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Arthropod Structure & Development

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https://www.readbyqxmd.com/read/28450162/structure-and-ultrastructure-of-the-ovary-in-the-south-american-veturius-sinuatus-eschscholtz-coleoptera-passalidae
#1
Karen Salazar, Stéphane Boucher, José Eduardo Serrão
The morphoanatomy of the ovary in Veturius sinuatus (Eschscholtz) was studied by light and transmission electron microscopy. Data from the female gonad of this species provides more extended and precise knowledge regarding the organization of the ovary in Passalidae. Ovaries are composed of a pair of long telotrophic meroistic ovarioles, with some differences compared to the bauplan of this ovary type in Polyphaga (Coleoptera). The terminal filament has an enlarged proximal region with irregularly shaped cells in apparent degeneration process embedded in a membranous system...
April 24, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28438518/testicular-spermatogenesis-and-sperm-morphology-in-martarega-bentoi-heteroptera-notonectidae
#2
Ademária M Novais, Glenda Dias, José Lino-Neto
The testicular, spermatogenesis and sperm morphology of the backswimmer Martarega bentoi was described using light and transmission electron microscopy. In this species, a pair of testes, two deferent ducts, two different pairs of accessory glands, and an ejaculatory duct form the male reproductive system. Each testis consists of two testicular follicles, which are arranged side by side in snail shape. The follicles are filled with cysts at different stages of spermatogenesis, but in the same cyst the germ cells (up to 64) are in the same stage...
April 21, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28435074/ultrastructure-of-male-accessory-glands-in-the-scorpionfly-sinopanorpa-tincta-nav%C3%A3-s-1931-mecoptera-panorpidae
#3
Qi-Hui Lyu, Bao-Zhen Hua
The ultrastructure of male reproductive accessory glands was investigated in the scorpionfly Sinopanorpa tincta (Navás, 1931) (Mecoptera: Panorpidae) using light and transmission electron microscopy. The male accessory glands comprise one pair of mesodermal glands (mesadenia) and six pairs of ectodermal glands (ectadenia). The former opens into the vasa deferentia and the latter into the ejaculatory sac. The mesadenia consist of a mono-layered elongated columnar epithelium, the cells of which are highly microvillated and extrude secretory granules by means of merocrine mechanisms...
April 20, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28373032/comparative-morphology-of-the-prothoracic-leg-in-heliconian-butterflies-tracing-size-allometry-podite-fusions-and-losses-in-ontogeny-and-phylogeny
#4
Gilson R P Moreira, Denis S Silva, Gislene L Gonçalves
Prothoracic legs of heliconian butterflies (Nymphalidae, Heliconiinae, Heliconiini) are reduced in size compared to mesothoracic and metathoracic legs. They have no apparent function in males, but are used by females for drumming on host plants, a behavior related to oviposition site selection. Here, taking into account all recognized lineages of heliconian butterflies, we described their tarsi using optical and scanning electron microscopy and searched for podite fusions and losses, and analyzed allometry at the static, ontogenetic and phylogenetic levels...
April 20, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28344111/no-sight-no-smell-brain-anatomy-of-two-amphipod-crustaceans-with-different-lifestyles
#5
Till Ramm, Gerhard Scholtz
The brain anatomy of Niphargus puteanus and Orchestia cavimana, two amphipod species with different lifestyles, has been studied using a variety of recent techniques. The general aspects of the brain anatomy of both species correspond to those of other malacostracans. However, both species lack hemiellipsoid bodies. Furthermore, related to their lifestyle certain differences have been observed. The aquatic subterranean species N. puteanus lacks eye structures, the optic nerve, and the two outer optic neuropils lamina and medulla...
April 20, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28347859/the-sensory-arrays-of-the-ant-temnothorax-rugatulus
#6
Fiorella Ramirez-Esquivel, Nicole E Leitner, Jochen Zeil, Ajay Narendra
Individual differences in response thresholds to task-related stimuli may be one mechanism driving task allocation among social insect workers. These differences may arise at various stages in the nervous system. We investigate variability in the peripheral nervous system as a simple mechanism that can introduce inter-individual differences in sensory information. In this study we describe size-dependent variation of the compound eyes and the antennae in the ant Temnothorax rugatulus. Head width in T. rugatulus varies between 0...
April 12, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28365228/the-thoracic-morphology-of-the-wingless-dune-cricket-comicus-calcaris-orthoptera-schizodactylidae-novel-apomorphic-characters-for-the-group-and-adaptations-to-sand-desert-environments
#7
Fanny Leubner, Sven Bradler, Benjamin Wipfler
Schizodactylidae, splay-footed or dune crickets, represents a distinct lineage among the highly diverse orthopteran subgroup Ensifera (crickets, katydids and allies). Only two extant genera belong to the Schizodactylidae: the winged Eurasian genus Schizodactylus, whose ecology and morphology is well documented, and the wingless South African Comicus, for which hardly any studies providing morphological descriptions have been conducted since its taxonomic description in 1888. Based on the first in-depths study of the skeletomuscular system of the thorax of Comicus calcarisIrish 1986, we provide information on some unique characteristics of this character complex in Schizodactylidae...
March 29, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28163192/sperm-ultrastructure-of-shrimp-from-family-penaeidae-crustacea-dendrobranchiata-in-a-phylogenetic-context
#8
Tavani Rocha Camargo, Natalia Rossi, Antonio L Castilho, Rogério C Costa, Fernando L Mantelatto, Fernando José Zara
We describe the sperm ultrastructure of six penaeid species, including at least one member of each tribe (Penaeini, Parapenaeini and Trachypenaeini). Fragments of the vas deferens of the Penaeidae Farfantepenaeus brasiliensis, Farfantepenaeus paulensis, Litopenaeus schmitti, Parapenaeus americanus, Rimapenaeus constrictus and Xiphopenaeus kroyeri were fixed and processed according to the routine for transmission electron microscopy. The morphological results were contextualized in an evolutionary perspective using molecular markers for the phylogenetic reconstruction of this group...
March 27, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28347860/ultrastructure-of-spermiogenesis-and-spermatozoa-in-marchalina-hellenica-gennadius-hemiptera-sternorrhyncha-marchalinidae
#9
R Dallai, Mercati D, S Gounari, F Paoli, P Lupetti
The spermiogenesis, the sperm structure and the sperm motility of Marchalina hellenica (Gennadius) were examined. In the early spermiogenesis a centriolar apparatus was identified, but this structure is not involved in the production of the sperm flagellum. As in other Coccoidea, the flagellar axoneme originates by the activity of the thickened tip of the numerous microtubules surrounding the nuclear anterior region close to the periphery of the cell. This region pushes against a narrow cytoplasmic layer, giving rise to a papilla...
March 24, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28254451/using-insects-to-drive-mobile-robots%C3%A2-%C3%A2-hybrid-robots-bridge-the-gap-between-biological-and-artificial-systems
#10
REVIEW
Noriyasu Ando, Ryohei Kanzaki
The use of mobile robots is an effective method of validating sensory-motor models of animals in a real environment. The well-identified insect sensory-motor systems have been the major targets for modeling. Furthermore, mobile robots implemented with such insect models attract engineers who aim to avail advantages from organisms. However, directly comparing the robots with real insects is still difficult, even if we successfully model the biological systems, because of the physical differences between them...
March 18, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28043917/stylet-biogenesis-in-bactericera-cockerelli-hemiptera-triozidae
#11
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...
March 18, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28302586/mantisbot-is-a-robotic-model-of-visually-guided-motion-in-the-praying-mantis
#12
Nicholas S Szczecinski, Andrew P Getsy, Joshua P Martin, Roy E Ritzmann, Roger D Quinn
Insects use highly distributed nervous systems to process exteroception from head sensors, compare that information with state-based goals, and direct posture or locomotion toward those goals. To study how descending commands from brain centers produce coordinated, goal-directed motion in distributed nervous systems, we have constructed a conductance-based neural system for our robot MantisBot, a 29 degree-of-freedom, 13.3:1 scale praying mantis robot. Using the literature on mantis prey tracking and insect locomotion, we designed a hierarchical, distributed neural controller that establishes the goal, coordinates different joints, and executes prey-tracking motion...
March 13, 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28302585/development-and-evolution-of-segmentation-assessed-by-geometric-morphometrics-the-centipede-strigamia-maritima-as-a-case-study
#13
Yoland Savriama, Sylvain Gerber, Matteo Baiocco, Vincent Debat, Giuseppe Fusco
Using the centipede model species Strigamia maritima as a subject of study, we illustrate the potential of geometric morphometrics for investigating the development and evolution of segmentation, with a specific focus on post-embryonic segmental patterning. We show how these techniques can contribute detailed descriptive data for comparative purposes, but also precious information on some features of the developmental system that are considered relevant for the evolvability of a segmented body architecture, such as developmental stability and canalization...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/28235577/introduction-the-evolution-of-segmentation
#14
EDITORIAL
Alessandro Minelli
No abstract text is available yet for this article.
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27989966/origin-and-evolution-of-the-panarthropod-head-a-palaeobiological-and-developmental-perspective
#15
REVIEW
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...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27888167/delta-notch-signalling-in-segmentation
#16
REVIEW
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...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27725256/segmentation-in-tardigrada-and-diversification-of-segmental-patterns-in-panarthropoda
#17
REVIEW
Frank W Smith, Bob Goldstein
The origin and diversification of segmented metazoan body plans has fascinated biologists for over a century. The superphylum Panarthropoda includes three phyla of segmented animals-Euarthropoda, Onychophora, and Tardigrada. This superphylum includes representatives with relatively simple and representatives with relatively complex segmented body plans. At one extreme of this continuum, euarthropods exhibit an incredible diversity of serially homologous segments. Furthermore, distinct tagmosis patterns are exhibited by different classes of euarthropods...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27725255/a-molecular-view-of-onychophoran-segmentation
#18
Ralf Janssen
This paper summarizes our current knowledge on the expression and assumed function of Drosophila and (other) arthropod segmentation gene orthologs in Onychophora, a closely related outgroup to Arthropoda. This includes orthologs of the so-called Drosophila segmentation gene cascade including the Hox genes, as well as other genetic factors and pathways involved in non-drosophilid arthropods. Open questions about and around the topic are addressed, such as the definition of segments in onychophorans, the unclear regulation of conserved expression patterns downstream of non-conserved factors, and the potential role of mesodermal patterning in onychophoran segmentation...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27720841/linking-gene-regulation-to-cell-behaviors-in-the-posterior-growth-zone-of-sequentially-segmenting-arthropods
#19
REVIEW
Terri A Williams, Lisa M Nagy
Virtually all arthropods all arthropods add their body segments sequentially, one by one in an anterior to posterior progression. That process requires not only segment specification but typically growth and elongation. Here we review the functions of some of the key genes that regulate segmentation: Wnt, caudal, Notch pathway, and pair-rule genes, and discuss what can be inferred about their evolution. We focus on how these regulatory factors are integrated with growth and elongation and discuss the importance and challenges of baseline measures of growth and elongation...
May 2017: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27240897/segmentation-and-tagmosis-in-chelicerata
#20
Jason A Dunlop, James C Lamsdell
Patterns of segmentation and tagmosis are reviewed for Chelicerata. Depending on the outgroup, chelicerate origins are either among taxa with an anterior tagma of six somites, or taxa in which the appendages of somite I became increasingly raptorial. All Chelicerata have appendage I as a chelate or clasp-knife chelicera. The basic trend has obviously been to consolidate food-gathering and walking limbs as a prosoma and respiratory appendages on the opisthosoma. However, the boundary of the prosoma is debatable in that some taxa have functionally incorporated somite VII and/or its appendages into the prosoma...
May 2017: Arthropod Structure & Development
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