The insect spermatheca: an overview.

The ultrastructure of the spermathecal epithelium of the African Migratory Locust Locusta migratoria migratorioides R. & F. (Orthoptera: Acrididae) was investigated with the aid of transmission and scanning electron microscopic methods. The unpaired spermatheca can be subdivided into a multiple coiled tube and a terminal bulb region with vestibule, small apical and extensive pre-apical diverticulum. The wall of the spermatheca consists of a chitin intima, a layer of epithelial cells with a distinct apical microvilli border and a layer of gland cells, whereby slender projections of the epithelial cells extend between the gland cells. Through extensive folding, the basal plasma membrane of the gland and epithelial cells form a huge labyrinth, which is bounded by a basal lamina. Extending into the above mentioned projections there are bundles of parallel-arrayed microtubules, which run perpendicular to the microvilli border of the epithelial cell. They end in the base region of the microvilli and in the basal labyrinth on hemidesmosomes and serve to provide a mechanically stressable anchorage for the epithelium. The gland cells show structures typical for the production of export proteins: ribosomes, rER, dictyosomes, as well as vesicles of different size and electron-density. Every gland cell contains an extracellular cavity, arising through invagination, which is coated with a microvilli border. Over an end-apparatus and a ductule joining onto it (also with chitin intima) the lumen of the extracellular cavity is connected with the spermathecal lumen. The release of secretions and other substances from the epithelium into the spermatheca lumen is as possible as the uptake of substances from the latter into the epithelium. Regional differences in the fine structure of the cuticular intima, epithelial and gland cells point to different functions of the epithelium in these regions.

Ultrastructural and functional aspects of the spermatheca of the African Migratory Locust Locusta migratoria migratorioides (Reiche and Fairmaire) (Orthoptera: Acrididae)

The mandibular glands of Blaberus craniifer are examined by histochemical, electrophoretic, thin-layer chromatography and electron microscopical techniques. These glands are known to secrete a volatile aggregative pheromone. The gregarious behaviour increases during insect development and is maximal in imagos. Each gland is composed of a bundle of secretory cells with efferent ductules which arise in a common duct. Secretory cells contain a myeloid secretion more abundant in imagos than in larval stages. Histochemical and electrophoretic criteria show that the myeloid product is made up of a mixture of glycoproteins. A lipidic component is also present in the secretion; its ultrastructural localization remains to be elucidated. Cytological features are in agreement with the gregarious behaviour of cockroaches. Detailed structure and functional interpretation are also discussed.

Les glandes mandibulaires de Blaberus craniifer burm. (Dictyoptera, blaberidae) developpement, structure et fonctionnement

The vectorial capacity of Aedes aegypti is directly influenced by its high reproductive output. Nevertheless, females are restricted to a single mating event, sufficient to acquire enough sperm to fertilize a lifetime supply of eggs. How Ae. aegypti is able to maintain viable spermatozoa remains a mystery. Male spermatozoa are stored within either of two spermathecae that in Ae. aegypti consist of one large and two smaller organs each. In addition, each organ is divided into reservoir, duct and glandular portions. Many aspects of the morphology of the spermatheca in virgin and inseminated Ae. aegypti were investigated here using a combination of light, confocal, electron and scanning microscopes, as well as histochemistry. The abundance of mitochondria and microvilli in spermathecal gland cells is suggestive of a secretory role and results obtained from periodic acid Schiff assays of cell apexes and lumens indicate that gland cells produce and secrete neutral polysaccharides probably related to maintenance of spermatozoa. These new data contribute to our understanding of gamete maintenance in the spermathecae of Ae. aegypti and to an improved general understanding of mosquito reproductive biology.

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Morphological and morphometrical assessment of spermathecae of Aedes aegypti females

Chez les Silphes et en particulier chez Phosphuga atrata, la glande de la spermatheque presente une structure particuliere liee a la presence d'une intima cuticulaire tapissant la lumiere de la glande. Elle comporte trois types cellulaires: les cellules secretrices, les cellules de l'epithelium sous-cuticulaire et les cellules-manchons. Les cellules secretrices de grande taille contiennent une invagination de la membrane cytoplasmique formant une «vacuole» extracellulaire bordee de microvillosites. Dans cette vacuole plonge l'extremite, differenciee en ampoule poreuse, d'un canalicule de nature cuticulaire, qui vehicule la secretion jusqu'a la lumiere de la glande. Le canalicule est elabore par une cellule-manchon qui l'accompagne sur toute sa longueur sauf a son extremite intravacuolaire. Ce type de glande, qui se retrouve chez de nombreux Insectes, y assurant des fonctions diverses (secretion odorifique, secretion de defense, secretion spermale, etc.), est susceptible de nombreuses variations.

Ultrastructure de la glande de la spermathèque chez Phosphuga atrata L. (Coleoptera Silphidae)

Two spermathecae occur in Periplaneta americana; their structure is basically alike but notable differences exist. Cuticular tubules (canaliculi, efferent ducts) occur within modified epidermal cells in both, extending from the lumen of the organ outward to a recurved apical termination within a secretory cell. Peripheral muscles apply hydraulic pressure to the lumen contents via the tubules; an apical valve on each tubule allows a drop of sperm to be extruded for each egg but prevents emptying of the organ. During the time from initial mating through the end of oviposition, the spermathecae of insects are highly active organs; they store and maintain sperm, and deliver them on schedule during ovipostion. The high levels of activity in the glands made them a possible site for the multiplication and accumulation of virus particles. During the course of experiments with feeding live Coxsackie virus to P. americana, these structures were routinely removed, fixed, and examined with the elec tron microscope for possible virus invasion and multiplication. The search for virus revealed very interesting basic structure in the organs, some of which is reported here. Disagreement on basic structure of this organ still persists in the literature. Snodgrass's (1937) interpretation was that there was one spermatheca with a glandular accessory structure, but Gupta (1948) reported both branches histologically alike and both containing sperm. Ross (1956) referred to a single spermatheca with a spermathecal gland attached. Marks and Lawson (1962) reported that the spermatheca in P. americana was branched, and that one branch was capitate, while the other was coiled. Smith (1968) consistently referred to the organ as a single structure in P. americana; in a later work (Gupta and Smith, 1969) paired spermathecae "opening into the genital cavity by long, 1 Published with the approval of the Director, Wyoming Agricultural Experi ment Station, as Journal Article 435. Accepted for publication June 1, 1970. Early publication paid. 2 Supported by research grant No. RG-14304, from the National Institutes of Health, Public Health Service. Journal of the Kansas Entomological Society 43:418-434. October, 1970. This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:47:58 UTC All use subject to http://about.jstor.org/terms Vol. 43, No. 4, October, 1970 419 slender ducts" were observed. The lack of agreement on the physical organization of the spermatheca was perhaps the reason the organ re ceived rather light treatment by Guthrie and Tyndall (1968). Materials and Methods Live insects were dissected from the dorsal aspect; spermathecae were removed and placed in a small container of fixative on ice. Fixa tion was for two hours in 1% Os04 buffered with veronal acetate and salts (Sjostrand, 1967). Each spermatheca was fixed intact, since each measured only about 1 mm long and % mm or less wide. Fixation was followed by dehydration in a graded acetone series and embedding in Vestopal W. Sections were cut with glass knives in an LKB ultra microtome; they were stained with 1% uranyl acetate and lead citrate and were examined with a Philips EM 300 electron microscope. For light microscopy, the posterior half of several female abdomens were cut from live specimens of P. americana and fixed in buffered formalin; these parts were embedded in Paraplast, sectioned either longi tudinally or transversely at 7 micra, and stained with haemotoxylin and eosin. For a different type of examination, both spermathecal struc tures were dissected from live females, cleared in warm KOH solution, washed and neutralized, and stained for light microscopy. Results and Discussion Dissections and light microscopy verify the presence of two sperma thecal structures in P. americana; for convenience these will be referred to as spermatheca A and spermatheca B. Spermatheca A is the struc ture called "the spermatheca" in most earlier works; it is capitate, at tached to a relatively straight duct, and is easily exposed by dorsal dis section. Spermatheca B is long, slender, and coiled, and from the dor sal approach is hidden beneath the last abdominal ganglion. The two join basally to form a common spermathecal duct traversing the sperma thecal papilla. Electron microscopy verifies the presence of sperm in both. The general structure of each of the spermathecae includes a lumen surrounded by a cuticular lining, a layer of typically functioning epider mal cells, a median (subperipheral) layer of secretory cells, and a pe ripheral layer (Figs. 1, 5) of muscle, nerves, tracheoles, and basement membrane more or less interspersed. The muscular layer is much thicker in spermatheca A (Fig. 2) than in B or in the duct (Figs. 1, 14). Light microscopy slides and KOH clearing of both spermathecae in dicate certain cuticular structure in common. A cuticular lining is present in both, as well as in the ducts. Long, slender cuticular tubules (tubular structure revealed in electron micrographs) extend outward from the central lining (Fig. 3); these are the "canaliculi [extending] into the cells of the thick glandular epithelium" (Snodgrass, 1937). This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:47:58 UTC All use subject to http://about.jstor.org/terms 420 Journal of the Kansas Entomological Society Figs. 1-2. Fig. 1. Light microscope view of spermathecal complex in P. amer icana, X 83. A?spermatheca A; B?spermatheca B; D?duct; Lg?last abdominal ganglion. Fig. 2. Light microscope view of spermatheca A of P. americana, X 216. CI?cuticular lining; Lu?lumen; Mu?muscle layer. This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:47:58 UTC All use subject to http://about.jstor.org/terms Vol. 43, No. 4, October, 1970 421 V,,/ aft. K. ^^m^m^/^^Kr "^B^^^KBm' -?' iirn H

J. C. Thomas

Papers

Ultrastructural comparison of the spermathecae in Periplaneta americana (Blattaria: Blattidae)