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  Subjects -> BIOLOGY (Total: 2985 journals)
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BIOLOGY (1422 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 20)
Achievements in the Life Sciences     Open Access   (Followers: 4)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 20)
Acta Biologica Colombiana     Open Access   (Followers: 6)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 4)
Acta Biologica Sibirica     Open Access  
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Acta Biotheoretica     Hybrid Journal   (Followers: 5)
Acta Chiropterologica     Full-text available via subscription   (Followers: 6)
acta ethologica     Hybrid Journal   (Followers: 4)
Acta Limnologica Brasiliensia     Open Access   (Followers: 3)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Musei Silesiae, Scientiae Naturales : The Journal of Silesian Museum in Opava     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 9)
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Advances in Virus Research     Full-text available via subscription   (Followers: 5)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 6)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 1)
Ageing Research Reviews     Hybrid Journal   (Followers: 7)
Aging Cell     Open Access   (Followers: 9)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
AJP Cell Physiology     Full-text available via subscription   (Followers: 13)
AJP Endocrinology and Metabolism     Full-text available via subscription   (Followers: 23)
AJP Lung Cellular and Molecular Physiology     Full-text available via subscription   (Followers: 3)
Al-Kauniyah : Jurnal Biologi     Open Access  
Alasbimn Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Biology Teacher     Full-text available via subscription   (Followers: 12)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 10)
American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Human Biology     Hybrid Journal   (Followers: 12)
American Journal of Medical and Biological Research     Open Access   (Followers: 5)
American Journal of Plant Sciences     Open Access   (Followers: 19)
American Journal of Primatology     Hybrid Journal   (Followers: 15)
American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 64)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 7)
Anatomical Science International     Hybrid Journal   (Followers: 2)
Animal Cells and Systems     Hybrid Journal   (Followers: 4)
Annales de Limnologie - International Journal of Limnology     Hybrid Journal   (Followers: 1)
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales UMCS, Biologia     Open Access   (Followers: 1)
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Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18)
Annals of Human Biology     Hybrid Journal   (Followers: 4)
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 17)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 25)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 37)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 18)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 23)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antibiotics     Open Access   (Followers: 8)
Antioxidants     Open Access   (Followers: 4)
Antioxidants & Redox Signaling     Hybrid Journal   (Followers: 8)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apidologie     Hybrid Journal   (Followers: 4)
Apmis     Hybrid Journal   (Followers: 1)
APOPTOSIS     Hybrid Journal   (Followers: 8)
Applied Bionics and Biomechanics     Open Access   (Followers: 8)
Applied Vegetation Science     Full-text available via subscription   (Followers: 9)
Aquaculture Environment Interactions     Open Access   (Followers: 2)
Aquaculture International     Hybrid Journal   (Followers: 22)
Aquaculture Reports     Open Access   (Followers: 3)
Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society     Open Access   (Followers: 6)
Aquatic Biology     Open Access   (Followers: 4)
Aquatic Ecology     Hybrid Journal   (Followers: 30)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 13)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 19)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biomedical Sciences     Open Access   (Followers: 7)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Archives of Natural History     Hybrid Journal   (Followers: 7)
Archives of Oral Biology     Hybrid Journal   (Followers: 2)
Archives of Virology     Hybrid Journal   (Followers: 5)
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arquivos do Museu Dinâmico Interdisciplinar     Open Access  
Arthropod Structure & Development     Hybrid Journal   (Followers: 2)
Arthropods     Open Access   (Followers: 1)
Artificial DNA: PNA & XNA     Hybrid Journal   (Followers: 2)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 1)
Asian Journal of Biodiversity     Open Access   (Followers: 5)
Asian Journal of Biological Sciences     Open Access   (Followers: 3)
Asian Journal of Cell Biology     Open Access   (Followers: 5)
Asian Journal of Developmental Biology     Open Access   (Followers: 2)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 2)
Asian Journal of Nematology     Open Access   (Followers: 3)
Asian Journal of Poultry Science     Open Access   (Followers: 4)
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 5)
Autophagy     Hybrid Journal   (Followers: 2)
Avian Biology Research     Full-text available via subscription   (Followers: 3)
Avian Conservation and Ecology     Open Access   (Followers: 7)
Bacteriology Journal     Open Access   (Followers: 2)
Bacteriophage     Full-text available via subscription   (Followers: 3)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Plant Taxonomy     Open Access  
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Berita Biologi     Open Access   (Followers: 1)
Between the Species     Open Access   (Followers: 1)
Bio Tribune Magazine     Hybrid Journal  
BIO Web of Conferences     Open Access  
BIO-Complexity     Open Access  
Bio-Grafía. Escritos sobre la Biología y su enseñanza     Open Access  
Bioanalytical Reviews     Hybrid Journal   (Followers: 2)
Biocatalysis and Biotransformation     Hybrid Journal   (Followers: 6)
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 14)
Biochimie     Hybrid Journal   (Followers: 7)
BioControl     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodemography and Social Biology     Hybrid Journal   (Followers: 1)
Biodiversidad Colombia     Open Access  
Biodiversity : Research and Conservation     Open Access   (Followers: 26)
Biodiversity and Natural History     Open Access   (Followers: 5)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     Open Access  
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Bioelectromagnetics     Hybrid Journal   (Followers: 1)
Bioenergy Research     Hybrid Journal   (Followers: 2)
Bioengineering and Bioscience     Open Access   (Followers: 1)
BioEssays     Hybrid Journal   (Followers: 10)
Bioethics     Hybrid Journal   (Followers: 14)
BioéthiqueOnline     Open Access  
Biofabrication     Hybrid Journal   (Followers: 3)
Biogeosciences (BG)     Open Access   (Followers: 10)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 1)
Bioinformatics     Hybrid Journal   (Followers: 236)
Bioinformatics and Biology Insights     Open Access   (Followers: 14)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 6)
Biointerphases     Open Access   (Followers: 1)
Biojournal of Science and Technology     Open Access  
Biologia     Hybrid Journal  
Biologia on-line : Revista de divulgació de la Facultat de Biologia     Open Access  
Biological Bulletin     Partially Free   (Followers: 4)
Biological Control     Hybrid Journal   (Followers: 5)
Biological Invasions     Hybrid Journal   (Followers: 16)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 14)
Biological Letters     Open Access   (Followers: 4)
Biological Procedures Online     Open Access  
Biological Psychiatry     Hybrid Journal   (Followers: 41)
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Biological Rhythm Research     Hybrid Journal   (Followers: 2)
Biological Theory     Hybrid Journal   (Followers: 1)
Biological Trace Element Research     Hybrid Journal  
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Biologics: Targets & Therapy     Open Access   (Followers: 1)
Biologie Aujourd'hui     Full-text available via subscription  
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 42)
Biologija     Open Access  
Biology     Open Access   (Followers: 5)
Biology and Philosophy     Hybrid Journal   (Followers: 16)
Biology Bulletin     Hybrid Journal   (Followers: 1)
Biology Bulletin Reviews     Hybrid Journal  
Biology Direct     Open Access   (Followers: 7)
Biology Letters     Full-text available via subscription   (Followers: 35)
Biology Methods and Protocols     Hybrid Journal  

        1 2 3 4 5 6 7 8 | Last

Journal Cover Arthropod Structure & Development
  [SJR: 0.983]   [H-I: 45]   [2 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1467-8039
   Published by Elsevier Homepage  [3042 journals]
  • Segmentation in Tardigrada and diversification of segmental patterns in
           Panarthropoda
    • Authors: Frank W. Smith; Bob Goldstein
      Pages: 328 - 340
      Abstract: Publication date: May 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 3
      Author(s): 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. At the other extreme, all tardigrades share a simple segmented body plan that consists of a head and four leg-bearing segments. The modular body plans of panarthropods make them a tractable model for understanding diversification of animal body plans more generally. Here we review results of recent morphological and developmental studies of tardigrade segmentation. These results complement investigations of segmentation processes in other panarthropods and paleontological studies to illuminate the earliest steps in the evolution of panarthropod body plans.

      PubDate: 2017-05-22T17:11:37Z
      DOI: 10.1016/j.asd.2016.10.005
       
  • Segmentation and tagmosis in Chelicerata
    • Authors: Jason A. Dunlop; James C. Lamsdell
      Pages: 395 - 418
      Abstract: Publication date: May 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 3
      Author(s): 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. Euchelicerata can be defined on having plate-like opisthosomal appendages, further modified within Arachnida. Total somite counts for Chelicerata range from a maximum of nineteen in groups like Scorpiones and the extinct Eurypterida down to seven in modern Pycnogonida. Mites may also show reduced somite counts, but reconstructing segmentation in these animals remains challenging. Several innovations relating to tagmosis or the appendages borne on particular somites are summarised here as putative apomorphies of individual higher taxa. We also present our observations within the concept of pseudotagma, whereby the true tagmata – the prosoma and opisthosoma – can be defined on a fundamental change in the limb series while pseudotagmata, such as the cephalosoma/proterosoma, are expressed as divisions in sclerites covering the body without an accompanying change in the appendages.

      PubDate: 2017-05-22T17:11:37Z
      DOI: 10.1016/j.asd.2016.05.002
       
  • Editorial
    • Authors: Alexander Steinbrecht; Nicholas Strausfeld
      First page: 1
      Abstract: Publication date: January 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 1
      Author(s): Alexander Steinbrecht, Nicholas Strausfeld


      PubDate: 2017-02-05T14:12:04Z
      DOI: 10.1016/j.asd.2017.01.003
       
  • The arthropod cuticle – A never-ending endeavor
    • Authors: Helge-Otto Fabritius; Bernard Moussian
      Pages: 2 - 3
      Abstract: Publication date: January 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 1
      Author(s): Helge-Otto Fabritius, Bernard Moussian


      PubDate: 2017-02-05T14:12:04Z
      DOI: 10.1016/j.asd.2017.01.004
       
  • Mineral in skeletal elements of the terrestrial crustacean Porcellio
           scaber: SRμCT of function related distribution and changes during the
           moult cycle
    • Authors: Andreas Ziegler; Frank Neues; Jiří Janáček; Felix Beckmann; Matthias Epple
      Pages: 63 - 76
      Abstract: Publication date: January 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 1
      Author(s): Andreas Ziegler, Frank Neues, Jiří Janáček, Felix Beckmann, Matthias Epple
      Terrestrial isopods moult first the posterior and then the anterior half of the body, allowing for storage and recycling of CaCO3. We used synchrotron-radiation microtomography to estimate mineral content within skeletal segments in sequential moulting stages of Porcellio scaber. The results suggest that all examined cuticular segments contribute to storage and recycling, however, to varying extents. The mineral within the hepatopancreas after moult suggests an uptake of mineral from the ingested exuviae. The total maximum loss of mineral was 46% for the anterior and 43% for the posterior cuticle. The time course of resorption of mineral and mineralisation of the new cuticle suggests storage and recycling of mineral in the posterior and anterior cuticle. The mineral in the anterior pereiopods decreases by 25% only. P. scaber has long legs and can run fast; therefore, a less mineralised and thus lightweight cuticle in pereiopods likely serves to lower energy consumption during escape behaviour. Differential demineralisation occurs in the head cuticle, in which the cornea of the complex eyes remains completely mineralised. The partes incisivae of the mandibles are mineralised before the old cuticle is demineralised and shed. Probably, this enables the animal to ingest the old exuviae after each half moult.
      Graphical abstract image

      PubDate: 2017-02-05T14:12:04Z
      DOI: 10.1016/j.asd.2016.05.004
       
  • Timing of autophagy and apoptosis during posterior silk gland degeneration
           in Bombyx mori
    • Authors: Aurora Montali; Davide Romanelli Silvia Cappellozza Annalisa Grimaldi Magda Eguileor
      Abstract: Publication date: Available online 16 June 2017
      Source:Arthropod Structure & Development
      Author(s): Aurora Montali, Davide Romanelli, Silvia Cappellozza, Annalisa Grimaldi, Magda de Eguileor, Gianluca Tettamanti
      Over the years, the silkworm, Bombyx mori, has been manipulated by means of chemical and genetic approaches to improve silk production both quantitatively and qualitatively. The silk is produced by the silk gland, which degenerates quickly once the larva has finished spinning the cocoon. Thus, interfering with this degeneration process could help develop new technologies aimed at ameliorating silk yield. To this end, in this work we studied the cell death processes that lead to the demise of the posterior silk gland of B. mori, directing in particular our attention to autophagy and apoptosis. We focused on this portion of the gland because it produces fibroin, the main component of the silk thread. By using multiple markers, we provide a morphological, biochemical and molecular characterization of the apoptotic and autophagic processes and define their timing in this biological setting. Our data demonstrate that the activation of both autophagy and apoptosis is preceded by a transcriptional rise in key regulatory genes. Moreover, while autophagy is maintained active for several days and progressively digests silk gland cells, apoptosis is only switched on at a very late stage of silk gland demise.
      Graphical abstract image

      PubDate: 2017-06-16T19:47:03Z
       
  • Transient leg deformations during eclosion out of a tight confinement: A
           comparative study on seven species of flies, moths, ants and bees
    • Authors: Leonid Frantsevich; Iryna Kozeretska; Yuriy Dubrovsky; Tetyana Markina; Iryna Shumakova; Stanislav Stukalyuk
      Abstract: Publication date: Available online 3 June 2017
      Source:Arthropod Structure & Development
      Author(s): Leonid Frantsevich, Iryna Kozeretska, Yuriy Dubrovsky, Tetyana Markina, Iryna Shumakova, Stanislav Stukalyuk
      Legs in dipteran pupae are tightly packed in a zigzag configuration. Changes in the shape or configuration of long podomeres during eclosion have been overlooked because they occur rapidly (in a few minutes) and the legs are hidden inside a tight opaque confinement: the puparium in the Cyclorrhapha, the obtect pupa in mosquitoes. We fixed insects at different times during eclosion and obtained a temporal description of changes in leg shape. At the start of eclosion in Calliphora vicina and Drosophila melanogaster, femora are buckled in between the joints. Later, the chain of podomeres straightened, pointing posterad. Initial deformation and further stretching were passive, exerted by forces external to the legs. The prerequisites for this are pliability of the tubular podomeres and anchoring of the tarsi to the confinement. Each femur was strongly crooked instead of buckled in the mosquito Aedes cantans. The site of bending shifted distad in the course of eclosion: a sort of peeling. In contrast, other insects (the moth Bombyx mori, the ants Formica polyctena and Formica rufa, the honey bee Apis mellifera) left their tight confinements without any change in the initial zigzag leg configuration and without transient deformations of initially straight femora and tibiae.
      Graphical abstract image

      PubDate: 2017-06-06T18:40:16Z
      DOI: 10.1016/j.asd.2017.05.002
       
  • Ultrastructure of male accessory glands in the scorpionfly Sinopanorpa
           tincta (Navás, 1931) (Mecoptera: Panorpidae)
    • Authors: Qi-Hui Lyu; Bao-Zhen Hua
      Abstract: Publication date: Available online 25 May 2017
      Source:Arthropod Structure & Development
      Author(s): 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. The epithelium of ectadenia consists of two types of cells: the large secretory cells and the thin duct-forming cells. These two types of cells that join with a cuticular duct constitute a functional glandular unit, corresponding to the class III glandular cell type of Noirot and Quennedey. The cuticular duct consists of a receiving canal and a conducting canal. The secretory granules were taken up by the receiving canal and then plunged into the lumen through the conducting canal.
      Graphical abstract image

      PubDate: 2017-05-27T17:52:45Z
      DOI: 10.1016/j.asd.2017.04.001
       
  • Structure and ultrastructure of the ovary in the South American Veturius
           sinuatus (Eschscholtz) (Coleoptera, Passalidae)
    • Authors: Karen Salazar; Stéphane Boucher; José Eduardo Serrão
      Abstract: Publication date: Available online 24 May 2017
      Source:Arthropod Structure & Development
      Author(s): 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 provide 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. Globular structures with amorphous content associated with interstitial cells are distributed throughout the tropharium. Trophocytes develop with the reduction of the plasma membrane between sibling nurse cells of each cluster. Previtellogenic oocytes have an irregular shape and various cytoplasmic prolongations. As oogenesis advances, a single prolongation in the anterior part of the oocyte extends to the tropharium. The ovary structure is comparable to that found in other American species of passalids, and further, the conformation of the terminal filament could be a plesiomorphic character of the family.
      Graphical abstract image

      PubDate: 2017-05-27T17:52:45Z
      DOI: 10.1016/j.asd.2017.03.007
       
  • Testicular, spermatogenesis and sperm morphology in Martarega bentoi
           (Heteroptera: Notonectidae)
    • Authors: Ademária M. Novais; Glenda Dias; José Lino-Neto
      Abstract: Publication date: Available online 18 May 2017
      Source:Arthropod Structure & Development
      Author(s): 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. At the end of spermatogenesis, the sperm cells are very long, with the flagellum measuring approximately 2500 μm in length, the nucleus only 19 μm, and the acrosome, with two distinct regions, 300 μm. The flagellum is composed of an axoneme, with a 9 + 9 + 2 microtubular pattern, and 2 asymmetric mitochondrial derivatives (MDs). These have the anterior ends inserted into two cavities at the nucleus base, exhibit two paracrystalline inclusions, and have bridges linking them to the axoneme. Few spermatozoa per cyst, asymmetry in size and shape of the MDs, as well as their insertion at the nuclear base are characteristics considered derived, and that differentiate the sperm of M. bentoi from those of the Nepomorpha, Belostomatidae and Nepidae.

      PubDate: 2017-05-22T17:11:37Z
      DOI: 10.1016/j.asd.2017.04.002
       
  • Advisory board/short GFA
    • Abstract: Publication date: May 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 3


      PubDate: 2017-05-22T17:11:37Z
       
  • Ultrastructure of spermiogenesis and spermatozoa in Marchalina hellenica
           (Gennadius) (Hemiptera: Sternorrhyncha, Marchalinidae)
    • Authors: Romano Dallai; David Mercati; Sofia Gounari; Francesco Paoli; Pietro Lupetti
      Abstract: Publication date: Available online 24 April 2017
      Source:Arthropod Structure & Development
      Author(s): Romano Dallai, David Mercati, Sofia Gounari, Francesco Paoli, Pietro 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. In this region a novel structure, consisting of a regular network of thin filaments, arranged orthogonally to the bundle of microtubules, is visible. The sperm flagellum consists of a series of about 260 microtubules, regularly arranged in rings around the axial nucleus. This latter extends in the middle part of the sperm length. As usual in scale insects, sperm form a bundle, which in M. hellenica is composed of 64 sperm cells, surrounded by somatic cyst cells. The sperm bundle has an helicoidal array, with a cap of dense material at its apex, lending the anterior and the posterior region of the sperm bundle with a different structural organization. This difference is responsible of the different speed gradient observed in the helical wave propagating along the sperm bundle.

      PubDate: 2017-04-26T15:28:16Z
      DOI: 10.1016/j.asd.2017.03.004
       
  • The thoracic morphology of the wingless dune cricket Comicus calcaris
           (Orthoptera: Schizodactylidae): Novel apomorphic characters for the group
           and adaptations to sand desert environments
    • Authors: Fanny Leubner; Sven Bradler; Benjamin Wipfler
      Abstract: Publication date: Available online 21 April 2017
      Source:Arthropod Structure & Development
      Author(s): 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-depth study of the skeletomuscular system of the thorax of Comicus calcaris Irish 1986, we provide information on some unique characteristics of this character complex in Schizodactylidae. They include a rigid connection of prospinasternite and mesosternum, a T-shaped mesospina, and a fused meso- and metasternum. Although Schizodactylidae is mainly characterized by group-specific anatomical traits of the thorax, its bifurcated profuca supports a closer relationship to the tettigonioid ensiferans, like katydids, wetas, and hump-winged crickets. Some specific features of the thoracic musculature of Comicus seem to be correlated to the skeletal morphology, e.g., due to the rigid connection of the tergites and pleurites in the pterothorax not a single direct flight muscle is developed. We show that many of the thoracic adaptations in these insects are directly related to their psammophilous way of life. These include a characteristic setation of thoracic sclerites that prevent sand grains from intrusion into vulnerable membranous areas, the striking decrease in size of the thoracic spiracles that reduces the respirational water loss, and a general trend towards a fusion of sclerites in the thorax.
      Graphical abstract image

      PubDate: 2017-04-26T15:28:16Z
      DOI: 10.1016/j.asd.2017.03.006
       
  • Comparative morphology of the prothoracic leg in heliconian butterflies:
           Tracing size allometry, podite fusions and losses in ontogeny and
           phylogeny
    • Authors: Gilson R.P. Moreira; Denis S. Silva; Gislene L. Gonçalves
      Abstract: Publication date: Available online 20 April 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Female tarsi were similar, club-shaped, showing from four to five tarsomeres, each bearing sensilla chaetica and trichodea. Male tarsi were cylindrical, formed from five (early diverging lineages) to one (descendant lineages) either partially or totally fused tarsomeres, all deprived of sensilla. Pretarsi were reduced in both sexes, in some species being either vestigial or absent. Tarsal lengths were smaller for males in almost all species. An abrupt decrease in size was detected for the prothoracic legs during molting to the last larval instar at both histological and morphometric levels. In both sexes, most allometric coefficients found at the population level for the prothoracic legs were negative compared to the mesothoracic leg and also to wings. Prothoracic tarsi decreased proportionally in size over evolutionary time; the largest and smallest values being found for nodes of the oldest and youngest lineages, respectively. Our results demonstrate that evolution of the prothoracic leg in heliconian butterflies has been based on losses and fusions of podites, in association with negative size allometry at static, ontogenetic and phylogenetic levels. These processes have been more pronounced in males. Our study provided further support to the hypothesis that evolution of these leg structures is driven by females, by changing their use from walking to drumming during oviposition site selection. In males the leg would have been selected against due to absence of function and thus progressively reduced in size, in association with podites fusions and lost.

      PubDate: 2017-04-26T15:28:16Z
      DOI: 10.1016/j.asd.2017.03.008
       
  • No sight, no smell? – Brain anatomy of two amphipod crustaceans
           with different lifestyles
    • Authors: Till Ramm; Gerhard Scholtz
      Abstract: Publication date: Available online 20 April 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Only partial remains of the lobula have been detected. In contrast to this, the central complex in the protocerebrum and the olfactory glomeruli in the deutocerebrum are well differentiated. The terrestrial species Orchestia cavimana shows a reduced first antenna, the absence of olfactory neuropils in the deutocerebrum, and a reduction of the olfactory globular tract. The characteristics in defining the hemiellipsoid bodies are critically discussed. Contradictions about presence or absence of this neuropil are due to different conceptualizations. A comparison with other crustaceans that live in dark environments reveal similar patterns of optic system reduction, but to different degrees following a centripetal pattern. Retaining the olfactory system seems a general problem of terrestrialization in crustaceans with the notable exception of terrestrial hermit crabs.
      Graphical abstract image

      PubDate: 2017-04-26T15:28:16Z
      DOI: 10.1016/j.asd.2017.03.003
       
  • The sensory arrays of the ant, Temnothorax rugatulus
    • Authors: Fiorella Ramirez-Esquivel; Nicole E. Leitner; Jochen Zeil; Ajay Narendra
      Abstract: Publication date: Available online 12 April 2017
      Source:Arthropod Structure & Development
      Author(s): 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 0.4 and 0.7 mm (2.6–3.8 mm body length). But despite this limited range of worker sizes we find sensory array variability. We find that the number of ommatidia and of some, but not all, antennal sensilla types vary with head width. The antennal array of T. rugatulus displays the full complement of sensillum types observed in other species of ants, although at much lower quantities than other, larger, studied species. In addition, we describe what we believe to be a new type of sensillum in hymenoptera that occurs on the antennae and on all body segments. T. rugatulus has apposition compound eyes with 45–76 facets per eye, depending on head width, with average lens diameters of 16.5 μm, rhabdom diameters of 5.7 μm and inter-ommatidial angles of 16.8°. The optical system of T. rugatulus ommatidia is severely under focussed, but the absolute sensitivity of the eyes is unusually high. We discuss the functional significance of these findings and the extent to which the variability of sensory arrays may correlate with task allocation.

      PubDate: 2017-04-19T14:52:03Z
      DOI: 10.1016/j.asd.2017.03.005
       
  • Mantisbot is a robotic model of visually guided motion in the praying
           mantis
    • Authors: Nicholas S. Szczecinski; Andrew P. Getsy; Joshua P. Martin; Roy E. Ritzmann; Roger D. Quinn
      Abstract: Publication date: Available online 28 March 2017
      Source:Arthropod Structure & Development
      Author(s): 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. In our controller, brain networks perceive the location of prey and predict its future location, store this location in memory, and formulate descending commands for ballistic saccades like those seen in the animal. The descending commands are simple, indicating only 1) whether the robot should walk or stand still, and 2) the intended direction of motion. Each joint's controller uses the descending commands differently to alter sensory-motor interactions, changing the sensory pathways that coordinate the joints' central pattern generators into one cohesive motion. Experiments with one leg of MantisBot show that visual input produces simple descending commands that alter walking kinematics, change the walking direction in a predictable manner, enact reflex reversals when necessary, and can control both static posture and locomotion with the same network.

      PubDate: 2017-03-28T13:51:22Z
      DOI: 10.1016/j.asd.2017.03.001
       
  • Sperm ultrastructure of shrimp from family Penaeidae (Crustacea:
           Dendrobranchiata) in a phylogenetic context
    • Authors: Tavani Rocha Camargo; Natalia Rossi; Antonio L. Castilho; Rogério C. Costa; Fernando L. Mantelatto; Fernando José Zara
      Abstract: Publication date: Available online 27 March 2017
      Source:Arthropod Structure & Development
      Author(s): 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. A phylogram was proposed by Bayesian inference based on 1007 bp of 33 sequences of the combined genes (16S rDNA and COI mtDNA) from 27 dendrobranchiate specimens. Our findings show that morphological differences in the sperm ultrastructures of members among the tribes of Penaeidae can be used as a baseline to understand their evolutionary relationships. Individuals from the Penaeini tribe show plesiomorphic characteristics in the sperm ultrastructure compared to the Trachypenaeini tribe from which they were derived, such as shrimp from family Sicyoniidae. The morphological complexity of the sperm of the different penaeid members corroborated with the genetic phylogeny, which showed different clades for each tribe and the close relationship with Sicyoniidae. The sperm features of the selected species studied here reflected their evolutionary history. These features confirm the previous phylogenetic hypothesis and question the monophyly of Penaeidae, which should be verified in the future with a more complete set of representative members of each tribe.

      PubDate: 2017-03-28T13:51:22Z
      DOI: 10.1016/j.asd.2017.01.006
       
  • Introduction: The evolution of segmentation
    • Authors: Alessandro Minelli
      Abstract: Publication date: Available online 23 March 2017
      Source:Arthropod Structure & Development
      Author(s): Alessandro Minelli


      PubDate: 2017-03-28T13:51:22Z
      DOI: 10.1016/j.asd.2017.02.002
       
  • Development and evolution of segmentation assessed by geometric
           morphometrics: The centipede Strigamia maritima as a case study
    • Authors: Yoland Savriama; Sylvain Gerber; Matteo Baiocco; Vincent Debat; Giuseppe Fusco
      Abstract: Publication date: Available online 22 March 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Morphometric analyses allow to separately investigate several sources of phenotypic variation along a segmented body axis, like constitutive and random segment heteronomy, both within and among individuals. Specifically, in S. maritima, the segmental pattern of ventral sclerite shapes mirrors that of their bilateral fluctuating asymmetry and among-individual variation in associating the most anterior and most posterior segments in diverging from the central ones. Also, among segments, there seems to be a correlation between fluctuating asymmetry and shape variation among individuals, suggesting that canalization and developmental stability are somehow associated. Overall, these associations might stem from a joint influence of the segmental position on the two processes of developmental buffering.
      Graphical abstract image

      PubDate: 2017-03-28T13:51:22Z
      DOI: 10.1016/j.asd.2017.03.002
       
  • Using insects to drive mobile robots — hybrid robots bridge the gap
           between biological and artificial systems
    • Authors: Noriyasu Ando; Ryohei Kanzaki
      Abstract: Publication date: Available online 18 March 2017
      Source:Arthropod Structure & Development
      Author(s): 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. We developed a hybrid robot to bridge the gap. This hybrid robot is an insect-controlled robot, in which a tethered male silkmoth (Bombyx mori) drives the robot in order to localize an odor source. This robot has the following three advantages: 1) from a biomimetic perspective, the robot enables us to evaluate the potential performance of future insect-mimetic robots; 2) from a biological perspective, the robot enables us to manipulate the closed-loop of an onboard insect for further understanding of its sensory–motor system; and 3) the robot enables comparison with insect models as a reference biological system. In this paper, we review the recent works regarding insect-controlled robots and discuss the significance for both engineering and biology.
      Graphical abstract image

      PubDate: 2017-03-21T13:14:18Z
      DOI: 10.1016/j.asd.2017.02.003
       
  • Stylet biogenesis in Bactericera cockerelli (Hemiptera: Triozidae)
    • Authors: Joseph M. Cicero
      Abstract: Publication date: Available online 18 March 2017
      Source:Arthropod Structure & Development
      Author(s): 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. A tightly folded mass of extremely thin cells, the ‘matrix’, occurs inside the end-cap. Micrograph interpretations indicate that during the pharate stage, the end-cap apolyses from the core and ‘deconstructs’ to release and expand the matrix into a long, coiled tube, the ‘atrium’. Cells that were in contact with the inner walls of the functional stylet core maintain their position at the apex of the tube, and secrete a new stylet, apex first, the growing length of which descends into the tube until completed. They then despool from the coils into their functional position as the exuviae is shed.
      Graphical abstract image

      PubDate: 2017-03-21T13:14:18Z
      DOI: 10.1016/j.asd.2016.12.007
       
  • Advisory board/short GFA
    • Abstract: Publication date: March 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 2


      PubDate: 2017-03-21T13:14:18Z
       
  • Formation of the acrosome complex in the bush cricket Gampsocleis gratiosa
           (Orthoptera: Tettigoniidae)
    • Authors: Cai Xia Su; Jie Chen; Fu Ming Shi; Ming Shen Guo; Yan Lin Chang
      Abstract: Publication date: Available online 3 March 2017
      Source:Arthropod Structure & Development
      Author(s): Cai Xia Su, Jie Chen, Fu Ming Shi, Ming Shen Guo, Yan Lin Chang
      The acrosome complex plays an indispensable role in the normal function of mature spermatozoa. However, the dynamic process of acrosome complex formation in insect remains poorly understood. Gampsocleis gratiosa Brunner von Wattenwyl possesses the typical characteristic of insect sperms, which is tractable in terms of size, and therefore was selected for the acrosome formation study in this report. The results show that acrosome formation can be divided into six phases: round, rotating, rhombic, cylindrical, transforming and mature phase, based on the morphological dynamics of acrosome complex and nucleus. In addition, the cytoskeleton plays a critical role in the process of acrosome formation. The results from this study indicate that: (1) glycoprotein is the major component of the acrosome proper; (2) the microfilament is one element of the acrosome complex, and may mediate the morphologic change of the acrosome complex; (3) the microtubules might also shape the nucleus and acrosome complex during the acrosome formation.

      PubDate: 2017-03-03T22:41:27Z
      DOI: 10.1016/j.asd.2017.01.002
       
  • The morphology and ultrastructure of salivary glands of Zoraptera
           (Insecta)
    • Authors: R. Dallai; D. Mercati; Y. Mashimo; R. Machida; R.G. Beutel
      Abstract: Publication date: Available online 2 March 2017
      Source:Arthropod Structure & Development
      Author(s): R. Dallai, D. Mercati, Y. Mashimo, R. Machida, R.G. Beutel
      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.

      PubDate: 2017-03-03T22:41:27Z
      DOI: 10.1016/j.asd.2017.02.001
       
  • Haltere morphology and campaniform sensilla arrangement across Diptera
    • Authors: Sweta Agrawal; David Grimaldi; Jessica L. Fox
      Abstract: Publication date: Available online 23 February 2017
      Source:Arthropod Structure & Development
      Author(s): Sweta Agrawal, David Grimaldi, Jessica L. Fox
      One of the primary specializations of true flies (order Diptera) is the modification of the hind wings into club-shaped halteres. Halteres are complex mechanosensory structures that provide sensory feedback essential for stable flight control via an array of campaniform sensilla at the haltere base. The morphology of these sensilla has previously been described in a small number of dipteran species, but little is known about how they vary across fly taxa. Using a synoptic set of specimens representing 42 families from all of the major infraorders of Diptera, we used scanning electron microscopy to map the gross and fine structures of halteres, including sensillum shape and arrangement. We found that several features of haltere morphology correspond with dipteran phylogeny: Schizophora generally have smaller halteres with stereotyped and highly organized sensilla compared to nematoceran flies. We also found a previously undocumented high variation of haltere sensillum shape in nematoceran dipterans, as well as the absence of a dorsal sensillum field in multiple families. Overall, variation in haltere sensillar morphology across the dipteran phylogeny provides insight into the evolution of a highly specialized proprioceptive organ and a basis for future studies on haltere sensory function.

      PubDate: 2017-02-24T20:56:12Z
      DOI: 10.1016/j.asd.2017.01.005
       
  • Linking gene regulation to cell behaviors in the posterior growth zone of
           sequentially segmenting arthropods
    • Authors: Terri A. Williams; Lisa M. Nagy
      Abstract: Publication date: Available online 15 February 2017
      Source:Arthropod Structure & Development
      Author(s): 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. We emphasize a perspective that integrates the genetic regulation of segment patterning with the cellular mechanisms of growth and elongation.

      PubDate: 2017-02-17T17:14:07Z
      DOI: 10.1016/j.asd.2016.10.003
       
  • A molecular view of onychophoran segmentation
    • Authors: Ralf Janssen
      Abstract: Publication date: Available online 15 February 2017
      Source:Arthropod Structure & Development
      Author(s): 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.

      PubDate: 2017-02-17T17:14:07Z
      DOI: 10.1016/j.asd.2016.10.004
       
  • Fine structure of the anterior median eyes of the funnel-web spider
           Agelena labyrinthica (Araneae: Agelenidae)
    • Authors: Wolfgang-D. Schröer
      Abstract: Publication date: Available online 10 February 2017
      Source:Arthropod Structure & Development
      Author(s): Wolfgang-D. Schröer
      Only few electron microscopic studies exist on the structure of the main eyes (anterior median eyes, AME) of web spiders. The present paper provides details on the anatomy of the AME in the funnel-web spider Agelena labyrinthica. The retina consists of two separate regions with differently arranged photoreceptor cells. Its central part has sensory cells with rhabdomeres on 2, 3, or 4 sides, whereas those of the ventral retina have only two rhabdomeres on opposite sides. In addition, the rhabdomeres of the ventral retina are arranged in a specific way: Whereas in the most ventral part they form long tangential rows, those towards the center are detached and are arranged radially. All sensory cells are wrapped by unpigmented pigment cell processes. In agelenid spiders the axons of the sensory cells exit from the middle of the cell body; their fine structure and course through the eye cup is described in detail. In the central part of the retina efferent nerve fibres were found forming synapses along the distal region of the receptor cells. A muscle is attached laterally to each eye cup that allows mainly rotational movements of the eyes. The optical performance (image resolution) of these main eyes with relatively few visual cells is discussed.

      PubDate: 2017-02-12T18:18:15Z
      DOI: 10.1016/j.asd.2017.01.001
       
  • Muscular system in interna of Peltogaster paguri (Rhizocephala:
           Peltogastridae)
    • Authors: Aleksei A. Miroliubov
      Abstract: Publication date: Available online 9 February 2017
      Source:Arthropod Structure & Development
      Author(s): 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 Rhizocephalans (Sacculina carcini). So we aimed at studying the muscular system of the interna of Peltogaster paguri using serial histological sectioning and fluorescent staining (TRITC-labeled phalloidin) with confocal microscopy. Within the wall of the main trunk we found striated muscular fibers. The majority of these fibers form a unidirectional single spiral. There are additional small fibers that connect the coils of the large spiral. The density of muscular fibers is highest near the externa stalk, and the number of muscle fibers decreases towards the distal part of the main trunk. We suggest that such a muscular system could provide peristaltic movements of the main trunk and the transport of nutrients through the interna.

      PubDate: 2017-02-12T18:18:15Z
      DOI: 10.1016/j.asd.2016.11.005
       
  • Comparative study of the morphology of the female seminal receptacles of
           Ilia nucleus and Persephona mediterranea (Decapoda, Brachyura,
           Leucosiidae)
    • Authors: Sarah Hayer; Stephanie Köhnk; Christoph D. Schubart; Susann Boretius; Stanislav N. Gorb; Dirk Brandis
      Abstract: Publication date: Available online 8 February 2017
      Source:Arthropod Structure & Development
      Author(s): 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. This is in contrast to the dorso-ventral orientation described in most other known brachyuran crabs. The lateral chamber is covered by cuticle, whereas the medial chamber is covered by a holocrine glandular epithelium. The oviduct connection is located ventrally, posterior to the vagina. The oviduct orifice is characterized by a transition from the epithelium lining the oviduct to the seminal receptacle's holocrine glandular epithelium. Moreover, muscle fibres are attached to the oviduct orifice and to the sternal cuticle. This musculature can be interpreted as an important feature in the fertilization and egg-laying process by supporting and controlling the inflow of eggs into the seminal receptacle lumen. The results of this study are compared to the morphology of the seminal receptacle of another leucosiid crab, Ebalia tumefacta (Montagu, 1808), and to those of other known eubrachyuran crabs.

      PubDate: 2017-02-12T18:18:15Z
      DOI: 10.1016/j.asd.2016.12.006
       
  • Head anatomy of adult Coniopteryx pygmaea Enderlein, 1906: Effects of
           miniaturization and the systematic position of Coniopterygidae (Insecta:
           Neuroptera)
    • Authors: Susanne Randolf; Dominique Zimmermann; Ulrike Aspöck
      Abstract: Publication date: Available online 6 February 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Further, the ocular ridge is bell-shaped and countersunk into the head capsule. The cuticle is weakly sclerotized and equipped with wax glands which are unique in Neuroptera. The total number of muscles is not affected by miniaturization. The phylogenetic analysis yields Coniopterygidae as sistergroup to the dilarid clade based on one larval character, the shape of the stylets. The enforced basal position of Coniopterygidae is supported by one disputable synapomorphy of the remaining Neuroptera, the presence of paraglossae in adults.

      PubDate: 2017-02-12T18:18:15Z
      DOI: 10.1016/j.asd.2016.12.004
       
  • Ontogenetic trajectory and allometry of Diplonychus rusticus (Fabricius),
           an Oriental aquatic bug (Hemiptera: Belostomatidae) from the Western Ghats
           of India
    • Authors: Dnyaneshwar Doke; Rashmi Morey; Neelesh Dahanukar; Sameer M. Padhye; Shruti V. Paripatyadar
      Abstract: Publication date: Available online 28 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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. On the basis of a CHAID (Chi-squared Automatic Interaction Detection) based regression tree, we also show that the characters – total length without head and maximum width – prove to be adequate for effective instar identification. The multivariate allometric growth pattern shows that different body parts exhibit different types of allometry. This is apparent in the allometry exhibited by forelegs and mid and hind legs, which show allometry of opposite polarities. This may be due to the different functions attributed to these body parts. Our results show that the growth pattern in D. rusticus is comparable with the New World genus Belostoma, suggesting a conserved growth pattern in the family Belostomatidae.

      PubDate: 2017-01-29T13:25:32Z
      DOI: 10.1016/j.asd.2016.12.008
       
  • Ultrastructure of chemoreceptive tarsal sensilla in an armored harvestman
           and evidence of olfaction across Laniatores (Arachnida, Opiliones)
    • Authors: Guilherme Gainett; Peter Michalik; Carsten H.G. Müller; Gonzalo Giribet; Giovanni Talarico; Rodrigo H. Willemart
      Abstract: Publication date: Available online 10 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Our data revealed that DT I and II of H. discolor are equipped with wall-pored falciform hairs (two types), wall-pored sensilla chaetica (two types) and tip-pored sensilla chaetica, while DT III and IV are mainly covered with trichomes (non-sensory) and tip-pored sensilla chaetica. The ultrastructural characteristics support an olfactory function for all wall-pored sensilla and a dual gustatory/mechanoreceptive function for tip-pored sensilla chaetica. Based on our comparative SEM survey, we show that wall-pored sensilla occur in all investigated Laniatores, demonstrating their widespread occurrence in the suborder and highlighting the importance of both legs I and II as the sensory appendages of laniatorean harvestmen. Our results provide the first morphological evidence for olfactory receptors in Laniatores and suggest that olfaction is more important for harvestmen than previously thought.
      Graphical abstract image

      PubDate: 2017-01-15T11:14:27Z
      DOI: 10.1016/j.asd.2016.12.005
       
  • Structure and postembryonic development of the intersegmental nodules in
           the non-muscular joints of the antennae in Rhodnius prolixus
    • Authors: Bibiana Ospina-Rozo; Manu Forero-Shelton; Jorge Molina
      Abstract: Publication date: Available online 6 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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 bear 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. Using Atomic Force Microscopy, we established a qualitative correlation between the topography of the surface and the rigidity of the joint between pedicel and flagellum. Our results confirmed the presence of two sub-articulations on each non-muscular joint. Also, the two intersegmental nodules have different origins: the one between the two flagellar segments (intraflagelloid) is a sclerite already present from the early nymph, while the nodule between pedicel and flagellum (prebasiflagellite) originates by gradual separation of the proximal end of the basiflagellum during postembryonic development. Various changes occur in the non-muscular joints and segments of the antenna during the life cycle of R. prolixus.
      Graphical abstract image

      PubDate: 2017-01-08T10:38:54Z
      DOI: 10.1016/j.asd.2016.12.002
       
  • The length of a short sperm: Elongation and shortening during
           spermiogenesis in Cotesia congregata (Hymenoptera, Braconidae)
    • Authors: Rustem Uzbekov; Julien Burlaud-Gaillard; Anastasiia S. Garanina; Christophe Bressac
      Abstract: Publication date: Available online 5 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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. The nucleus is 2 μm in diameter when round, 10 μm long when it becomes a long boat-hull shaped filament, and then reduces to 3.6 μm. Thus, during development the gamete reaches a total length of 15 μm before finally reducing to less than half that length. Some traits of mature sperm anatomy are similar to related species of the Braconidae family, but others seem to be specific and could be due to the shortness of the cell. This uncommon elongation and subsequent shortening of such a tiny flagellated cell constitutes a model for both nucleus and cilium development.
      Graphical abstract image

      PubDate: 2017-01-08T10:38:54Z
      DOI: 10.1016/j.asd.2016.11.011
       
  • Germ cell proliferation and cluster behavior in ovarioles of Sialis
           flavilatera (Megaloptera: Sialidae) during larval growth
    • Authors: Ralph
      Abstract: Publication date: Available online 4 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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. At least from the 10th month onwards, a Sialis ovariole anlage contains a single germ cell syncytium, whose growth is promoted by a mitotic cell population maintained in its anterior compartment. The stem-like, dividing germ cells form synchronous sub-clusters consisting of 2–16 cystocytes, which are spatially arranged in bigger rosettes that stay connected to each other via cytoplasmic tubes. Within individual rosettes, cells communicate by centrally gathering intercellular bridges. Following each round of cystocyte division and subsequent rosette formation, plasma membrane wrinkles sprout near newborn bridges, elongate, and interdigitate with the preexisting membrane tubes. In this way the membrane labyrinth emerges and grows. Germ cells leaving the proliferation zone posteriorly enter meiotic prophase. Hypotheses on the phylogenetic origin of this ovary type are discussed in the light of our results.

      PubDate: 2017-01-08T10:38:54Z
       
  • The scolopidial accessory organ in the Jerusalem cricket (Orthoptera:
           Stenopelmatidae)
    • Authors: Johannes
      Abstract: Publication date: Available online 4 January 2017
      Source:Arthropod Structure & Development
      Author(s): 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. Scolopidial sensilla occur in the posterior subgenual organ and the accessory organ in all leg pairs. The accessory organ contains 10–17 scolopidial sensilla. Both groups of sensilla are commonly spatially separated. However, in few cases neuronal fibres occurred between both organs. The two sensillum groups are considered as separate organs by the general spatial separation and innervation by different nerve branches. A functional role for mechanoreception is considered: since the accessory organ is located closely under the cuticle, sensilla may be suited to detect vibrations transferred over the leg's surface. This study extends the known taxa with an accessory organ, which occurs in several taxa of Ensifera. Comparative neuroanatomy thus suggests that the accessory organ may be conserved at least in Tettigoniidea.
      Graphical abstract image

      PubDate: 2017-01-08T10:38:54Z
       
 
 
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