Fine structure of the spermatophore and spermatozoa in inseminated females ofPergamasus mites (Acari: Gamasida: Pergamasidae)

Alberti, Gerd; Gegner, Andreas; Witaliński, Wojciech

doi:10.1002/1097-4687(200007)245:1<1::aid-jmor1>3.0.co;2-a

Cited by 15 publications

(8 citation statements)

References 27 publications

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“…It is noteworthy, that like in Parasitina, the female tissues are not simply destroyed by the sperm migration but remain intact. Thus some kind of “cooperation” between male and female cells has to be assumed (Alberti et al, ). Remarkably, the plate has a regular substructure which is reminiscent of the fine structure of an acrosomal filament (perforatorium) as it is evident in some chelicerates.…”

Section: Discussionmentioning

confidence: 99%

“…Capacitation of sperm cells is known to occur with strong structural alterations in anactinotrichid mites possessing the vacuolated type of sperm (e.g., Breucker and Horstmann, ; Oliver, ). But also the ribbon type may undergo more or less massive reconstructions (e.g., in Parasitina or Varroa destructor ; Alberti and Hänel, ; Alberti et al, ). Putative capacitated sperm cells of the modified ribbon type have also been found in Phytoseiulus persimilis (Di Palma and Alberti, ).…”

Section: Discussionmentioning

confidence: 99%

“…They were found close to the oocytes and possess a pseudopodium‐like process. Fertilization of oocytes thus occurs in the ovary (Alberti and Hänel, ; Alberti et al, ; Toyoshima et al, ). In H. cometis, the sperm cells in the inseminated female are (fortunately) still rather similar to those found in the male and thus recognizable with certainty.…”

Section: Discussionmentioning

confidence: 99%

“…During this passage, the secretion of the gland could be added to the sperm mass, thus forming a spermatophore. From Parasitina, it is known that a considerable amount of secretion is transferred into the vagina of the female (Alberti et al, ). This seems unlikely in H. cometis, since there is no space in the sperm access system of the female which could host larger amounts of secretion.…”

Section: Discussionmentioning

confidence: 99%

“…In Parasitina, after a complicated spermatogenesis, sperm cells are produced which have longitudinal ribbons composed of regularly arranged parallel rows of indentations (chambers) (Witalinski, , ; Alberti, ; Alberti and Coons, ). Spermatophores are transferred to the female genital opening and spermatozoa have been observed in the hemocoel of the inseminated female (Alberti, ; Alberti et al, ). Finally, males belonging to Dermanyssina have modified chelicerae bearing a process on the movable digit, called the spermatodactyl, which forms a tube through which spermatozoa are injected into the sperm access system of the female (Dosse, ; Krantz and Wernz, ; Di Palma and Alberti, , Di Palma et al, , , ).…”

Section: Introductionmentioning

confidence: 99%

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Ultrastructure of the male genital tract, spermatogenesis and spermatozoa of hattena cometis domrow (Acari: Gamasida: Ameroseiidae)

Alberti

Seeman

Palma

2013

Journal of Morphology

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The ameroseiid mite Hattena cometis has a male genital system that consists of an unpaired, u-shaped testis and paired deferent ducts leading into an unpaired accessory genital gland and ejaculatory duct. The genital opening is located anteriorly immediately in front of the sternal shield. Spermatogenesis is simple, probably due to the haploid nature of the male. Eight stages of spermatogenesis could be roughly distinguished. Mature spermatozoa as found in the deferent duct lumen are peculiar in having a bisected nucleus and numerous peripheral flat chambers, which were formed from indentations of the plasmalemma. In inseminated females, spermatozoa were observed in the syncytial tissue of the sperm access system and in the somatic cells of the ovary. These spermatozoa have achieved a new structure, i.e., an electron-dense plate dividing the cell into two unequal halves. The dense plate has an intricate substructure. Its function is unknown. These sperm cells are considered to represent capacitated spermatozoa. The peripheral chambers are reduced in number inside the female. Similar sperm cells, containing a dense plate, were seen in vacuoles within the epithelium of the deferent duct of one male. These cells are evidently under destruction, but before being completely dissolved had undergone a development leading beyond that of the mature sperm cells found in the deferent duct. Apparently, entering the cell of the deferent duct epithelium or the syncytium tissue triggers the production of the dense plate (or the capacitation process). Our observations are compared with results obtained from other anactinotrichid Acari, mainly Gamasida, and confirm and complete the interpretation of the correlated evolution of components of gamasid reproductive systems.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultrastructure of the male genital tract, spermatogenesis and spermatozoa of hattena cometis domrow (Acari: Gamasida: Ameroseiidae)

Alberti

Seeman

Palma

2013

Journal of Morphology

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Double spermatogenesis in Chelicerata

Alberti

2005

J. Morphol.

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Sperm dimorphism is a rare phenomenon in Chelicerata. Until now, it was known only from three species of the opilionid genus Siro (Sironidae, Cyphophthalmi). Fertilizing (eusperm) and nonfertilizing spermatozoa (parasperm) develop in the same cyst and are thus sister cells. The fine structure of the spermatozoa of two species has been examined and is compared here. In contrast to Siro rubens, S. duricorius spermatozoa lack an acrosomal complex. Both sperm types produce a transitional process, a more or less modified flagellum, which is later retracted. Hence, the spermatozoa are aflagellate. Eusperm and parasperm of all three species form highly ordered sperm balls that are stored in the deferent duct. Reviewing and adding new results about the sperm dimorphism in this arachnid taxon provides the basis for some considerations of another enigmatic morphological character found in Uropygi and Amblypygi, i.e., the tubular accessory genital glands that show holocrine extrusion. These glands are suggested to represent modified, infertile derivatives of the testis anlage. Their secretion is produced in a way reminiscent of a strongly degenerated spermatogenesis. Consequently, these products may be regarded as strongly degenerated germ cells representing a line of germ cell development, which has been separated very early in spermatogenesis from the usual line leading to fertilizing sperm cells. This further, although less evident, case of probable dichotomous germ cell development is discussed with respect to the controversial phylogenetic-systematic relationships between Uropygi (Thelyphonida and Schizomida), Amblypygi, and Araneae.

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Female genital system of the folding-trapdoor spiderAntrodiaetus unicolor (Hentz, 1842) (Antrodiaetidae, Araneae): Ultrastructural study of form and function with notes on reproductive biology of spiders

et al. 2005

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The genitalia of the female folding-trapdoor spider Antrodiaetus unicolor are characterized by two pairs of spermathecae that are arranged in a single row and connected to the roof of the bursa copulatrix. Each single spermatheca is divided into three main parts: stalk, bowl, and bulb, which are surrounded by the spermathecal gland. The epithelium of the spermathecal gland is underlain by a muscle meshwork and consists of different types of cells partly belonging to glandular cell units (Class 3 gland cells) that extend into pores in the cuticle of the stalk and bowl. Interestingly, the bulb lacks glandular pores and is characterized by a weakly sclerotized cuticle. This peculiarly structured bulb probably plays an important role in the discharge of the sperm mass. It is suggested that by contraction of the muscle layer the sperm mass may be squeezed out, when the bulb invaginates and expands into the spermathecal lumen, pushing the sperm to the uterus lumen. Each glandular unit consists of usually one or two central secretory cells that are for the most part surrounded by a connecting cell that again is surrounded by a canal cell. The canal cell, finally, is separated from the other epithelial cells (intercalary cells) located between the glandular units by several thin sheath cells that form the outer enveloping layer of the unit. The secretions are released through a cuticular duct that originates proximally between the apical part of the connecting cell and the apical microvilli of the secretory cells and runs into a pore of the spermathecal cuticle. The glandular products of the Class 3 gland cells likely contribute to the conditions allowing long-term storage of the spermatozoa in this species. Details regarding the ovary, the uterus internus, and the uterus externus are reported. Most of the secretion that composes the chorion of the egg is produced in the ovary. Glandular cell units observed in the uterus externus differ structurally from those in the spermathecae and likely play a different role. Finally, we briefly discuss our results on the female genitalia of A. unicolor in the light of knowledge about the reproductive biology of spiders.

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Fine structure of the spermatophore and spermatozoa in inseminated females ofPergamasus mites (Acari: Gamasida: Pergamasidae)

Cited by 15 publications

References 27 publications

Ultrastructure of the male genital tract, spermatogenesis and spermatozoa of hattena cometis domrow (Acari: Gamasida: Ameroseiidae)

Ultrastructure of the male genital tract, spermatogenesis and spermatozoa of hattena cometis domrow (Acari: Gamasida: Ameroseiidae)

Double spermatogenesis in Chelicerata

Female genital system of the folding-trapdoor spiderAntrodiaetus unicolor (Hentz, 1842) (Antrodiaetidae, Araneae): Ultrastructural study of form and function with notes on reproductive biology of spiders

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