The spermatheca ultrastructure of the ground beetle Clinidium canaliculatum (Costa) (Carabidae, Rhysodinae).

The ground beetle Clinidium canaliculatum is a member of Rhysodinae, a taxon with still discussed systematic position. The spermatheca of this species is a small cylindrical structure connected to the common oviduct by a thin duct. The ultrastructure of the organ has revealed that the apical receptacle is provided with an epithelium lined by a thick cuticle from the deeper region of which several finger-like cuticular structures extend into the cytoplasm. On these structures adhere microtubule bundles that cross the whole cytoplasm to anchor on short densities along the basal plasma membrane. These specializations are strongly reminiscent of the hemidesmosomes, possibly playing a mechanical role enabling the cells to resist to the muscle contractions pushing the sperm towards the spermathecal duct. The cells are rich in mitochondria and glycogen granules and they are possibly involved in fluid uptake from the spermathecal lumen. The spermathecal duct has a simple epithelium lined by a soft cuticle. The sperm present in the apical receptacle and in the duct lumen maintain the structure described in the male genital apparatuses. They are generally free and embedded in a homogeneous electron-dense material. Occasionally, a sperm bundle, still with an apical cap, was visible in the spermathecal receptacle.

Ultrastructure of the female reproductive organs of the diving beetle Deronectes moestus incospectus (Leprieur, 1876) (Dytiscidae, Hydroporinae).

We describe the ultrastructure of the female reproductive organs of Deronectes moestus (Dytiscidae Hydroporinae). The long spermathecal duct has a simple epithelium lined internally by a thin cuticle and externally by a thick layer of muscle cells. The wide duct lumen contains electron-dense material, among which remnants of extracellular material are visible. This material consists of tubular structures assembled around sperm bundles previously described in the male deferent ducts. The so-called gland, disposed along the spermathecal duct, is a structure with epithelial cells lined by an irregular cuticle bearing a rich system of microvilli. Many mitochondria are visible in the apical cytoplasm of the epithelial cells, and a few spheroidal bodies are close to the basal nuclei. Since the epithelial ultrastructure of the gland suggests it is involved in fluid uptake from the lumen rather than secretory activity, the term gland, coined by other authors to describe this organ, is inappropriate. The spermatheca is a large structure with a complex epithelium showing secretory and duct-forming cells. The lumen of this organ contains sperm with the distinctive ultrastructural features of those described in the male deferent ducts, namely having a mitochondrial matrix with a small crystallized area and electron-dense dots. Because to its overall organization, the spermatheca of D. moestus can be considered a more integrated organ than those in previously studied hydroporine species.

Comparative Morphology of Wax Gland Heads in Adult Dustywings (Insecta: Neuroptera: Coniopterygidae).

In the largest comparative study of coniopterygid wax gland head morphology to date, we used scanning electron microscopy to illustrate the ultrastructure of gland heads found in 2 subfamilies (Aleuropteryginae and Coniopteryginae), 5 tribes (Aleuropterygini, Coniocompsini, Coniopterygini, Conwentziini, and Fontenelleini), 9 genera (Aleuropteryx, Coniopteryx, Coniocompsa, Conwentzia, Cryptoscenea, Heteroconis, Semidalis, Spiloconis, and Thecosemidalis), and 28 species of Palearctic and Oriental dustywings collected from a variety of sites across China. We propose a new descriptive terminology to concisely characterize the major elements of gland head ultrastructure and then identify similarities and differences among them and provide detailed descriptions of the wax gland heads found in each of the nine genera examined. Based on the range of taxa examined, we propose hypotheses about the functional morphology of some of the ultrastructural elements examined and relate them to wax ring formation in dustywings. An identification key for the examined genera based on gland head morphology is also presented.

Sperm structure of the diving beetle Deronectes moestus incospectus (Leprieur, 1876) (Hydroporinae, Dytiscidae) and considerations on extracellular material surrounding sperm bundles.

The sperm cells of the diving beetle Deronectes moestus incospectus are characterized by sperm conjugation leading to the formation of sperm bundles of 64 units each. These bundles are formed at the end of spermatocyte cell divisions occurring in the testes and can be detected in the anterior region of the deferent ducts (first type of sperm conjugation). Fusions of some sperm bundles can occur at the end of the deferent ducts. The sperm bundles show sperm-head stacks (sperm rouleaux) and are surrounded by a cup of extracellular material secreted by the epithelial cells of the deferent ducts. This material extends posteriorly around the sperm bundle to cover the nuclei and the initial region of the sperm flagella. The cup extracellular material consists of fine tubules, and is no longer visible in sperm bundles at the posterior end of the deferent ducts. The sperm cells of D. moestus incospectus have an axoneme with a 9 + 9 + 2 pattern and unusual mitochondrial derivatives having a matrix showing dense dots and a small crystallized domain. Two thin elongated accessory bodies are located between the mitochondrial derivatives and the axoneme. The extracellular material can have different morphologies in the various families of Adephaga, but all are produced by the epithelium of the deferent ducts. Thus it is reasonable to assume that it has the same function in the different groups.

The Structure of the Female Genital System of the Diving Beetle Scarodytes halensis (Fabricius, 1787) (Hydroporinae, Dytiscidae), and the Organization of the Spermatheca and the Spermathecal Gland Complex.

The fine structure of the female reproductive organs of the diving beetle Scarodytes halensis has been described, with particular attention to the complex organization of the spermatheca and the spermathecal gland. These organs are fused in a single structure whose epithelium is involved in a quite different activity. The secretory cells of the spermathecal gland have a large extracellular cistern with secretions; duct-forming cells, by their efferent duct, transport the secretions up to the apical cell region where they are discharged into the gland lumen. On the contrary, the spermatheca, filled with sperm, has a quite simple epithelium, apparently not involved in secretory activity. The ultrastructure of the spermatheca is almost identical to that described in a closely related species Stictonectes optatus. Sc. halensis has a long spermathecal duct connecting the bursa copulatrix to the spermatheca-spermathecal gland complex. This duct has a thick outer layer of muscle cells. Through muscle contractions, sperm can be pushed forwarding up to the complex of the two organs. A short fertilization duct allows sperm to reach the common oviduct where eggs will be fertilized. The different organization of the genital systems of Sc. halensis and S. optatus might be related to a different reproductive strategy of the two species.

Sperm ultrastructure in several species of Carabidae beetles (Insecta, Adephaga) and their organization in spermatozeugmata.

Sperm structure of seven species from different Carabidae tribes was studied. Carabus preslii and Carabus granulatus interstitialis form sperm bundles (spermatozeugmata) in which the heads of conventional insect sperm cells are embedded in the apical cap (spermatostyle), leaving the posterior flagella free. On the contrary, Pterostichus morio, Pterostichus melas, Pterostichus melanarius and Amara aulica form complex spermatozeugmata bearing conspicuous axial spermatostyles associated with lateral groups of sperm. Individual sperm cells are contained in chambers delimited by laminar extensions of the cortical region of the spermatostyle. Demetrias atricapillus shares the general spermatozeugma structure with the above species, but the anterior spermatostyle region has a different structure and posteriorly, the lateral groups of sperm are separated from the spermatostyle but remain connected to it by peduncles consisting of extensions of the cortical region of the spermatostyle. The sperm of the species examined in the study consist of a short, flat acrosomal cap and, with the exception of the Carabus species, show long nuclei which extend parallel to the axonemes, along the flagella. Two relatively small mitochondrial derivatives and two small accessory bodies flank the axoneme. These bodies become very thick in the posterior flagellar region of D. atricapillus. The study revealed different spermatozeugma models and different sperm organization in the Carabidae family.

The morphology and ultrastructure of salivary glands of Zoraptera (Insecta).

The salivary glands of two species of Zoraptera, Zorotypus caudelli and Zorotypus hubbardi, were examined and documented mainly using transmission electron microscopy (TEM). The results obtained for males and females of the two species are compared and functional aspects related to ultrastructural features are discussed. The salivary glands are divided into two regions: the secretory cell region and the long efferent duct, the latter with its distal end opening in the salivarium below the hypopharyngeal base. The secretory region consists of a complex of secretory cells provided with microvillated cavities connected by short ectodermal ducts to large ones, which are connected with the long efferent duct. The secretory cell cytoplasm contains a large system of rough endoplasmic reticulum and Golgi apparatus producing numerous dense secretions. The cells of the efferent duct, characterized by reduced cytoplasm and the presence of long membrane infoldings associated with mitochondria, are possibly involved in fluid uptaking from the duct lumen.

Spermiogenesis and sperm ultrastructure of Machilontus sp (Insecta: Archaeognatha) with phylogenetic consideration.

The sperm structure of the jumping bristletail Machilontus sp has been described. The species shares several sperm characteristics with other genera of the same order Archaeognatha. During late spermiogenesis the spermatid bends at half of its length with the two limbs closely apposed within the same plasma membrane. The sperm has a helicoidal bi-layered acrosome with a filamentous perforatorium and a long nucleus. The elongated flagellum consists of an axoneme with 9 accessory microtubules external to the 9+2, two rows of conventional mitochondria and two accessory bodies. The accessory bodies are located lateral to the axoneme and are probably responsible for the shifting of the accessory tubules in two opposite groups of 5 and 4 tubules, respectively. These sperm characteristics represent common traits of all Archaeognatha.

External macro- and micromorphology of the male of the stick insect Hermarchus leytensis (Insecta: Phasmatodea) with phylogenetic considerations.

External morphological features of adult males are described in the stick insect Hermarchus leytensis from the Philippines, a species belonging to the little-known euphasmatodean lineage Stephanacridini. Mouthparts are characterized by some likely specialized features: (1) a dentate dorsal cutting edge on the mandibles; (2) distinct differences in size and shape between the galeae; (3) absence of an apical field of trichomes on the galeae; and (4) lacinial setae not protruding from the mesal margin, which features three bearing-like protuberances. The latter character state represents a very unusual condition, not known in other phasmatodeans or even in polyneopteran insects. A distinctive characteristic of attachment devices is that each euplantula is divided into two separated pads with a smooth microstructure, as it also occurs in some members of the clade Schizodecema. Male terminalia exhibit character states previously unknown in Stephanacridini, including (1) a symmetrical type of vomer and (2) claspers equipped with ∼ 70 very minute ventral teeth on each thorn pad. Potential implications for the systematic placement of H. leytensis are discussed. The results also underline the importance of microanatomical investigations as source of substantial characters for future analyses on phasmatodean systematics.

Comparative morphology of spermatozoa and reproductive systems of zorapteran species from different world regions (Insecta, Zoraptera).

The male and female reproductive apparatus of Zorotypus magnicaudelli (Malaysia), Zorotypus huxleyi (Ecuador) and Zorotypus weidneri (Brazil) were examined and documented in detail. The genital apparatus and sperm of the three species show only minor differences. The testes are larger in Z. magnicaudelli. Z. huxleyi lacks the helical appendage in the accessory glands. A long cuticular flagellum is present in Z. magnicaudelli and in the previously studied Zorotypus caudelli like in several other species, whereas it is absent in Z. weidneri, Z. huxleyi, Zorotypus hubbardi, Zorotypus impolitus and Zorotypus guineensis. Characteristic features of the very similar sperm are the presence of: a) two dense arches above the axoneme; b) a 9 + 9+2 axoneme with detached subtubules A and B of doublets 1 and 6; c) the axonemal end degenerating with enlarging accessory tubules; d) accessory tubules with 17 protofilaments; e) three accessory bodies beneath the axoneme; and f) two mitochondrial derivatives of equal shape. The first characteristic (a) is unknown outside of Zoraptera and possibly autapomorphic. The sperm structure differs distinctly in Z. impolitus and Z. hubbardi, which produce giant sperm and possess a huge spermatheca. The presence of the same sperm type in species either provided with a sclerotized coiled flagellum in males or lacking this structure indicates that a different organization of the genital apparatus does not necessarily affect the sperm structure. The flagellum and its pouch has probably evolved within Zoraptera, but it cannot be excluded that it is a groundplan feature and was reduced several times. The fossil evidence and our findings suggest that distinct modifications in the genital apparatus occurred before the fragmentation of the Gondwanan landmass in the middle Cretaceous.