The glandular units of the spermathecae of machilids (microcoryphia) : Ultrastructure and modifications during moulting

The spermathecae of 4 species of Microcoryphia (Lepismachilis targionii, Trigoniophthalmus alternatus, Machilis sp. and Machilinus rupestris) present characteristics related to the primitive phylogenetic position of these apterygote insects. They are paired organs situated in the 8th abdominal segment on each side of the rudimentary genital chamber. Each spermatheca includes 2 different tissues: (a) a simple epithelium surrounding 2 spermathecal capsules and communicating with the genital chamber by short ducts; (b) a complex glandular tissue composed of numerous functional units, each made up of several cell types — a large glandular cell with a subapical reservoir, 2 basal cells, a ductule cell and enveloping cells. One of the basal cells, called the ciliary cell, presents a dendrite-like process containing 2 apical centrioles in alignment. Several ductules of neighbouring units join together before opening in the genital chamber, independently of the ducts of the spermathecal capsules.The spermathecae undergo marked changes during moulting periods. Apolysis is followed by a partial dedifferentiation of the glandular cells, then the formation of new ductule cavities and the growth of a pseudocilium at the apex of the dendrite-like process of each ciliary cell. Afterwards, cuticular material is laid down around the pseudocilia, forming the intima of the new ductules, which results from the secretions of at least the ciliary and ductule cells. The pseudocilia degenerate before ecdysis. A comparison is made with the organogenesis of analogous organs described in different insect species.     

Ultrastructure of the Accessory Glands in Female Genitalia of Pholcus phalangioides(Fuesslin, 1775) (Pholcidae; Araneae)

Pholcus phalangioidesdoes not possess receptacular seminis. The uterus externus (genital cavity) itself functions as a sperm storage structure. Two accessory glands are situated in the dorsal part of the uterus externus; they discharge their secretory product into the genital cavity. The secretion is considered to serve primarily as a matrix for sperm storage, i.e. to keep the spermatozoa in a fixed position. The accessory glands consist of numerous glandular units, each being composed of four cells: two secretory cells are always joined and surrounded twice by an inner and an outer envelope cell. Both envelope cells take part in forming a cuticular ductule that leads from the secretory cells to the pore plates of the uterus externus. The inner envelope cell produces the proximal part of the canal close to the microvilli of the secretory cells, whereas the outer envelope cell produces the distal part of the canal leading to the pore plate. Close to the pore the latter exhibits prominent microvilli that might indicate additional secretory activity.     

Ultrastructural modifications of the glandular epithelium of the receptaculum seminis in Thermobia domestica (Insecta: Thysanura) during the moulting period

Summary The wall of the receptaculum seminis of Thermobia domestica is composed of numerous glandular units, each with four enveloping cells (denoted 1 to 4) separated by ordinary epithelial cells and associated with a cuticular apparatus. During the moulting periods, which continue to occur in the adult stage, these cells undergo a series of transformations. Just before apolysis there is a dedifferentiation of numerous cytoplasmic organelles, but no mitosis has been observed. When the intima lifts off, the apical system of each glandular unit, i.e. the distal parts of the C2 and C3 cells surrounding the end apparatus, is also eliminated. Then at the apex of each glandular unit, a new ductule is formed in the cavity of which a long ciliary process grows up from cell C1. Finally comes the phase of cuticle formation, i.e., epicuticle for the ductules, epi-and endocuticle for the intima lining the central cavity of the receptaculum. Various cell types participate in secretion of cuticle, the ciliary cells (C1) being responsible for the formation of the porous end apparatus. At ecdysis almost all of the new intima has been secreted and the apical systems are once more differentiated. These transformations are compared with those recently described in other exocrine glands of arthropods, e.g., tegumentary glands and accessory glands of the genital ducts.     

Rosette glands in the gills of the grass shrimp Palaemonetes pugio. II. Premolt ductule reformation: Replacement of ciliary processes by cytoplasmic processes in relation to gland maturation

The events associated with premolt reformation of the cuticularized ductule in the underdeveloped (immature) branchial rosette glands, which are common in the gills of small (14–18 mm, total length) grass shrimp, are described and contrasted with the events of ductule reformation in the fully developed (mature) resette glands most common in larger shrimp. In immature rosette glands, two ciliary processes emerge from each of the component secretory cells and ascend into the basal luminal region of the old ductule. Subsequently a new ductule is formed around the old ductule, and the ciliary processes disappear, either because of degeneration or retraction. The transitory ciliary processes appear to prevent the old ductule from collapsing during the formation of a new ductule. Such transitory ciliary processes, however, are not found in association with premolt ductule reformation in the mature rosette glands; in their place are seen a number of microvilli-like cytoplasmic processes, which emanate from the apices of the secretory cells and from the channels of the central cell. These cytoplasmic processes in mature glands, like the ciliary processes in immature glands, are transitory and appear to prevent the collapse of the old ductule. Cytoplasmic processes comparable to those in mature glands, but relatively few in number and originating only from the secretory cells, are seen together with ciliary processes in some immature glands. The relative abundance of cytoplasmic processes in the mature glands, coupled with the observation that transitory ciliary processes occur in immature glands but not in mature glands, suggests that, during glandular maturation, transitory ciliary processes are replaced by transitory cytoplasmic processes.     

Ultrastructure of an exocrine dermal gland in the gills of the grass shrimp,Palaemonetes pugio: Occurrence of transitory ciliary axonemes associated with the sloughing and reformation of the ductule

Exocrine dermal glands, comparable to the class 3 glandular units of insects, are found in the gills of the grass shrimp, Palaemonetes pugio. The dermal glands are composed of three cells: secretory cell, hillock cell and canal cell. Originating as a complex invagination of the apical cytoplasm of the granular secretory cell, a duct ascends through the hillock and canal cells to the cuticular surface. The duct is divisible into four regions: the secretory apparatus in the granular secretory cell, the locular complex, the hillock region within the hillock cell and the canal within the canal cell. A tubular ductule is contained within the latter two regions. As the ductule ascends to the cuticular surface, its constitution gradually changes from one of a fibrous material to one which possesses layers of epicuticle. During the proecdysial period, the ductule is extruded into the ecdysial space and this is followed by the secretion of a new ductule. Temporary ciliary structures, located near the secretory apparatus of the secretory cell, are associated with the extrusion and reformation of the ductule. Characterized only by a basal body and rootlets throughout most of the intermolt cycle, the ciliary organelles give rise to temporary axonemic processes which ascend through the ductule toward the ecdysial space at the onset of proecdysis. Subsequently, the old ductule is sloughed off and a new ductule is reformed around the ciliary axonemes. Following this reformation, the ciliary axonemes degenerate. The function of cytoplasmic processes, derived from the apical cytoplasm of the secretory cell, is also discussed.     

Fine structure of the pygidial glands of Bledius mandibularis (coleoptera : staphylinidae)

The pygidial glands of B. mandibularis produce a mixture of terpenes, fatty acid derivatives, and a benzoquinone. The morphology of these glands is described with particular attention to the ultrastructure of the secretory cells and their efferent ductules. Each functional secretory unit consists of two secretory cells (cortical and medullary) both of which are associated with a common extracellular cuticular ductule. The fenestrated tip of the ductule lies in a cavity bounded by the invaginated plasma membrane of the cortical cell; within the cavity surrounded by the medullary cell, the ductule is divided into a bulb region (where a spherical mass of fine cylinders surrounds the ductule itself) and an unfenestrated switchback region. Inflated cisternae of rough endoplasmic reticulum, filled with flocculent material of low electron density, are abundant in the cortical cytoplasm, and presumably represent primary secretory product en route to the cavity of this cell. The plasma membrane bounding this cavity is much infolded, and the inner surface of this membrane is studded with fine particles. In contrast, few cisternae are inflated in the medullary cell and the corresponding infolded plasma membrane is smooth. The manner in which both cells may cooperate to produce the heterogeneous secretory product is discussed.     

Tegumentary glands of the supra-anal pit of Scutigerellidae (Symphala, Myriapoda)]

Tegumentary glands of the 'supra-anal pit' in the genus Scutigerella are ductule-associated glandular cells. The invaginated cavity consists of two distinct parts, the inner bearing microvilli collector. The efferent ductule penetrates into the upper part of the cavity by means of a receiving tubule, the wall of which is perforated and composed of two layers having different electron densities. The glandular cell cytoplasm is packed with smooth endoplasmic reticulum which arises from rough endoplasmic reticulum and by blebbing of the outer membrane of the nuclear envelope, blebs immediately losing their ribosomes. Secretion granules are released into the extracellular invaginated cavity between the microvilli and form an amorphous layer that covers the cuticular invagination of the 'supra-anal pit'.     

Modifications ultrastructurales des glandes vésiculaires des Machilidae (Insecta,Thysanura) au cours des cycles de mue

Summary During the period between apolysis and ecdysis, the vesicular glands show many important transformations which affect not only the cuticular ductules, but all the cells. The cytoplasm of the glandular cells undergoes a partial autolysis, whereas other parts of the cells present a high secretory activity. Immediately after the apolysis the cellular reservoir empties and disappears almost completely; soon after, refills with secretion. The most interesting transformations concern each ciliary cell, always associated with a glandular cell. In the first phase of the moulting cycle, the dendrite of the ciliary cell grows a ciliumlike extension (= distal region of the dendrite), which penetrates into the corresponding ductule; the new intima of this ductule is laid around the cilium. At the same time, the proximal region of the dendrite forms a circular fold around the base of the cilium and begins to secrete a material which will form the end apparatus. This latter is finished during the second phase of the cycle. The third phase is characterized by the degeneration of the distal region of the dendrite and the circular fold. Thus, the end apparatus is not a secretion of the ductule-carrying cell, but of the ciliary cell. At the end of the moulting period, just before ecdysis, the vesicular gland again takes the structure characteristic of the intermoult: the reservoir of the glandular cell is very large; the cuticular apparatus is almost formed; the dendrite of the ciliary cells shows, at its apex, a short cilium (= ciliary region s. str. + short distal region) surrounded by microvilli, free in the secretion of the reservoir.     

Ultrastructural and phylogenetic assessment of wax glands in pit scales (Homoptera : Coccoidea)

TEM/SEM and computerized images of 5 wax glands for 3 type species of Coccoidea (Homoptera): Asterodiaspis variolosa (Asterolecaniidae), Cerococcus quercus (Cerococcidae) and Lecanodiaspis sardoa (Lecanodiaspididae) were studied. Their cuticular structures were compared with 142, 56, and 61 species in their respective families to determine relationships among pit scale taxa. Significant differences include: the morphology of the outer and inner ductule of the tubular duct gland, structure of the pores (8-shaped, multilocular and quinquelocular), and the absence or presence of cribriform plates and their structural variations. Three distinctive tubular duct shapes (asterform, ceroform and lecanoform) are common in pit scale species. Apomorphic characteristics of the asterform tubular ducts include an absence of the inner ductule and the progressive reduction of the outer ductule's diameter from the pore to its inner end. These characters easily separate asterolecaniids from the cerococcid-lecanodiaspidid lineage. The constricted lecanoform tubular ducts and the curved teeth on the rim at the inner end of the outer ductule in the ceroform tubular ducts are regarded as autapomorphic. The presence of 8-shaped pores is considered a plesiomorphic condition. Specific cuticular variations of the 8-shaped pores, characterizing familial taxa, include pores even with the surface in asterolecaniids, pores with raised walls in cerococcids, and bent pores in lecanodiaspidids. The dominant 8-shaped pore patterns in pit scales are those arranged in a marginal band in lecanodiaspidids, in a swirl-like pore pattern in the cerococcids, and in a marginal row in asterolecaniids. A divergent evolutionary trend is noted for the structure of the cribriform plate; they are with micro-orifices in cerococcids, but without micro-orifices in lecanodiaspidids. The former state is considered apomorphic. Cribriform plates arranged in clusters characterize the cerococcids, while plates in longitudinal rows characterize the lecanodiaspidids. These data confirm the concept that the pit scales constitute a paraphyletic group and the Asterolecaniidae, Cerococcidae and Lecanodiaspididae are monophyletic.     

Ultrastructure and ontogeny of the hair sensilla on the funicle of Calliphora erythrocephala (Insecta,Diptera)

Summary Four envelope cells are responsible for the formation of the basiconical sensilla of Calliphora. They are the thecogen, trichogen, and tormogen cells, and envelope cell 4. In early stages of development the still subepithelial sensory cilia are completely enclosed by the innermost thecogen cell. The first formation movements are initiated by a growth thrust of the hair-forming cell into the exuvial space. The sensory cilia only begin to grow into the hair anlage when the hair-forming cell has almost reached its final length. As soon as growth is completed the trichogen cell, tormogen cell, and envelope cell 4 start to excrete cuticular material. The trichogen cell forms the perforated part of the hair shaft and the stimulus-conducting system consisting of the pore tubules. The tormogen cell is responsible for the excretion of the basal non-perforated hair shaft and sheath cell 4 forms the proximal part of the socket region. The thecogen cell only begin to produce dendritic sheath material when the sensory hair is almost complete.Approximately 7–8 days after pupation the tormogen cell degenerates, having, by this time, produced about two-thirds of the sensilla cuticle. The surrounding envelope cells incorporate cell fragments of the tormogen cell. The trichogen cell continues the secretion where the tormogen cell left off. When the secretion of cuticle is finished the sheath cells begin to withdraw towards the proximal direction and to form microvilli on the apical membrane. The resulting outer receptor lymph space is bordered by envelope cell 4 and the trichogen and thecogen cells. The tormogen cell is absent in the sensilla of the imago.Abbreviations DS dendritic sheath - E4 envelope cell 4 - Ex exuvial space - G glial cell - iD inner dendritic segment - iRL inner receptor lymph space - oRL outer receptor lymph space - oD outer dendritic segment - P pore - PT pore tubules - S sensory cell - T thecogen cell - TO tormogen cell - TR trichogen cell Part 1 of a dissertation accepted by the Faculty of Bio- and Geosciences, University of Karlsruhe     

Disk formation in retinal cones of Tupaia belangeri (Scandentia)

Existing hypotheses on the mode of disk formation in the photoreceptor cells of mammals appear to be incompatible: (1) plasma membranes of adjacent evaginations form a disk which, subsequently, is internalized by a disk rim; (2) pinocytotic vesicles are pinched off from the plasma membrane and fuse into a larger vesicle, which flattens and forms a disk. We have studied the development of the cone outer segment and the disk formation in Tupaia belangeri by transmission electron microscopy. During the first two postnatal weeks, the distal part of the single cilium, which is inserted apically on the inner segment, becomes balloon-shaped. Apical to the axoneme, it contains tubular and vesicular material, which, most probably, has been detached from the axonemal microtubules. These tubules and vesicles do not contribute to disks. The balloon-shaped expansion, later retained as the ciliary backbone, establishes the contact with the pigment epithelium. Formation of disks, from the 12-day-old Tupaia onwards, occurs between adjacent evaginations at the outer segment base. The initial disk rims are “hooked” to the ciliary axonemal microtubules. The axonemal microtubules are involved in the initiation and in the alignment of the disks. Disk rim formation and, thus, internalization of disks proceeds from the base to the apex of the outer segment, that is, from the younger to the older disks. In the adult Tupaia, an uneven progression of disk rim formation on both sides of the axoneme is found among consecutive disks. The seemingly incompatible hypotheses on the mode of disk formation reflect a heterochrony of the internalization of membranes and of the disk formation among different mammals and, possibly, between cones and rods. Received: 24 July 1997 / Accepted: 10 September 1997     

The structure of the postantennal organ in Onychiurus sp. (Insecta: Collembola) and its connection to the central nervous system

Summary The postantennal organ in Onychiurus (group armatus) is a sensory organ comprising one sensory cell, several enveloping cells and cuticular structures.The perikaryon of the sensory cell is located in the central nervous system and distally gives off a dendrite in which one inner and two outer segments are distinguishable. Two ciliary structures connect the outer dendritic segments with the inner segment. The outer segments divide repeatedly, basal to the cuticular structures, into small branches which end distally beneath the cuticular wall. The wall of the cuticular structures is very thin and is pierced by numerous funnel-shaped pores. The pores are filled with electron-dense material which forms a continuous sheath underneath the cuticle. This material encases the small dendritic branches and the processes of the enveloping cells which occupy the lumen of the cuticular structures. There are three types of enveloping cells: one inner, several outer and one basal. Their processes differ in the manner in which they envelop the various regions of the dendrite.At the beginning of moulting outer dendritic branches are not found within the cuticular structures of the organ. They may be assumed to retract inwardly. However, in the later stages, when the cuticle is fully formed, the outer dendritic segments appear to divide. It is assumed that the small dendritic branches reach their targets before ecdysis. The electrondense material which clogs the intermoult cuticular pores is absent until the final stages of the moulting cycle.Supported by a grant from the Deutscher Akademischer Austauschdienst.     

Internal proprioceptive organs of the distal antennal segments in Allacma fusca (L.) (Collembola : Sminthuridae): Proprioceptors phylogenetically derived from sensillum-bound exteroceptors

The internal proprioceptive organs of the distal antennal segments of Allacma fusca (Collembola : Sminthuridae) were examined with light, scanning, and transmission electron microscopy. There are 2 such organs, each belonging to the sensory equipment of a sensory peg. These pegs are part of the sensory organs of the 3rd antennal segment (SO - AIII), and show characteristics of both hair sensilla and chordotonal organs. They have 5 sensory cells of which 4 can be regarded as chemoreceptors, because the walls of the pegs are pierced by pores. The 5th cells are the proprioceptors. Their dendritic outer segments are connected to the base of the SO - AIII peg but show no specializations. Their dendritic inner segments are distally joined to a thecogen cell containing a scolopale. Proximally, they span the hemolymph space within the antenna. The perikaryon of one of the organs is located on a muscle that deflects the 3rd antennal segment (IP - AIII). The perikaryon of the other is attached to the antennal nerve near a point where it is connected to a muscle that deflects the 4th antennal segment (IP - AIV). There is a conspicuous membrane system, associated with microtubules and a prominent ciliary rootlet within the dendritic inner segment of the IP - AIII. The cytological features of the organs are discussed with reference to 2 problems, the phylogeny of chordotonal organs and the process of mechanosensory transduction.     

Morphology and ultrastructure of the dufour's and venom gland in the ant,Myrmica rubra (L.) (Hymenoptera : Formicidae)

The morphology and fine structure of the Dufour's and venom gland, as well as their entrance into the sting, are described in the myrmicine ant, Myrmica rubra (Hymenoptera : Formicidae). The epithelial cells that constitute the Dufour's gland wall, contain a well-developed smooth endoplasmic reticulum. Older workers, compared with younger ones, show an increasing number of multilamellar inclusions. The venom gland secretory cells are arranged in 2 free filaments that carry the secretion to the reservoir. Their cytoplasm shows an intracellular collecting ductule with surrounding microvillar sheath, and an abundance of free ribosomes. However, a well-organized granular endoplasmic reticulum, which is typical in species with a more powerful sting, does not occur. Both the Dufour's and venom gland ducts are characterized by the insertion of extensive muscle fibres, which act as a precise and mutually independent control mechanism for the discharging activities of the 2 glands.     

Postembryonic development and homology of external genitalia in Galloisiana nipponensis (Caudell et king) (Notoptera : Grylloblattidae)

The postembryonic development of genital and postgenital segments of Galloisiana nipponensis (Notoptera : Grylloblattidae) have been described in detail. The coxite, stylus, epiproct and paraproct are already observed in the first nymphal instar, but the sexual characters are almost indistinguishable in the 1st to 4th nymphal instars, because the genital segments in these stages are not yet differentiated. In the 5th nymphal instar in the male, the paired primary phallic lobes start to appear at the hind margin of the 9th sternum. The rudiments of ventral valvulae in the female originate at the hind margin of the 8th sternum. In the 6th nymphal instar, the rudiments of inner valvulae begin to appear on the 9th sternum, in addition to the ventral valvula rudiments. The long dorsal valvulae are formed from the extension of nymphal coxite, while the nymphal styli are more reduced than those of younger instars.The ventral valvulae of the 8th abdominal segment are thought to be homologous with the inner valvulae of the 9th segment, judging from their site and mode of development. Further, the inner valvulae may also be homologous with the primary phallic lobes (phallomeres) of the male. The external genitalia in G. nipponensis originate from 2 structures: the dorsal valvulae (considered of appendicular origin), and the phallomeres; ventral and inner valvulae are regarded as mere integumentary outgrowths.     

Ultrastructure of a possible new type of crustacean cuticular strain receptor in Carcinus maenas (crustacea,decapoda)

A hitherto unknown sensillum type, the “intracuticular sensillum” was identified on the dactyls of the walking legs of the shore crab, Carcinus maenas. Each sensillum is innervated by two sensory cells with dendrites of “scolopidial” (type I) organization. The ciliary segment of the dendrite is 5–6 μm long and contains A-tubules with an electron-dense core and dynein arm-like protuberances; the terminal segment is characterized by densely packed microtubules. The outer dendritic segments pass through the endo- and exocuticle enclosed in a dendritic sheath and a cuticulax tube (canal), which is suspended inside a slit-shaped cavity by cuticular lamellae. The dendrites and the cavity terminate in a cupola-shaped invagination of the epicuticle. External cuticular structures are lacking. Three inner and four to six outer enveloping cells are associated with each intracuticular sensillum. The innermost enveloping cell contains a large scolopale that is connected to the ciliary rootlets inside the inner dendritic segments by desmosomes. Scolopale rods are present in enveloping cell 2. Since type I dendrites and a scolopale are regarded as modality-specific structures of mechanoreceptors, and since no supracuticular endorgan is present, the intracuticular sensilla likely are sensitive to cuticular strains. The intracuticular sensilla should be regarded as analogous to insect campaniform sensilla and arachnid slit sense organs.     

Ultrastructure des sensilles trochanteriens de Campodea sensillifera conde et mathieu (Diplura : Campodeidea)

The fine structure of the basiconica sensilla situated on the posterior part of trochanters in Campodea sensillifera (Diplura : Campodeidea) reveals that they are probably olfactory and mechano-sensitive setae. Each sensillum is composed of one sensory axis made of 3 dendrites ensheathed by 3 cells (thecogen, trichogen and tormogen); one outer segment ends by a tubular corper without connection with the cuticular layer. The setae are generally racket-shaped. The epicuticular layer of the expanded part is perforated by a lattice of numerous slits, which communicate with underlying canals. The ciliary structures and apex of the tormogen cell are eliminated just before ecdysis. The ciliary microtubules are present in the cavity of the new sensillum, but after ecdysis the microtubules persist only at the lower part of the peduncle. An ecdysial canal appears at the tip of the sensillum.     

Rhodopsin transport in the membrane of the connecting cilium of mammalian photoreceptor cells

The transport of the photopigment rhodopsin from the inner segment to the photosensitive outer segment of vertebrate photoreceptor cells has been one of the main remaining mysteries in photoreceptor cell biology. Because of the lack of any direct evidence for the pathway through the photoreceptor cilium, alternative extracellular pathways have been proposed. Our primary aim in the present study was to resolve rhodopsin trafficking from the inner to the outer segment. We demonstrate, predominantly by high-sensitive immunoelectron microscopy, that rhodopsin is also densely packed in the membrane of the photoreceptor connecting cilium. Present prominent labeling of rhodopsin in the ciliary membrane provides the first striking evidence that rhodopsin is translocated from the inner segment to the outer segment of wild type photoreceptors via the ciliary membrane. At the ciliary membrane rhodopsin co-localizes with the unconventional myosin VIIa, the product of human Usher syndrome 1B gene. Furthermore, axonemal actin was identified in the photoreceptor cilium, which is spatially co-localized with myosin VIIa and opsin. This actin cytoskeleton of the cilium may provide the structural bases for myosin VIIa-linked ciliary trafficking of membrane components, including rhodopsin.     

TEM studies on the lattice organs of cirripede cypris larvae (Crustacea, Thecostraca, Cirripedia)

 Lattice organs consist of five pairs of sensory organs situated on the dorsal carapace in cypris larvae of the Crustacea Cirripedia. The lattice organs in cypris larvae of Trypetesa lampas (Acrothoracica) and Peltogaster paguri (Rhizocephala) represent the two main types found in cirripedes, but only minor differences exist at the TEM level. Each lattice organ is innervated by two bipolar, primary receptor cells. The inner dendritic segment of each receptor cell carries two outer dendritic segments. The outer dendritic segments contain modified cilia with a short ciliary segment (9×2+0 structure). Two sheath cells envelop the dendrite except for the distal ends of the outer dendritic segments. This distal end enters a cavity in the carapace cuticle and reaches a terminal pore situated at the far end of the cavity. The cuticle above the cavity is modified. In both species the epicuticle is partly perforated by numerous small pores and the underlying exocuticle is much thinner and less electron dense than the regular exocuticle. Lattice organs very probably have a chemosensory function and are homologous with the sensory dorsal organ of other crustacean taxa. Accepted: 18 August 1998     

黄胫小车蝗受精囊的亚显微结构

利用组织学方法,观察了黄胫小车蝗Oedaleus infernalis 受精囊的显微与亚显微结构。结果表明,黄胫小车蝗受精囊为单个,由高度卷曲的受精囊管和蚕豆状的端囊构成。受精囊壁主要由表皮层、上皮层、基膜和肌肉层构成;上皮层包含上皮细胞、导管细胞和腺细胞。上皮细胞在靠表皮层的边缘有大量的微绒毛,两相邻上皮细胞的细胞膜相互嵌入,并有细微的突起延伸在导管细胞及腺细胞之间,直到基膜,达基膜处的上皮细胞膜折叠,与腺细胞膜的折叠,一起形成迷宫样的指状突起,附着在基膜上。导管细胞有一个较大的核和分泌导管,连接于腺细胞的细胞腔和受精囊腔,将腺细胞中分泌物运输到受精囊腔中。腺细胞具有典型的分泌细胞特征： 含发达内质网、高尔基复合体及不同大小的囊泡。肌肉层位于受精囊最外层,附在基膜上。在受精囊不同部位的结构有差异。在交配前和交配后,受精囊腺细胞的亚显微结构也有差异。