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Arthropod Structure & Development

Dnyaneshwar Doke, Rashmi Morey, Neelesh Dahanukar, Sameer M Padhye, Shruti V Paripatyadar
Despite being one of the dominant groups in freshwater ecosystems, morphological and ontogenetic studies on aquatic Hemiptera have received little attention in the Oriental region. We present the ontogenetic trajectory and allometry of the widespread Oriental belostomatid species, Diplonychus rusticus (Fabricius) for the first time. We have measured nine different morphological variables throughout the growth of the bug using both field captured and laboratory reared specimens. Our results suggest that the developmental instars can be distinguished by the size variables, as seen in the Principal Component Analysis...
January 5, 2017: Arthropod Structure & Development
Johannes Strauß
Multiple mechanosensory organs form the subgenual organ complex in orthopteroid insects, located in the proximal tibia. In several Ensifera (Orthoptera), a small chordotonal organ, the so-called accessory organ, is the most posterior part of this sensory complex. In order to document the presence of this accessory organ among the Ensifera, the chordotonal sensilla and their innervation in the posterior tibia of two species of Jerusalem crickets (Stenopelmatidae: Stenopelmatus) is described. The sensory structures were stained by axonal tracing...
January 4, 2017: Arthropod Structure & Development
Rustem Uzbekov, Julien Burlaud-Gaillard, Anastasiia S Garanina, Christophe Bressac
The spermatozoon of the parasitoid wasp Cotesia congregata is an extremely short gamete measuring less than 7 μm; it is as yet the shortest flagellated sperm to be identified. The mature sperm consists of an acrosome, surrounded by an extra cellular coat, a condensed nucleus, two uncoiled mitochondrial derivatives and a short axoneme. Testes of young adults contain a continuum of differentiation stages. Initially, the flagellum is approximately 5 μm long. It conserves its length in round, elongated and mature spermatids, but is reduced to less than 3 μm in mature spermatozoa...
January 4, 2017: Arthropod Structure & Development
Ralph Rübsam, Jürgen Büning
Telotrophic meroistic insect ovaries are assigned to four different types. The Sialis type is found in Sialidae (Megaloptera), Raphidioptera and a coleopteran subgroup (Myxophaga: Hydroscaphidae). King and Büning (1985) proposed a hypothetical model for the development of this ovariole type; however, a detailed description of ovarian development in Sialis was missing so far. Using light and electron microscopy, we investigated developing ovaries of Sialis flavilatera starting in the 10th month of the biennial larval phase until adulthood...
January 4, 2017: Arthropod Structure & Development
Sarah Hayer, Stephanie Köhnk, Christoph D Schubart, Susann Boretius, Stanislav N Gorb, Dirk Brandis
Because of the poor knowledge of the morphology of the female reproductive organs of most brachyuran crabs, this study investigated two Atlantic representatives of the family Leucosiidae, Ilia nucleus (Linnaeus, 1758) and Persephona mediterranea (Herbst, 1794), using histological methods and magnetic resonance imaging (MRI). While the vagina conforms to the concave type, the arrangement of the two chambers of the seminal receptacle differs strongly from that of other eubrachyuran sperm storage organs. Both chambers are oriented laterally within the crab's body...
January 3, 2017: Arthropod Structure & Development
Joseph M Cicero
The discovery of 'Ca. Liberibacter solanacearum', causal agent of certain solanaceous and apiaceous crop diseases, inside the functional (intrastadial) and pharate stylet anatomy of the potato psyllid prompted elucidation of the mechanism of stylet replacement as a novel exit portal in the transmission pathway. In Hemiptera, presumptive (formative) stylets, secreted during consecutive pharate instars, replace functional stylets lost with the exuviae. In potato psyllids, each functional stylet has a hollow core filled with a cytology that extends out of the core to form a hemispherical aggregate of cells, the 'end-cap', somewhat resembling a golf ball on a tee...
December 30, 2016: Arthropod Structure & Development
Guilherme Gainett, Peter Michalik, Carsten H G Müller, Gonzalo Giribet, Giovanni Talarico, Rodrigo H Willemart
Harvestmen (Arachnida, Opiliones) are especially dependent on chemical cues and are often regarded as animals that rely mainly on contact chemoreception. Information on harvestman sensilla is scarce when compared to other arachnid orders, especially concerning internal morphology. Using scanning (SEM) and transmission (TEM) electron microscopy, we investigated tarsal sensilla on the distal tarsomeres (DT) of all leg pairs in Heteromitobates discolor (Laniatores, Gonyleptidae). Furthermore, we explored the typological diversity of sensilla present on the DT I and II in members of the suborder Laniatores, which include two thirds of the formally described opilionid fauna, using species from 17 families representing all main laniatorian lineages...
December 22, 2016: Arthropod Structure & Development
Klaus Reinhardt, Hans Georg Breunig, Karsten König
The decay time of the fluorescence of excited molecules, called fluorescence lifetime, can provide information about the cuticle composition additionally to widely used spectral characteristics. We compared autofluorescence lifetimes of different cuticle regions in the copulatory organ of females of the bedbug, Cimex lectularius. After two-photon excitation at 720 nm, regions recently characterised as being rich in resilin showed a longer bimodal distribution of the mean autofluorescence lifetime τm (tau-m) at 0...
December 22, 2016: Arthropod Structure & Development
Julia V A Figueiredo, André L P Perondini, Denise Selivon
The inner chorion structure of Anastrepha eggs from 16 species of various infrageneric taxonomic groups is described by scanning and transmission electron microscopy. The layers of the chorion, the outer egg membrane, are structurally similar. Furthermore, an additional trabecular layer (ATL) that exists in some species, together with other characteristics, facilitates the recognition of four patterns of chorion structuring: Pattern I, in which the ATL layer is absent, is found in Anastrephaamita, the Anastrepha fraterculus complex, Anastrepha obliqua, Anastrepha sororcula, Anastrephasuspensa and Anastrephazenildae (fraterculus group), and Anastrephabistrigata and Anastrephastriata (striata group); Pattern II in Anastrephaserpentina (serpentina group), Anastrephagrandis (grandis group) and Anastrephapseudoparallela (pseudoparallela group), in which the ATL presents large open spaces with pillars; Pattern III, found in Anastrephaconsobrina (pseudoparallela group), in which the ATL is composed of round cavities; and Pattern IV, found in Anastrephaalveata and Anastrephapickeli (spatulata group), where the large ATL cavities are reticulated...
December 22, 2016: Arthropod Structure & Development
Susanne Randolf, Dominique Zimmermann, Ulrike Aspöck
External and internal head structures of adult Coniopteryx pygmaea Enderlein, 1906, one of the smallest known lacewings, are described in detail for the first time. Possible effects of miniaturization and two hypotheses on the phylogenetic position of Coniopterygidae are evaluated and compared with data from literature. Several convergent modifications in C. pygmaea and other miniaturized insect species are outlined, e.g., a relative increase in the size of the brain, simplification of the tracheal system with respect to the number of tracheae, and reduction of the number of ommatidia and diameter of the facets...
December 21, 2016: Arthropod Structure & Development
Yiwen Wang, Renata Zuber, Annette Laudahn, Jürgen Berger, Bernard Moussian
The body surface of insects usually carries cuticular hairs. Commonly, important functions of these structures are to prevent drowning and to defend against predators. Here, we report on our studies on hairs at the surface of larvae of the ant species Camponotus floridanus and Camponotus sericeiventris. First, we present data supporting the hypothesis that anti-drowning properties of the surface might rely on cuticular hairs. Second, we show that especially in young larvae body hairs serve as attachment and interlocking devices mediating clumping of larvae facilitating transport by workers...
December 20, 2016: Arthropod Structure & Development
Bo-Kai Liao, Andrew C Oates
Modular body organization is found widely across multicellular organisms, and some of them form repetitive modular structures via the process of segmentation. It's vastly interesting to understand how these regularly repeated structures are robustly generated from the underlying noise in biomolecular interactions. Recent studies from arthropods reveal similarities in segmentation mechanisms with vertebrates, and raise the possibility that the three phylogenetic clades, annelids, arthropods and chordates, might share homology in this process from a bilaterian ancestor...
December 19, 2016: Arthropod Structure & Development
Bibiana Ospina-Rozo, Manu Forero-Shelton, Jorge Molina
The antennae of Insecta consist of two basal segments and the distal annulated flagellum lacking intrinsic muscles. Non-muscular joints are important to preserve the flexibility and structure of the long Heteropteran antennae which bears an intersegmental nodule on each non-muscular joint. Little is known about their properties or function. Here we characterize the structure and postembryonic development of the non-muscular joints of Rhodnius prolixus antennae. Using Scanning Electron Microscopy, we tracked the changes in shape and size of both intersegmental nodules during the course of the hemimetabolous insect life cycle...
December 17, 2016: Arthropod Structure & Development
Javier Ortega-Hernández, Ralf Janssen, Graham E Budd
The panarthropod head represents a complex body region that has evolved through the integration and functional specialization of the anterior appendage-bearing segments. Advances in the developmental biology of diverse extant organisms have led to a substantial clarity regarding the relationships of segmental homology between Onychophora (velvet worms), Tardigrada (water bears), and Euarthropoda (e.g. arachnids, myriapods, crustaceans, hexapods). The improved understanding of the segmental organization in panarthropods offers a novel perspective for interpreting the ubiquitous Cambrian fossil record of these successful animals...
December 17, 2016: Arthropod Structure & Development
Doris L Maurer, Tobias Kohl, Michael J Gebhardt
The stick insect Peruphasma schultei stands out from other insects by its deep matt black cuticle. We tested whether the appearance of P. schultei is due to microstructures of the cuticle, a phenomenon that has recently been described for the velvet black scales of the Gaboon viper. The shiny black stick insect Anisomorpha paromalus served as a control. We found that the P. schultei cuticle is characterised by two different types of microstructures, tall elevations with a maximum size of 18 μm and small structures with a height of 4 μm...
December 17, 2016: Arthropod Structure & Development
Philip O M Steinhoff, Andy Sombke, Jannis Liedtke, Jutta M Schneider, Steffen Harzsch, Gabriele Uhl
Jumping spiders are known for their extraordinary cognitive abilities. The underlying nervous system structures, however, are largely unknown. Here, we explore and describe the anatomy of the brain in the jumping spider Marpissa muscosa (Clerck, 1757) by means of paraffin histology, X-ray microCT analysis and immunohistochemistry as well as three-dimensional reconstruction. In the prosoma, the CNS is a clearly demarcated mass that surrounds the esophagus. The anteriormost neuromere, the protocerebrum, comprises nine bilaterally paired neuropils, including the mushroom bodies and one unpaired midline neuropil, the arcuate body...
December 17, 2016: Arthropod Structure & Development
Eoin Parle, Jan-Henning Dirks, David Taylor
The exoskeleton of an insect can contain countless specializations across an individual, across developmental stages, and across the class Insecta. Hence, the exoskeleton's building material cuticle must perform a vast variety of functions. Cuticle displays a wide range of material properties which are determined by several known factors: the amount and orientation of the chitin fibres, the constituents and degree of cross-linking and hydration of the protein matrix, the relative amounts of exo- and endocuticle, and the shape of the structures themselves...
December 8, 2016: Arthropod Structure & Development
Polona Mrak, Urban Bogataj, Jasna Štrus, Nada Žnidaršič
The crustacean cuticle is a chitin-based extracellular matrix, produced in general by epidermal cells and ectodermally derived epithelial cells of the digestive tract. Cuticle morphogenesis is an integrative part of embryonic and postembryonic development and it was studied in several groups of crustaceans, but mainly with a focus on one selected aspect of morphogenesis. Early studies were focused mainly on in vivo or histological observations of embryonic or larval molt cycles and more recently, some ultrastructural studies of the cuticle differentiation during development were performed...
December 2, 2016: Arthropod Structure & Development
Aleksei A Miroliubov
Rhizocephalan parasites have a peculiar life cycle, and their adults lost almost all traits found usually in Crustacea. Despite some data on anatomy and ultrastructure of interna of Peltogastridae, some crucial aspects of morphology are still unknown. For example, there is only one mentioning of myocytes found in interna of Rhizophalans (Sacculina carcini). So we aimed at studying the muscular system of the interna of Peltogaster paguri using serial histological sectioning and fluorescent staining (TRITC-labelled phalloidin) with confocal microscopy...
November 18, 2016: Arthropod Structure & Development
Yanina-Yasmin Pesch, Dietmar Riedel, Matthias Behr
The architecture of the outer body wall cuticle is fundamental to protect arthropods against invading pathogens and numerous other harmful stresses. Such robust cuticles are formed by parallel running chitin microfibrils. Molting and also local wounding leads to dynamic assembly and disassembly of the chitin-matrix throughout development. However, the underlying molecular mechanisms that organize proper chitin-matrix formation are poorly known. Recently we identified a key region for cuticle thickening at the apical cell surface, the cuticle assembly zone, where Obstructor-A (Obst-A) coordinates the formation of the chitin-matrix...
November 7, 2016: Arthropod Structure & Development
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