Rapid and efficient mating in mayflies (Ephemeroptera): morphological and reproductive strategies in primitive winged insects.

Mayflies (order Ephemeroptera) are primitive winged insects with a life cycle of aquatic nymphal development until emergence as adults that briefly fly seeking mates. Mayflies have reproductive morphology and strategies promoting efficient copulation and oviposition during the ephemeral terrestrial phase. The anatomy of the reproductive tract in males and females of Thraulodes latinus (Leptophlebiidae) is described in relation to the reproductive behavior of Ephemeroptera. Males have a pair of testes that are degenerate in the preadult life stage (subimago) and a pair of deferent ducts that open directly into the gonopores, without ejaculatory duct and accessory glands that are common in other insects. Adult females have a pair of pectinate ovaries with many mature oocytes, a pair of lateral oviducts, and a common oviduct, but lack spermatheca for storage of sperm and associated glands as in most insects. During mating, the paired deferent ducts of males inject sperm directly into females' lateral oviducts, where mass fertilization occurs. Contraction of the intrinsic muscles of the male's deferent ducts directs and rapidly propels the flow of spermatozoa. Reproductive strategies, such as facultative parthenogenesis in mayflies and associated selective pressures involved in the morphology and reproductive behavior of these insects, are discussed.

A new species of Thraulodes Ulmer (Ephemeroptera: Leptophlebiidae), with additional data on the anatomy of the reproductive tract

ABSTRACT A new species of Thraulodes Ulmer 1920 is described based on nymphs and imagos from Tapias river, Caldas department, Colombia. The mature nymphs were reared until the emergence of the imagos. Thraulodes latinus sp. n. can be distinguished from other species of the genus by: In males, the forewing without cross veins basal to bullae and with 11-14 cross veins distal to bullae, abdominal and legs color pattern, styliger plate redounded, with a long and digitiform median projection and shape of penes with apicolateral area forming an "ear-like" projection. In nymphs, the claws with eight denticles and the general coloration pattern. Additionally, data on the anatomy of the reproductive tract of both the male and female imago of the new species are presented.

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.

Tricorythopsis nupem: a new species for the Atlantic forest from southeast Brazil (Ephemeroptera: Leptohyphidae).

Tricorythopsis Traver, 1958 is a neotropical genus of the Leptohyphidae (Ephemeroptera, Ephemerelloidea), with 19 species described (Molineri 2001; Dias Salles 2005; Dias et al. 2008, 2009; Lima et al. 2011; Belmont et al. 2011, 2012, 2015; Domínguez et al. 2019). The genus comprises species of approximately two or three millimeters, and can be considered one of the smallest members of the order (Molineri 1999, 2001; Dias Salles 2005; Dias et al. 2006, 2008, 2009; Belmont et al. 2011, 2015).

Anatomy of male and female reproductive organs of stink bugs pests (Pentatomidae: Heteroptera) from soybean and rice crops / Anatomia dos órgãos reprodutivos em machos e fêmeas de percevejos praga (Pentatomidae: Heteroptera) das culturas de soja e arroz

Abstract: Pentatomidae comprises a diverse group of stink bugs widely distributed in the Neotropical region. Many species are phytophagous and cause injuries to plants, and can thus be defined as agricultural pests. In this study, the anatomy of the female and male reproductive tracts of three important agricultural pests in Colombia is described: Piezodorus guildinii Westwood, 1837 and Chinavia ubicaRolston 1983, found on soybeans, and Oebalus insularis Stål, 1872, found in rice crops. For that, light microscopy techniques were used. The anatomy of the reproductive tract of sexually mature males of the three species studied consisted of a pair of testes, vas deferens, seminal vesicles, ejaculatory bulb, an ejaculatory duct that opens into an aedeagus, and paired accessory glands. The reproductive tract of females consisted of a pair of ovaries, each with seven telotrophic-meroistic ovarioles, a pair of lateral oviducts, common oviduct, spermatheca, and a genital chamber. Telotrophic ovarioles were comprised of terminal filament, tropharium, vitellarium, and pedicel. Differences in size, color, and position of structures along the reproductive tract were observed between the species examined. Reproductive biology of insects provides informative characters for behavioral and evolutionary studies, as well as useful data for pest control strategies.

Resumo: Pentatomidae compreende um diverso grupo de percevejos amplamente distribuídos na região Neotropical. Muitas espécies são fitófagas e causam algum tipo de injúria em plantas, podendo se configurar como pragas agrícolas. Neste trabalho, descrevemos a anatomia do trato reprodutor de machos e fêmeas em três importantes pragas agrícolas da Colômbia: Piezodorus guildinii (Westwood 1837) e Chinavia ubica (Rolston 1983) na cultura de soja e Oebalus insularis (Stål 1872) na cultura do arroz. Para isto, foram utilizadas técnicas de microscopia de luz. A anatomia do trato reprodutor em machos sexualmente maduros nas três espécies consistiu de um par testículos, vasos deferentes, vesículas seminais, bulbo ejaculatório, um ducto ejaculatório que se abre em um aedeagus e glândulas acessórias pareadas. O trato reprodutor das fêmeas consistiu de um par de ovários, cada um com sete ovaríolos telotróficos-meroísticos, um par de ovidutos laterais, uma espermateca e a câmara genital. Os ovaríolos telotróficos possuíam quatro diferentes regiões: filamento terminal, germário, vitelário e pedicelo. As diferenças entre as espécies foram observadas no tamanho, cor e posição das estruturas ao logo do trato reprodutivo. A biologia reprodutiva de insetos gera caracteres que fornecem informações para trabalhos envolvendo evolução, comportamento e estratégias de controle de pragas.

Sperm storage in Hemidactylus mabouia: Morphological and ultrastructural aspects of a reproductive strategy.

Sperm storage is a common phenomenon in most female reptiles. Evidence of sperm storage is based on the observation that female fertilization occurs even when females are separated from males, as well as the presence of agglomerates of spermatozoa in specific regions of the oviducts. Lizards are capable of storing sperm in the uterine tube, vagina, or in both regions. However, representatives of the Gekkonidae family commonly store spermatozoa in the uterine tube, which is considered an ancestral character state for Squamates. Using comparative techniques of light, transmission and scanning electron microscopy, we observed stored sperm organized in compact bundles with their heads facing the bottom of the crypts of the uterine tube, indicating chemotactic attraction. The alignment and packing of spermatozoa in Hemidactylus mabouia indicates that the process of evacuation of the crypts for fertilization may be related to the passage of the egg that exerts mechanical pressure against the walls of the uterine tube, causing its distension and the release of spermatozoa. We conclude that the sperm storage region and the morphological organization of the crypts in the uterine tube of H. mabouia is similar to other previously studied species of lizards, supporting the notion that sperm storage is a common reproductive strategy among female reptiles.

Ultrastructure of spermatozoa in two solitary bee species with an emphasis on synapomorphic traits shared in the family apidae.

Morphology of spermatozoa in bees has provided promising results for phylogenetic analyses. In this work, the structure and ultrastructure of spermatozoa from Thygater (Thygater) analis and Melitoma segmentaria were characterized and the synapomorphies shared in the family Apidae are discussed. In these species, spermatozoa bundles which are undone in the seminal vesicle possess, on average, 50 cells. Spermatozoa consist of a head and a flagellar region. The head includes an acrosome containing the perforatorium, covered by the acrosomal vesicle and a nucleus. The flagellum is formed by two mitochondrial derivatives, which are asymmetric in diameter and length, with one centriolar adjunct, one axoneme (9 + 9 + 2), and two accessory bodies. In cross section the centriolar adjunct is asymmetric and the accessory bodies are triangular in shape. In the distal region of the flagellum, the derivative terminates before the axoneme and the small derivative terminates first. The axoneme is gradually disorganized and the accessories microtubules are the last to terminate. In these two species, spermatozoa share diverse synapomorphies with those of other bee species previously described in the literature, which allows for the establishment of a morphological pattern for spermatozoa of the family Apidae.

Morphological aspects of testes and sperm ultrastructure in the "symphyta" Digelasinus diversipes kirby 1882 (hymenoptera: Argidae: Dielocerinae).

In Digelasinus diversipes, spermatozoa are maintained in bundles, with 74 spermatozoa on average, in the seminal vesicle. These spermatozoa are very short (20 µm) and consist of a head and flagellum. The head includes an acrosome (perforatorium covered by the acrosomal vesicle) and a nucleus. A regular electron-lucent region separates the acrosomal vesicle from the perforatorium, which is inserted parallel to the anterior ending of the nucleus. The small flagellum is composed of two symmetrical mitochondrial derivatives, a centriolar adjunct, an axoneme (9 + 9 + 2), and two accessory bodies. The centriolar adjunct begins above the posterior end of the nucleus and ends covering the anterior tip of two mitochondrial derivatives. In the terminal region of the axoneme, the central microtubules terminate first. The presence of a subacrosomal space, a short mitochondrial derivative diameter, and a short spermatodesm is the ultrastructure characteristics of spermatozoa shared by all "symphyta" species. Differences in the insertion of the perforatorium into the nucleus and the position of the centriolar adjunct distinguish Dielocerinae and the Arginae studied previously. The number of spermatozoa per cyst is variable. Furthermore, additional characteristics that had not been described for "symphyta" were also found, such as the number of follicles per testis.

Oviductal structure and ultrastructure of the oviparous gecko, Hemidactylus mabouia (Moreau De Jonnès, 1818).

Lizards of the family Gekkonidae display a variety of reproductive patterns, as evidenced by the presence of viviparous and oviparous species. The species Hemidactylus mabouia is oviparous. We examined, in vitellogenic females, oviductal structure by light microscopy after routine histological and histochemical techniques, as well as by scanning and transmission electron microscopy. The oviduct is composed of four different regions: the infundibulum, which opens into the coelomic cavity and receives the oocyte released at the time of ovulation; the uterine tube, where sperm storage takes place; the uterus, which is responsible for the eggshell production; and the vagina, the final portion of the oviduct that leads to the cloaca. The oviductal structure of H. mabouia is similar to that of other oviparous lizard species and can be useful for morphological comparative analysis among reptile species.

Ultrastructure and heteromorphism of spermatozoa in five species of bugs (Pentatomidae: Heteroptera).

Pentatomidae is one of the largest Heteroptera families, comprising about 10% of the species estimated for the suborder. In spite of existing studies, doubts remain regarding the systematics of Pentatomomorpha. In this study, five species of Pentatomidae spermatozoa were examined to achieve characteristics that enable inferences in the phylogeny of the group and in behavioral issues associated with the presence of polymorphisms. Spermatozoa polymorphisms, characterized by two classes of sizes, are found in Podisus nigrispinus, Podisus distinctus, and Brontocoris tabidus, whereas Thynacanta marginata (Dallas) and Supputius cincticeps have single-size spermatozoa. The head region consists of an acrosome, a nucleus, and part of the centriolar adjunct. In the more anterior region, the nucleus is parallel to the centriolar adjunct. In the nucleus-flagellum transition region, the nucleus overlaps the anterior region of the mitochondrial derivatives, just above the axoneme. The mitochondrial derivatives and the axoneme run the entire extent of the flagellum. In species in which the spermatozoa are polymorphic, the larger spermatozoa have derivatives mitochondrial approximately 3-fold larger than the smaller spermatozoa. Characteristics derived from the morphology of spermatozoa indicate synapomorphies and are promising for systematic studies.

Phagocytosis of spermatozoa by epithelial cells in the vagina of the lizard Hemidactylus mabouia (Reptilia, Squamata).

Hemidactylus mabouia is an Africa oviparous lizard that is now distributed on other continents and has been introduced to Brazil. In the majority of reptiles, the females have the ability to store spermatozoa in specialized regions of the genital tract. Considering that in H. mabouia the storage of spermatozoa is restricted to the region of the uterine tube, in this study we utilized optical and transmission electron microscopy to investigate the processes related to the large number of spermatozoa in the vagina. Although it was possible to visualize spermatozoa in the vagina, an ultrastructural analysis of the region revealed that significant phagocytosis occurs, which is mediated by the epithelial cells. Such a process indicates that the anterior portion of the vagina is related to the elimination of supernumerary or deficient spermatozoa and not storage.

Morphology of the male reproductive system of the social wasp, Polistes versicolor versicolor, with phylogenetic implications.

Variation in the morphology of the adult male reproductive system among different groups of Hymenoptera offer characteristics that help studies of behavior and the evolutionary history of this group. The objective of this study was to describe the adult male reproductive system of the wasp Polistes versicolor versicolor Olivier (Vespidae: Polistini). The reproductive systems were dissected, fixed and embedded for light microscopy. In P. v. versicolor, the reproductive system includes a pair of testes, each one with three fusiform follicles. From each follicle emerges an efferent duct that later join together, forming a deferent duct. The first half of the deferent duct is enlarged and differentiated into a region specialized for sperm storage, the seminal vesicle. At the post-vesicular region of each of the deferent ducts an accessory gland emerges. The seminal vesicle and the accessory gland are covered with a capsule forming a vesicle-gland complex, also observed in some species of North American Polistes. Sperm are released from testes in bundles, which are disorganized inside seminal vesicles. In the testicular follicles, 95 spermatozoa were observed per cyst on average.

Ultrastructural characterization of the spermatozoa of Aethalion reticulatum Linnaeus 1767 (Hemiptera: Auchenorrhyncha: Aethalionidae).

The Hemiptera order is currently divided into four suborders. Among them the Auchenorrhyncha suborder is considered to be paraphyletic. Morphology of insect spermatozoa has provided promising characteristics that can be used for phylogenetic inference. In this study, Aethalion reticulatum (Aethalionidae) spermatozoa were examined by light and electron microscopy. The head of the spermatozoa is composed of an acrosome and a nucleus. The nucleus is linear and filled with compact chromatin but has electron-lucid spaces. The centriole adjunct initiates parallel to the nucleus and terminates in the region anterior to the mitochondrial derivatives. Flagella consist of an axoneme, two mitochondrial derivatives and two accessory bodies and the axoneme has the typical 9+9+2 microtubule pattern. The mitochondrial derivatives are symmetric. The accessory bodies are long and are shaped like a half moon when viewed from a cross-section. The presence of accessory bodies differs from other species of Cicadomorpha previously studied. Spermatozoa morphology of other Auchenorrhyncha families can reveal synapomorphies and contribute to systematics of the suborder.

Structural and ultrastructural characteristics of male reproductive tract and spermatozoa in two Cryptinae species (Hymenoptera: Ichneumonidae).

This study represents the first characterization of male reproductive tracts and ultrastructural description of sperm of Cryptinae species. In Lymeon dieloceri and Pachysomoides sp., the male reproductive tract is formed by a pair of testis, two deferent ducts, two accessory glands and one ejaculatory duct. The spermatozoa are similar to those described for other Hymenoptera, with: (1) the acrosome formed by the acrosomal vesicle covering the perforatorium, which has its base inserted in a cavity located in the nucleus point; (2) a thin nucleus with electron-dense chromatin; (3) an electron-dense centriolar adjunct located between the nucleus and one of the two mitochondrial derivatives; (4) an axoneme with a 9 + 9 + 2 microtubule arrangement; (5) two long mitochondrial derivatives with peripheral cristae and; (6) two accessory bodies located between the two mitochondrial derivatives and the axoneme. These ichneumonids present structural characteristics similar to other parasitic wasps, such as presence of a single follicle per testis, layer of extracellular material enveloping the acrosome and accessory microtubules ending before others in final portion of the flagellum. However, male reproductive system and the spermatozoa presented morphological characteristics that allowed their differentiation, such as oval shapes accessory glands and the symmetric mitochondrial derivatives in L. dieloceri compared to the spherical accessory glands and asymmetrical derivatives observed in Pachysomoides sp. Taken together, data presented here demonstrates that diversity of morphological characteristic from the male reproductive tract and spermatozoa in Hymenoptera might provide a character system that can be used, in association with other systems, to resolve various uncertainties about the evolutionary relationships of this insect group.

Structure and ultrastructure of the spermatozoa of Trypoxylon (Trypargilum) albitarse Fabricius 1804 (Hymenoptera: Apoidea: Crabronidae).

The ultrastructure of the spermatozoa of Trypoxylon (Trypargilum) albitarse is described here for the first time within this genus. Testes and seminal vesicles were dissected and processed for transmission electron microscopy. In the testicular follicles, the spermatids are arranged in a maximum number of 32 for each cyst. The spermatozoa are slender and they measure approximately 150 microm in length. The head is about 17 microm long and is formed by the acrosome and the nucleus. The flagellum consists in an axoneme, two mitochondrial derivatives, two accessory bodies and, at the nucleus-flagellum transition, a symmetric centriolar adjunct. The axoneme presents the typical 9+9+2 microtubule pattern. In the terminal region, the central microtubules and nine doublets finish first, followed by the accessory microtubules. Both mitochondrial derivatives begin together and are inserted in the base of the centriolar adjunct. Along the middle region, the larger derivative has almost twice the area of the smaller one and includes a discrete paracrystalline region. At the tip, the smaller derivative ends before the larger one and both before the axoneme. The characters derived from the ultrastructure of the spermatozoa of T. albitarse show synapomorphies shared with the Apoidea and present characters that are probably apomorphic for the Crabroninae subfamily.

Ultrastructural, histological and histochemical characteristics of the epithelial wall of the seminal vesicle of mature Scaptotrigona xanthotricha moure males (Hymenoptera, apidae, meliponini)

The seminal vesicles of mature Scaptotrigona xanthotricha males were investigated using light microscopy, histochemistry and transmission electron microscopy. The globular seminal vesicles were ~450 ìm in diameter and consisted of a sperm-filled lumen and a single layer of epithelium surrounded externally by a muscular sheath. The mitochondria-rich epithelial cells had many inclusions in the basal region. These inclusions were relatively large and contained membranous structures similar to myelin figures. The epithelial cells of the seminal vesicle showed none of the features characteristically associated with a secretory function, which suggested that the material in which the spermatozoa were immersed in the vesicle lumen was produced elsewhere along the ducts and/or during sexual maturation of the males. Spermatozoa were occasionally seen inside the inclusions, which suggested a possible spermiophagic activity for this epithelium.

Morphology and ultrastructure of the spermatozoa of Scaptotrigona xanthotricha moure (Hymenoptera, Apidae, Meliponini)

The spermatozoa of Scaptotrigona xanthotricha, a stingless bee under extinction in some Brazilian states, are described. Seminal vesicles of adult males were dissected and processed for light and transmission electron microscopy. The spermatozoa were long (about 90 µm) and slender. The head consisted of an acrosome formed by an acrosomal vesicle covering the perforatorium and the nucleus. The latter was homogeneous, compact and about 11 µm long. The flagellum consisted of an axoneme, with the typical 9+9+2 microtubule arrangement that began just below the nuclear base. The two mitochondrial derivatives were asymmetric in length and diameter, and had two accessory bodies. The nucleus was attached to the flagellum by a centriolar adjunct. These results indicate that the spermatozoa of S. xanthotricha are similar to those of other Meliponini but differ markedly from other insect groups. The ultrastructure of hymenopteran spermatozoa may be a useful character for phylogenetic studies.