system of C. populi has a pair of testes, a pair of vas efferentia and deferentia, a pair of seminal vesicles, a pair of accessory glands, an ejaculatory bulb, an ejaculatory duct, and an aedeagus. The testis consists of two flower-shaped lobes. Each testis has 20 sperm tubules (testicular follicles) containing cysts of germ cells at various developmental stages within the light orange peritoneal sheath. Testicular follicles are composed of three different (growth, maturation, and differentiation) zones. In the middle region of each testis joins with the vas efferens. The testis is attached to the seminal vesicle by a small stalk like vas efferens. In the lumen of the vas efferens, seminal vesicle, and vas deferens, sperms form clumps in the form of thin threads. The proximal end of the vas deferens is connected to the common ejaculatory duct. It joins with the ejaculatory bulb. Around the ejaculator bulb, there is a pair of convoluted, flat-surface tubular structure accessory glands. Posterior ejaculatory duct joins with the aedeagus.

Anatomy and histology of the male reproductive tractof Machtima crucigera (Fabricius, 1775) (Heteroptera: Coreidae)

Representatives of the Coreidae, include species of economic importance that are pests in some crops, such as Machtima crucigera (Fabricius, 1775) pest of acerola crops. Morphological studies can contribute to the understanding of the evolutionary history of insects and to elucidate their reproductive strategies. This study describes the structure of the male reproductive tract of this insect. The males have two pectin-shaped testes, with seven follicles each, and many cysts at different developmental stages. In the testicular follicles, three spermatogenesis regions are recognized: the growth, maturation and differentiation zones. The reproductive tract also includes a pair of deferent ducts, each which enlarge into two seminal vesicle, accessory glands of mesodermal and ectodermal origins, an ejaculatory bulb, an ectodermal sac and an ejaculatory duct ending in the aedeagus. The testes and seminal vesicles are covered externally by an orange-pigmented peritoneal sheath. The morphological features of the male reproductive tract of M. crucigera and its similarities with other Heteroptera are discussed. These characters have potential to elucidate reproductive strategies of this agricultural pest and the evolutionary history of the group.

Anatomical and histochemical descriptions of the male reproductive system of Diachasmimorpha longicaudata (Ashmed) (Hymenoptera: Braconidae)

ABSTRACT The parasitoid Diachasmimorpha longicaudata is an important control agent for several species of fruit flies. Research on the characteristics of the reproductive system and reproductive biology of this parasitoid can be valuable for studies in taxonomy and phylogeny of insects of the order Hymenoptera. In this study we analyzed the histology and histochemistry of the male reproductive system of D. longicaudata. In this species the male reproductive system consists of a pair of testes, two accessory glands, and an ejaculatory duct. Each testicle consists of only one follicle. The testicular follicles are filled with cysts in different stages of spermatogenesis. Histochemical analyses detected proteins and carbohydrates in the cytoplasm of secretory cells and in the lumen of accessory glands. The morphology of the male reproductive system of D. longicaudata differs in some respects from other species of Hymenoptera.

Morphology of the male reproductive tract in the water scavenger beetle Tropisternus collaris Fabricius, 1775 (Coleoptera: Hydrophilidae)

ABSTRACT Members of the Hydrophilidae, one of the largest families of aquatic insects, are potential models for the biomonitoring of freshwater habitats and global climate change. In this study, we describe the morphology of the male reproductive tract in the water scavenger beetle Tropisternus collaris. The reproductive tract in sexually mature males comprised a pair of testes, each with at least 30 follicles, vasa efferentia, vasa deferentia, seminal vesicles, two pairs of accessory glands (a bean-shaped pair and a tubular pair with a forked end), and an ejaculatory duct. Characters such as the number of testicular follicles and accessory glands, as well as their shape, origin, and type of secretion, differ between Coleoptera taxa and have potential to help elucidate reproductive strategies and the evolutionary history of the group.

Estructura histológica del sistema reproductor masculino de la cigarrita Aethalium reticulatum (Hemiptera: Aethalionidae)

Para ampliar el conocimiento sobre la biología reproductiva del grupo de los hemípteros Auchenorrhyncha, en este trabajo se describe la histología del sistema reproductor masculino de Aethalio reticulatum. Alcance. Las cigarritas de la familia Aetahalionidae son insectos terrestres y predominantemente fitófagos, que se configuran como plagas agrícolas cuando se encuentran en altas densidades de población. El conocimiento de la biología reproductiva de estos insectos genera caracteres que pueden proporcionar información clave para futuros trabajos relacionados con la evolución, el comportamiento y las estrategias de control de plagas. Metodología. Las muestras de los insectos se recolectaron del arbusto Trema micrantha y para estudiar la anatomía reproductiva de A. reticulatum se utilizaron técnicas de microscopía óptica. Principales resultados. La anatomía del sistema reproductivo interno en los machos está compuesta por un par de testículos, cada uno de los cuales contiene cuatro folículos, vesículas seminales, conductos deferentes, glándulas accesorias y un conducto eyaculador. Los folículos testiculares tienen células en diferentes etapas de desarrollo. Los espermatozoides salen de los testículos en paquetes y se deshacen cuando alcanzan las vesículas seminales. En cada quiste en promedio se encontraron 649 espermatozoides. Las glándulas accesorias secretan diferentes tipos de gránulos de secreción. El conducto eyaculador tiene una cutícula que muestra su origen ectodérmico. Conclusión. Se describe por primera vez la histología del sistema reproductivo de la familia Aethalionidae, generando información que aumenta el conocimiento sobre su biología y que se puede utilizar en el sistema Auchenorrhyncha y en futuras estrategias de control para esta importante plaga agrícola.

Morphology and histology of the male reproductive system of Collaria oleosa (Distant, 1883) (Heteroptera: Miridae)

Collaria oleosa (Distant, 1883) is a phytophagous bug often observed causing injuries in wheat, barley, and oat crops, besides grass pastures. The male reproductive system of C. oleosa has been studied anatomically and histologically. It consists of a pair of testes, each one with two follicles, one pair of seminal vesicles, two pairs of external accessory glands, and an ejaculatory bulb. The testicular follicles exhibit cysts with spermatogonia, spermatocytes, spermatids, and spermatozoa bundles. The testes are connected to the seminal vesicles by the vas deferens. The seminal vesicles are connected to the ejaculatory bulb and are bound by the accessory glands. In mirids belonging to the Stenodemini tribe, the general morphology of the male reproductive system is similar. However, two follicles per testis may be characteristic of the genus Collaria. The anatomy and histology of the male reproductive system in C. oleosa provides new information and also contributes to the understanding of the systematics of Stenodemini as well as the Miridae family in general.

Vasa deferentia and associated structures of the male Panorpodes kuandianensis (Mecoptera: Panorpodidae)

The male reproductive system may provide significant evidence for the taxonomic and phylogenetic analyses of insects. However, current knowledge of the male reproductive system in Mecoptera is mainly concentrated on the external genitalia, and is rarely involved in the internal reproductive system. Here, we investigated the morphology and the fine structure of the vasa deferentia and associated structures of the male reproductive system of Panorpodes kuandianensis Zhong et al., 2011 (Panorpodidae) using light, scanning, and transmission electron microscopy. The male reproductive system of P. kuandianensis consists of a pair of symmetrical testes with three tubular testicular follicles, two epididymides, two distinctly partitioned vasa deferentia, a pair of mesadenia, one ejaculatory sac, and the external genitalia. A pair of expanded seminal vesicles are modified from the median part of the vasa deferentia, and evolve into secretory organs. The seminal vesicles have elongated cylindrical epithelial cells, which contain abundant secretory materials in the cytoplasm and form a small central lumen, likely serving a secretory function rather than provisionally storing sperm as in most other insects. Alternatively, the sperm are stored temporarily in the epididymis, the greatly coiled portion of the vasa deferentia. The morphology of the male reproductive system supports the close relationships of Panorpidae and Panorpodidae.