Sperm Pump Research Articles

Vestigial spermatheca morphology in honeybee workers, Apis cerana and Apis mellifera, from Japan

Reduction of reproductive organs in workers is one of the most important traits for caste specialization in social insects. In this study, we investigated the morphology of the sperm storage organ, the spermatheca, in workers of the honeybees Apis cerana and Apis mellifera from Japan. All examined workers of the two species retain a small spermatheca. Ultrastructural observations indicate that the spermatheca of honeybee workers consists of conspicuous muscular layers which correspond with the sperm pump and that the epithelium surrounded by these muscular layers represents the spermatheca duct. As this epithelium shows intact cellular morphology, we conclude that the spermatheca duct and the sperm pump do not degenerate, whereas the spermatheca reservoir has completely degenerated. All workers of A. cerana and most workers of A. mellifera lack the spermatheca gland completely. A few workers of A. mellifera possess the opening of the spermatheca gland, but its structure seems to be degenerated. The spermathecal width including the muscular layers showed a weak, but significant positive correlation with ovariole numbers in A. cerana, but not in A. mellifera. The degree of spermatheca gland degeneration seems to be unrelated to ovariole number. The morphological features of degeneration in honeybee workers are different from those of the vestigial spermatheca in ant workers, indicating that morphological worker virginity has evolved in a different way.

Multinucleated smooth muscles and mononucleated as well as multinucleated striated muscles develop during establishment of the male reproductive organs of Drosophila melanogaster

The adult musculature in D. melanogaster forms during metamorphosis. Much is known about the flight and leg musculature, but not about the muscles surrounding the male reproductive tract. The inner genitalia of males consist of the testes, which emerge from the gonads; the remaining genital organs, i.e., paragonia (or accessory glands), ejaculatory duct, sperm pump, and seminal vesicles, develop out of the genital imaginal disc. We analyzed the myoblasts forming the muscle layers of these organs. In myoblasts derived from the genital imaginal disc, the regulatory region of the transcription factor DMef2 is active. DMef2 is also needed for specification and differentiation of embryonic and adult myoblasts. We could discriminate three different muscle types: (i) multinucleated muscles that resemble vertebrate smooth muscles surround the testes, (ii) multinucleated muscles that resemble striated muscles comprises seminal vesicles and the sperm pump, and (iii) mononucleated striated musculature encloses the paragonia and ejaculatory duct. Members of the immunoglobulin superfamily involved in embryonic myogenesis, Dumbfounded (Duf) and Sticks and Stones (Sns), were also expressed in the genital imaginal disc, in the muscle sheath of the testes during muscle differentiation and in the secretory secondary cells, which are part of the binucleated epithelia enclosing the paragonia.

How is a giant sperm ejaculated? Anatomy and function of the sperm pump, or “Zenker organ,” in Pseudocandona marchica (Crustacea, Ostracoda, Candonidae)

'Giant sperm', in terms of exceptionally long spermatozoa, occur in a variety of taxa in the animal kingdom, predominantly in arthropod groups, but also in flatworms, mollusks, and others. In some freshwater ostracods (Cypridoidea), filamentous sperm cells reach up to ten times the animal's body length; nonetheless, during a single copulation several dozen sperm cells can be transferred to the female's seminal receptacle. This highly effective ejaculation has traditionally been credited to a chitinous-muscular structure within the seminal duct, which has been interpreted as a sperm pump. We investigated this organ, also known as the Zenker organ, of a cypridoid ostracod, Pseudocandona marchica, utilizing light and electron microscope techniques and produced a three-dimensional reconstruction based on serial semi-thin histological sections. This paper shows that numerous muscle fibers surround the central tube of the Zenker organ, running in parallel with the central tube and that a thin cellular layer underlies the muscular layer. A cellular inner tube exists inside the central tube. A chitinous-cellular structure at the entrance of the organ has been recognized as an ejaculatory valve. In male specimens during copulation, we confirmed a small hole derived from the passage of a single spermatozoon through the valve. The new data allowed for proposing a detailed course of operation of the Zenker organ during giant sperm ejaculation.

Four new species of Paraclius Loew (Diptera: Dolichopodidae) from the Brazilian Atlantic Forest, and notes on the systematic position of Cheiromyia Dyte

Four new species of Paraclius Loew from the Brazilian Atlantic Forest are described and illustrated: P. amphiatheratus, sp. nov., P. parenti, sp. nov., P. sagittatus, sp. nov., and P. dicrophallus, sp. nov. The condition of their enlarged sperm pump, also seen in the Neotropical genus Cheiromyia Dyte, is briefly discussed. Comments on the phylogenetic position of Cheiromyia are presented in light of new data from female terminalia of that genus.

The evolution of Strepsiptera (Hexapoda)

An evolutionary scenario for the enigmatic group Strepsiptera is provided, based on the results of a comprehensive cladistic analysis of characters of all life stages. A recently described fossil – † Protoxenos janzeni – the most archaic strepsipteran, sheds new light on the early evolution of the group and reduces the “morphological gap” between Strepsiptera and other insects. It weakens both current hypotheses – Coleoptera+Strepsiptera and Diptera+Strepsiptera (=“Halteria”). The splitting into † Protoxenos (Protoxenidae) and the remaining Strepsiptera was linked with a distinct size reduction and many morphological changes. Unlike males of extant strepsipteran species, † Protoxenos was still able to process food. Mengeidae († Mengea), with two small species, is the sister group of extant Strepsiptera. A unique characteristic of extant males (Strepsiptera s. str.) is the mouthfield sclerite. It is part of an air uptake apparatus which belongs to an extremely modified air-filled “balloon gut”. Besides this, male strepsipterans possess specialised antennae and compound eyes, a strongly developed flight apparatus, large testes, and a sperm pump, whereas other organ systems are strongly reduced (e.g., fat body, malpighian tubules). Males are designed to find females within a few hours and to copulate. A dramatic change is linked with the split into Mengenillidae and Stylopidia. The change to pterygote hosts and the permanent endoparasitism of the females are evolutionary novelties acquired by the latter clade, and linked with far-reaching morphological transformations, e.g. the presence of unique brood organs. Hairy tarsal adhesive devices are present in males and guarantee efficient attachment to the host during copulation. A well-founded clade within Stylopidia is Stylopiformia, which are characterised by a unique fissure-shaped birth opening. The evolutionary development towards the most specialised and successful forms (parasites of aculeate Hymenoptera [e.g., Xenidae+Stylopidae], ca. 46% of the species) is a stepwise process. The presented evolutionary scenario comprises a complex network of functionally correlated morphological changes in primary larvae, secondary larvae, females and males.

Apiformyia, a new genus of Australian bee flies (Diptera: Bombyliidae, Bombyliinae) with affinities to the New World Heterostylum Macquart

Apiformyia gen. nov. (Diptera: Bombyliidae) is described based on a large series of specimens from the Northern Territory of Australia. The specimens represent a single new species A. australis sp. nov. The genus belongs to the Bombyliinae, and has remarkable anatomical affinities to the New World genus Heterostylum Macquart. In particular, the head of Apiformyia has a sinuous posterior eye margin, but lacks a line bisecting the facets as found in most Anthracinae that also share such an eye margin. A sinuous posterior eye margin is uncommon in the subfamily Bombyliinae, being only found in Heterostylum and four other genera found in the New World, Afrotropical and Palaearctic regions. Additionally, Apiformyia shares with Heterostylum alone an unusual wing venation, with cell R 5 closed, and the apex of cell dm-cu meeting the fork of M 1 and M 2 , there being no stem of M 1+2 . The male genitalia of Apiformyia are generalized bombyliine in form, and do not share the particular unique features of Heterostylum such as the large recurved epiphallus and the gonostylus with apical beak-like process. The female genitalia of Apiformyia lack the sand chamber, acanthophorite spines and presents spermathecae with elongated bulbs, spermathecal ducts more than twice as long as sperm pump and sclerotized collars well developed, also differentiating the genus from Heterostylum.

The male genital tract and aedeagal components of the Diptera with a discussion of their phylogenetic significance

The male genital tract of Diptera is surveyed, based on whole dissections, with emphasis on nematocerous infraorders and especially the Culicomorpha. The genital tracts of all available nematocerous families are described and illustrated, including, for the first time, those of the families Thaumaleidae, Dixidae, Hesperinidae, and Pachyneuridae, and, as an outgroup, the mecopteran family Nannochoristidae (Mecoptera). On the basis of outgroup comparison, the Diptera + Mecoptera + Siphonaptera share the synapomorphies of accessory gland continuous with the vas deferens and U-shaped vasa deferentia. Further synapomorphies of the male genital tract provide evidence of the monophyly of the Mecoptera + Siphonaptera, Boreidae + Siphonaptera, and the Blephariceridae + Psychodidae + Trichoceridae + Anisopodidae + Brachycera. The Bibionomorpha, Culicomorpha, and Ptychopteromorpha share the synapomorphy of paired, two- to three-chambered accessory gland complexes, with secondary losses in Corethrellidae + Culicidae. It is concluded that there is no convincing evidence for the monophyly of the Chironomoidea. A sperm pump with an ejaculatory apodeme and the absence of a spermatophore are considered to be part of the ground plan of Diptera, but, because of uncertainty as to the identity of the basal lineage within Diptera and the homology of the sperm pump outside of Diptera, the polarity of these features cannot be presently interpreted. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 711–742.

Comparative morphology of spermathecae in solitary and primitively eusocial bees (Hymenoptera; Apoidea)

Spermathecae of solitary and primitively eusocial bees from five major families were compared according to their chamber size, epithelial cell height (wall thickness), number and shape of glands, number of sperm pumps, and diameter of the duct, using whole mounts and serial sections. A thick spermathecal wall with a small chamber in our exemplar colletid, megachilid, and andrenid bees, a large chamber with a thick wall in social Apidae, and a thin wall with a large chamber in social halictids indicate that a big chamber may be associated with increased colony size. A thin epithelium in the receptacle of halictid bees suggests relegation of spermathecal secretion to the spermathecal gland. A relatively thick spermathecal wall in the Apinae indicates the potential importance of both the epithelial cell layer of the receptacle and the enlarged spermathecal gland in maintaining large numbers of stored sperm. There was one sperm pump in all taxa surveyed except the representative Halictidae, in which this structure was paired. Elongated spermathecal glands may typify the spermathecae of eusocial bees.

Homology and phylogenetic implications of male genitalia in Diptera - Eremoneura

AbstractHomologies of male genitalic structures in the Eremoneura (Empidoidea + Cyclorrhapha) are examined and implications for the phylogenetic relationships of the included families are discussed in light of other characters. A revised epandrial hypothesis for the evolution of male genitalia within the Eremoneura is presented, based on comparison of male genitalic features throughout the Brachycera, and a periandrial hypothesis is rejected. Ground plan modifications of the genitalia of Eremoneura include complete sclerotization of the subepandrial membrane along its length to form a subepandrial sclerite, formation of bacilliform sclerites, loss of the lateral ejaculatory processes of the sperm pump, development of a deeply emarginate epandrium, and fusion of the hypandrium with the gonocoxites. Ground plan apomorphies of the Cyclorrhapha, including Opetiidae, consist of a sperm pump separated from the base of the phallus, circumversion of the genitalia, loss of the gonocoxal apodemes, and development of surstyli. The ground plan of the Empidoidea is characterized by the apomorphic loss of gonostyli, and the development of a sperm pump with a lever-like ejaculatory apodeme. Surstyli have developed independently in several lineages of Empidoidea, parallel to their development in Cyclorrhapha, as have losses of the gonocoxal apodemes. The above characters support the monophyly of the Eremoneura and also indicate that the Empidoidea and Cyclorrhapha are sister groups, as opposed to alternative hypotheses that suggest the Empidoidea is paraphyletic with respect to the Cyclorrhapha. The monophyly of Cyclorrhapha, exclusive of Opetiidae, is supported by the presence of a phallapodeme. The Lonchopteridae and Phoroidea are united partially on the basis of a similar reduction of pregenital sclerites in the male. The Phoroidea is characterized by the apomorphic loss of gonostyli and abdominal spiracle 7 in the male. The Syrphoidea and Schizophora are hypothesized to share a synapomorphic lever-like phallapodeme. The Syrphoidea is characterized by a right-side deflexion of the hypopygium, whereas the Schizophora possess gonostyli that are adducted against the hypandrium, and circumversion that is completed entirely within the puparium.

Homology and phylogenetic implications of male genitalia in Diptera - Lower Brachycera

AbstractHomology of male genitalic structures in the lower Brachycera is examined and implications for the phylogenetic relationships of the included families are discussed in light of other characters. The following character states belong to the ground plan of the Brachycera: the aedeagus is enclosed in a parameral sheath; the sperm pump possesses paired articulated lateral sclerites, and a large ejaculatory apodeme with a terminal endoaedeagal process; the epandrium and hypandrium are separate; the hypandrium is separate from the gonocoxites; and the gonostyli articulate and move in the horizontal plane. The placement of Heterostomus in Xylophagomorpha is supported, based on modifications of the sperm pump. The presence ofaedeagal tines suggests that Bolbomyia, which is currently placed in the Rhagionidae, may be more closely related to Athericidae + Tabanidae. The expanded first segment of the female cercus supports the monophyly of the Tabanomorpha, including Vermileonidae. The transfer of the Pantophthalmidae to the Stratiomyomorpha is confirmed on the basis of modifications of the sperm pump. The Stratiomyomorpha is hypothesized to be the sister group of the Muscomorpha (sensu Woodley 1989) based on the apomorphic development of a composite structure termed the phallus. The monophyly of the Muscomorpha is supported by gonostyli that articulate and move obliquely or dorsoventrally. The presence of acanthophorites in females is considered apomorphic for the Heterodactyla (Bombyliidae + Asiloidea + Eremoneura). Bombyliidae (exclusive of Mythicomyiinae and Heterotropus) is defined on the basis of reduced gonocoxal apodemes. Gonostyli retracted to a subapical position and a hinged larval metacephalic rod are considered apomorphic for the Asiloidea (exclusive of Bombyliidae) + Eremoneura. Hilarimorpha and Apystomyia are removed from the Bombyliidae based on the subapical placement of the gonostyli, and together with Apsilocephala are placed as incertae sedis in Therevidae. Apiocera is considered the sister group to the remaining apiocerids + Mydidae on the basis of absence of gonostyli and lateral ejaculatory processes in the latter lineage.

Reproductive system and terminalia of the old world screw-worm fly, Chrysomya bezziana villeneuve (Diptera : Calliphoridae)

The reproductive systems and terminalia of Chrysomya bezziana are described. The internal male reproductive system consists of paired testes, vasa deferentia, and accessory glands with a single seminal duct and sperm pump. The external male genitalia are composed basically of the aedeagus and hypandrium with their associated apodemes and a collar complex comprising a median epiphallus and paired pregonites and post-gonites. The internal female reproductive system consists of paired ovaries composed of polytrophic ovarioles, a common oviduct, 3 spermathecae, and a pair of tubular aceessory glands. After oviposition, follicular relics in the ovaries can be demonstrated which indicate previous gonadotrophic cycles. The external female genitalia are composed of sclerites from abdominal segments VI–VIII modified to form an ovipositor. The relationship of the terminalia during copulation is described.

The Cochleate Vesicle, a Highly Specialized Device for Sperm Transfer in Male Sciomyzid Flies1

The sperm pump in 23 species of Ethiopian, Oriental, con Australasian species of Sepedon is a non-musculated, sclerotized, cochleate structure, probably activated hydrostatically. It is termed the “cochleate vesicle,” and is considered an apomorphic feature in the phylogeny of the family, indicating interspecific relationship.

Fine structure of the spermatheca of Apis mellifera

The ultrastructure of the receptacle and duct of the spermatheca of non-fertilized Apis mellifera, of bees a few days after fertilization and of 2- to 3-year-old bees has been investigated. The epithelium of the receptacle does not seem to be involved in the production of secretion. Autolysomes and large amounts of filamentous material of a polysaccharide nature accumulate within the cytoplasm of old bees. The cells of the sperm duct have numerous microtubules which are believed to function as a cytoskeleton since the cells in question are periodically subject to notable compression owing to the muscular contractions of the sperm pump.

On some Neotropical Euaesthetinae (Coleoptera, Staphylinidae)

Summary Remarks on some genera and species of Neotropical Euaesthetinae (Col., Staphyli‐nidae), insects of the cryptofauna, are given. All Neotropical species of Edaphus Motschulsky are keyed, 8 species described as new: E.columbianus n.sp. (Colombia), E.mexicanus n.sp. (Mexico), E.humeralis n.sp., E.crassus n.sp., E.angulipennis n.sp., E.depressus n.sp., E.bryanti n.sp. (Brazil), and E.costaricensis n.sp. (Costa Rica). The generic characters of Tamotus Schaufuss are redescribed (including a new generic synonymy: Paredaphus Bernhauer 1915 nov.syn.), species are keyed, 2 new species are described: T.crassus n.sp. (Costa Rica, Panama) and E.brasilianus n.sp. (Brazil). Male genitalia of Tamotus consist of three pieces: the so‐called “double‐trumpet” (possibly first record of a chitinized sperm pump (?) in beetles), a large vesicula seminalis, and the edeagus. Remarks on the Neotropical Stenaesthe‐tus‐species are given including a key to species and the description of St.pammensis n.sp. (Panama). The genus Exoctavius Bierig is briefly revised: it belongs clearly to the tribe Euaesthetini and is close to Notoesthetus Saiz.

Cytological Investigations On the Male Reproductive System and the Sperm Track in the Spider Mite Tetranychus Urticae Koch (Tetranychidae, Acarina)

The post-embryonic development of the male internal genitalia, the development and production of the male germ cells, and the sperm track in the female of the two-spotted spider mite Tetranychus urticae Koch has been described. The male reproductive system consists of a testis, two vesiculae seminalis, a sperm pump, a ductus ejaculatorius and an aedeagus. The testis is a single structure in the larva, but during the nymphal stages it is generally divided into a right and a left half. The vesiculae seminalis develop from groups of cells which lie, in the larva, against the lateral sides of an epidermal invagination underneath the testis. In adults the vesiculae are provided with vesicular compartments which originate from the sheath cells. The sperm pump differentiates from the distal part of the invagination and some cells surrounding the latter. The remainder of the invagination forms the ductus ejaculatorius and aedeagus. The germ cells multiply by asynchronous spermatogonial mitoses. They are haploid with three chromosomes. Spermatocytes were not observed, which means a complete reduction of the meiosis. Spermatid formation begins at the nymphochrysalis stage and spermatozoa are found already at the deutochrysalis stage. During spermiogenesis the chromosomes lie in a line suggesting a non-random distribution in the sperm nucleus. The ripe spermatozoon is a spherical nucleus surrounded by two layers of plasm. A nuclear membrane and mitochondria were not observed. Germ cell production is continuous during the lifetime of the male, whether the males copulate or not. The numbers of the various germ cells vary dependent on the stage of life. The numbers of spermatozoa in the vesiculae seminalis and the sperm pump vary considerably, even if copulation does not take place. The numbers do not decrease during the first eight days of adulthood. The males produce an excess of spermatozoa. Ejaculations without copulation may take place. During copulation the spermatozoa are transferred behind each other with the aid of the sperm pump and may then become long-drawn because of a narrow ductus ejaculatorius or a narrow penial canal. One normal insemination supplies the female with a sufficient number of spermatozoa. The entrance to the receptaculum seminis is a short narrow tube which runs from an opening in the epidermis behind the genital opening. The receptaculum is situated posterior to the exit ducts of the ovarium and consists of about forty cells surrounding a lumen. Immediately after copulation spermatozoa are in the lumen and the basal parts of the cells. They may thus be transformed, though recovery takes place, and may adhere together forming packets. They migrate through the cells towards the haemolymph, which may take place within one day. Under influence of the growth of the oocytes and the movements of the mature eggs single spermatozoa are transported in the haemolymph towards the oocytes.

Differentiation of pulsating regions in genital imaginal discs after culture in vivo (Drosophila melanogaster).

AbstractAfter male genital discs of Drosophila melanogaster had been cultured for 8 to 19 days in the abdomens of adult female flies a number of them contained rhythmically pulsating regions. The percentage of discs which pulsated was dependent on the age of the donor larvae, the length of culture time, the presence or absence of ring glands and on the age of the host. The best conditions for the differentiation of pulsating discs were an old disc in a young host to which a ring gland from a mature larva was added.In normal development the genital disc after metamorphosis gives rise to the genital apparatus with morphologically differentiated ejaculatory duct, sperm pump and paragonia (soft parts) which contract rhythmically. In the cultured discs, however, the contractions are not accompanied by morphogenesis.The prospective fate of the pulsating region of a disc is mostly contracting soft parts of the genital apparatus, whereas the non‐contracting area forms mostly chitinous parts (anal plates, claspers, lateral plates). Other discs, e.g. leg discs and wing discs, which in normal development do not form involuntary muscles also do not contract after culture in vivo.It is concluded that the formation of pulsating regions represents a phase in the normal differention of genital discs. Some of the conditions which lead to pulsation are established early in the third instar within the cells which form the pulsating regions. Their full differentiation is influenced by hormones secreted by the ring gland.

Notes on the Phlebotomus of Panama (Diptera, Psychodidae) Vi. Phlebotomus Shannoni Dyar and Related Species1

The sandflies discussed in this paper form an ill defined group mostly lacking any outstanding peculiarities. Their grouping together is for convenience and does not imply any phylogenetic significance. The males are characterized by having four major spines but no accessory setae on the style; no basal, median or apical tufts of setae on the coxite; the parameres simple, without forks, branches or modified setae; the lateral lobes relatively long and without modified spines; the aedeagus and genital filaments of conventional form, the latter from two to four times as long as the pump and with simple tips. The flared anterior end of the plunger of the sperm pump is rather small.