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BIOLOGY (1427 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: 21)
Acta Biologica Colombiana     Open Access   (Followers: 7)
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 Neurobiologiae Experimentalis     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 9)
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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: 8)
Aging Cell     Open Access   (Followers: 10)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
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American Biology Teacher     Full-text available via subscription   (Followers: 13)
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: 6)
American Journal of Plant Sciences     Open Access   (Followers: 19)
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American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 69)
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Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
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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 Cancer Biology     Full-text available via subscription   (Followers: 1)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 38)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 19)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 24)
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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)
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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: 5)
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)
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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: 6)
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: 6)
Autophagy     Hybrid Journal   (Followers: 2)
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Avian Conservation and Ecology     Open Access   (Followers: 12)
Bacteriology Journal     Open Access   (Followers: 2)
Bacteriophage     Full-text available via subscription   (Followers: 4)
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)
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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)
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Biologia     Hybrid Journal  
Biologia on-line : Revista de divulgació de la Facultat de Biologia     Open Access  
Biological Bulletin     Partially Free   (Followers: 5)
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Biological Invasions     Hybrid Journal   (Followers: 16)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 16)
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Biology     Open Access   (Followers: 5)
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Biology Bulletin     Hybrid Journal   (Followers: 1)
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Biology Direct     Open Access   (Followers: 7)
Biology Letters     Full-text available via subscription   (Followers: 36)

        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  [3043 journals]
  • Segmentation in Tardigrada and diversification of segmental patterns in
    • 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
  • The pregenital abdomen of Enicocephalomorpha and morphological evidence
           for different modes of communication at the dawn of heteropteran evolution
    • Authors: Leonidas-Romanos Davranoglou; Petr Baňař; Christian M. Schlepütz; Beth Mortimer; Graham K. Taylor
      Abstract: Publication date: Available online 21 September 2017
      Source:Arthropod Structure & Development
      Author(s): Leonidas-Romanos Davranoglou, Petr Baňař, Christian M. Schlepütz, Beth Mortimer, Graham K. Taylor
      The internal and external anatomy of the posterior metathoracic region, pregenital abdomen, and associated nervous system of the heteropteran infraorder Enicocephalomorpha are thoroughly described, using an array of state-of-the art techniques. Based on morphology, it is hypothesised which modes of communication these insects use. This study is based primarily on an undescribed species of Cocles Bergroth, 1905 (Enicocephalidae) and another undescribed species of Lomagostus Villiers, 1958 (Aenictopecheidae), but additional representatives of the infraorder are also examined. Our results are compared with the literature on other Heteroptera. The metathoracic scent gland system of Enicocephalomorpha uses the same muscles as that of more derived Heteroptera, although the efferent system is different. The presence of a tergal plate and well-developed longitudinal musculature in the families Enicocephalidae and Aenictopecheidae, as well as a sexually dimorphic set of sclerites and membranes that allow an as yet undetermined type of motion, may indicate the presence of vibrational signaling in the infraorder, although experimental confirmation is required. Our findings raise new research questions regarding heteropteran functional morphology and communication.

      PubDate: 2017-09-23T10:28:26Z
      DOI: 10.1016/j.asd.2017.08.006
  • The scolopidial accessory organs and Nebenorgans in orthopteroid insects:
           Comparative neuroanatomy, mechanosensory function, and evolutionary origin
    • Authors: Johannes
      Abstract: Publication date: Available online 19 September 2017
      Source:Arthropod Structure & Development
      Author(s): Johannes Strauß
      Scolopidial sensilla in insects often form large sensory organs involved in proprioception or exteroception. Here the knowledge on Nebenorgans and accessory organs, two organs consisting of scolopidial sensory cells, is summarised. These organs are present in some insects which are model organisms for the physiology of mechanosensory systems (cockroaches and tettigoniids). Recent comparative studies documented the accessory organ in several taxa of Orthoptera (including tettigoniids, cave crickets, Jerusalem crickets) and the Nebenorgan in related insects (Mantophasmatodea). The accessory organ or Nebenorgan is usually a small organ of 8–15 sensilla located in the posterior leg tibia of all leg pairs. The physiological properties of the accessory organs and Nebenorgans are so far largely unknown. Taking together neuroanatomical and electrophysiological data from disparate taxa, there is considerable evidence that the accessory organ and Nebenorgan are vibrosensitive. They thus complement the larger vibrosensitive subgenual organ in the tibia. This review summarises the comparative studies of these sensory organs, in particular the arguments and criteria for the homology of the accessory organ and Nebenorgan among orthopteroid insects. Different scenarios of repeated evolutionary origins or losses of these sensory organs are discussed. Neuroanatomy allows to distinguish individual sensory organs for analysis of sensory physiology, and to infer scenarios of sensory evolution.

      PubDate: 2017-09-23T10:28:26Z
  • Advisory board/short GFA
    • Abstract: Publication date: September 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 5

      PubDate: 2017-09-23T10:28:26Z
  • The allometry of the central nervous system during the postembryonic
           development of the spider Eratigena atrica
    • Authors: Teresa Napiórkowska; Jarosław Kobak
      Abstract: Publication date: Available online 9 September 2017
      Source:Arthropod Structure & Development
      Author(s): Teresa Napiórkowska, Jarosław Kobak
      During ontogenesis, the size of a spider body, tissues and organs increases dramatically. The aim of the study was to estimate changes in the central nervous system of postembryonic stages of Eratigena atrica and compare them with the literature data on species differing in behavioural traits. Allometric analysis involved evaluation of histological slides embedded in paraffin and stained with hematoxylin and eosin. The reduced major axis regression (RMA) was applied to find allometric relationships between the volumes of the particular parts of the body. All the measured parts of the central nervous system (CNS) were negatively allometrically related to the volume of the prosoma, showing that the increment of the CNS was lower than that of the entire body. The growth of the brain was negatively allometrically related to the growth of the CNS but the increment of the subesophageal ganglion was greater than that of the CNS, exhibiting a positive allometry. Within both these structures, the increase in neuropil volume was greater than the growth of the cortex (cell body rind). Thus, in postembryonic development, the share of the subesophageal ganglion and neuropil in the total volume of the CNS increased, whereas that of the brain and cortex decreased. The mode of the CNS development in E. atrica is similar to that observed in other arthropods, including Argiope aurantia, a spider of different ecology and behaviour.

      PubDate: 2017-09-11T19:43:44Z
      DOI: 10.1016/j.asd.2017.08.005
  • Asymmetric larval head and mandibles of Hydrophilus acuminatus (Insecta:
           Coleoptera, Hydrophilidae): Fine structure and embryonic development
    • Authors: Shun'ichi Sato; Toshio Inoda; Shuhei Niitsu; Souichirou Kubota; Yuji Goto; Yukimasa Kobayashi
      Abstract: Publication date: Available online 9 September 2017
      Source:Arthropod Structure & Development
      Author(s): Shun'ichi Sato, Toshio Inoda, Shuhei Niitsu, Souichirou Kubota, Yuji Goto, Yukimasa Kobayashi
      The larvae of a water scavenger beetle, Hydrophilus acuminatus, have strongly asymmetric mandibles; the right one is long and slender, whereas the left one is short and stout. The fine structure and embryonic development of the head capsule and mandibles of this species were examined using light and scanning electron microscopy, and asymmetries in shape were detected in these structures applying an elliptic Fourier analysis. The larval mandibles are asymmetric in the following aspects: whole length, the number, structure and arrangement of retinacula (inner teeth), and size and shape of both the molar and incisor regions. The larval head is also asymmetric; the left half of the head capsule is larger than the right, and the left adductor muscle of the mandible is much thicker than the right. The origin and developmental process of asymmetric mandibles were traced in developing embryos whose developmental period is about 270 h and divided into 10 stages. Mandibular asymmetries are produced by the cumulative effects of six stepwise modifications that occur from about 36% of the total developmental time onward. The significance of these modifications was discussed with respect to the functional advantages of asymmetries and the phylogeny of members of the Hydrophilidae.

      PubDate: 2017-09-11T19:43:44Z
      DOI: 10.1016/j.asd.2017.08.003
  • From insects to robots
    • Authors: Barbara Webb
      Abstract: Publication date: Available online 1 September 2017
      Source:Arthropod Structure & Development
      Author(s): Barbara Webb

      PubDate: 2017-09-05T19:06:55Z
      DOI: 10.1016/j.asd.2017.08.002
  • A lightweight, inexpensive robotic system for insect vision
    • Authors: Chelsea Sabo; Robert Chisholm; Adam Petterson; Alex Cope
      Abstract: Publication date: Available online 1 September 2017
      Source:Arthropod Structure & Development
      Author(s): Chelsea Sabo, Robert Chisholm, Adam Petterson, Alex Cope
      Designing hardware for miniaturized robotics which mimics the capabilities of flying insects is of interest, because they share similar constraints (i.e. small size, low weight, and low energy consumption). Research in this area aims to enable robots with similarly efficient flight and cognitive abilities. Visual processing is important to flying insects' impressive flight capabilities, but currently, embodiment of insect-like visual systems is limited by the hardware systems available. Suitable hardware is either prohibitively expensive, difficult to reproduce, cannot accurately simulate insect vision characteristics, and/or is too heavy for small robotic platforms. These limitations hamper the development of platforms for embodiment which in turn hampers the progress on understanding of how biological systems fundamentally work. To address this gap, this paper proposes an inexpensive, lightweight robotic system for modelling insect vision. The system is mounted and tested on a robotic platform for mobile applications, and then the camera and insect vision models are evaluated. We analyse the potential of the system for use in embodiment of higher-level visual processes (i.e. motion detection) and also for development of navigation based on vision for robotics in general. Optic flow from sample camera data is calculated and compared to a perfect, simulated bee world showing an excellent resemblance.

      PubDate: 2017-09-05T19:06:55Z
      DOI: 10.1016/j.asd.2017.08.001
  • Vision for navigation: What can we learn from ants'
    • Authors: Paul Graham; Andrew Philippides
      Abstract: Publication date: Available online 2 August 2017
      Source:Arthropod Structure & Development
      Author(s): Paul Graham, Andrew Philippides
      The visual systems of all animals are used to provide information that can guide behaviour. In some cases insects demonstrate particularly impressive visually-guided behaviour and then we might reasonably ask how the low-resolution vision and limited neural resources of insects are tuned to particular behavioural strategies. Such questions are of interest to both biologists and to engineers seeking to emulate insect-level performance with lightweight hardware. One behaviour that insects share with many animals is the use of learnt visual information for navigation. Desert ants, in particular, are expert visual navigators. Across their foraging life, ants can learn long idiosyncratic foraging routes. What's more, these routes are learnt quickly and the visual cues that define them can be implemented for guidance independently of other social or personal information. Here we review the style of visual navigation in solitary foraging ants and consider the physiological mechanisms that underpin it. Our perspective is to consider that robust navigation comes from the optimal interaction between behavioural strategy, visual mechanisms and neural hardware. We consider each of these in turn, highlighting the value of ant-like mechanisms in biomimetic endeavours.

      PubDate: 2017-08-06T05:58:00Z
      DOI: 10.1016/j.asd.2017.07.001
  • Advisory board/short GFA
    • Abstract: Publication date: July 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 4

      PubDate: 2017-07-28T05:06:59Z
  • Jumping and the aerial behavior of aquatic mayfly larvae (Myobaetis
           ellenae, Baetidae)
    • Authors: Stephen P. Yanoviak; Robert Dudley
      Abstract: Publication date: Available online 13 July 2017
      Source:Arthropod Structure & Development
      Author(s): Stephen P. Yanoviak, Robert Dudley
      Mayfly larvae generally are aquatic, but some madicolous taxa (i.e., living in thin water films) crawl over rocks within streams and waterfalls. When startled, these larvae can break the water film, jump, and enter an aerial phase of locomotion. Because mayfly larvae have been suggested as potential exemplars for the origin of insect wings as tracheal gills, and furthermore represent the most basal extant lineage of pterygotes, we analyzed jumping behavior and free-fall trajectories for one such species of mayfly (Myobaetis ellenae, Baetidae) in Costa Rica. Jumping was commonplace in this taxon, but was undirected and was characterized by body spinning at high angular velocities. No aerodynamic role for the tracheal gills was evident. By contrast, jumping by a sympatric species of bristletail (Meinertellus sp., Archaeognatha) consistently resulted in head-first and stable body postures during aerial translation. Although capable of intermittently jumping into the air, the mayfly larvae could neither control nor target their aerial behavior. By contrast, a stable body posture during jumps in adult bristletails, together with the demonstrated capacity for directed aerial descent in arboreal representatives of this order, support ancestrally terrestrial origins for insect flight within the behavioral context of either jumping or falling from heights.

      PubDate: 2017-07-22T04:01:09Z
      DOI: 10.1016/j.asd.2017.06.005
  • Optic flow-based collision-free strategies: From insects to robots
    • Authors: Julien R. Serres; Franck Ruffier
      Abstract: Publication date: Available online 11 July 2017
      Source:Arthropod Structure & Development
      Author(s): Julien R. Serres, Franck Ruffier
      Flying insects are able to fly smartly in an unpredictable environment. It has been found that flying insects have smart neurons inside their tiny brains that are sensitive to visual motion also called optic flow. Consequently, flying insects rely mainly on visual motion during their flight maneuvers such as: takeoff or landing, terrain following, tunnel crossing, lateral and frontal obstacle avoidance, and adjusting flight speed in a cluttered environment. Optic flow can be defined as the vector field of the apparent motion of objects, surfaces, and edges in a visual scene generated by the relative motion between an observer (an eye or a camera) and the scene. Translational optic flow is particularly interesting for short-range navigation because it depends on the ratio between (i) the relative linear speed of the visual scene with respect to the observer and (ii) the distance of the observer from obstacles in the surrounding environment without any direct measurement of either speed or distance. In flying insects, roll stabilization reflex and yaw saccades attenuate any rotation at the eye level in roll and yaw respectively (i.e. to cancel any rotational optic flow) in order to ensure pure translational optic flow between two successive saccades. Our survey focuses on feedback-loops which use the translational optic flow that insects employ for collision-free navigation. Optic flow is likely, over the next decade to be one of the most important visual cues that can explain flying insects' behaviors for short-range navigation maneuvers in complex tunnels. Conversely, the biorobotic approach can therefore help to develop innovative flight control systems for flying robots with the aim of mimicking flying insects’ abilities and better understanding their flight.

      PubDate: 2017-07-22T04:01:09Z
      DOI: 10.1016/j.asd.2017.06.003
  • Structural adaptations and mechanism of reflex bleeding in the larvae of
           the myrmecophilous ladybird Diomus thoracicus
    • Authors: Olivier Roux; Amélie Vantaux; Frédéric Petitclerc; Jérôme Orivel; Alain Dejean; Johan Billen
      Abstract: Publication date: Available online 10 July 2017
      Source:Arthropod Structure & Development
      Author(s): Olivier Roux, Amélie Vantaux, Frédéric Petitclerc, Jérôme Orivel, Alain Dejean, Johan Billen
      Reflex bleeding is an effective defensive mechanism against predators. When attacked, some insects emit hemolymph, which coagulates, quickly entangling their aggressor. Bleeding occurs at weak intersegmental membranes or through dedicated organs, which can be associated or not with glandular cells. Here, we describe the behavior and morphological structures involved in reflex bleeding in the larvae of the ladybird, Diomus thoracicus, which are intranidal parasites of the ant Wasmannia auropunctata. The larvae are tolerated by the ants thanks to odor mimicry, but some rare aggressive ant behaviors were observed that trigger reflex bleeding both at a pair of thoracic tubercles and a pair of posterodorsal abdominal humps. No glandular structure was found in association with these emission points, which suggests that the material emitted was hemolymph only. A 3D reconstruction suggested that reflex bleeding seems to be controlled by muscles whose contraction increases the internal hydrostatic pressure and pushes the hemolymph into a funnel-like structure with an opening to the outside. In D. thoracicus, the morphological structures involved in reflex bleeding are among the most complex and prominent described to date.
      Graphical abstract image

      PubDate: 2017-07-22T04:01:09Z
      DOI: 10.1016/j.asd.2017.06.002
  • Show me your tenent setae and I tell you who you are – Telling the story
           of a neglected character complex with phylogenetic signals using Leiodidae
           (Coleoptera) as a case study
    • Authors: Pedro Gnaspini; Caio Antunes-Carvalho; Alfred F. Newton; Richard A.B. Leschen
      Abstract: Publication date: Available online 8 July 2017
      Source:Arthropod Structure & Development
      Author(s): Pedro Gnaspini, Caio Antunes-Carvalho, Alfred F. Newton, Richard A.B. Leschen
      The tarsal setae in 97 species of Leiodidae and eight outgroups were examined using SEM imaging and dissections. Modified adhesive setae present in males are referred to as “male tenent setae” (MTS). In most cases, dilated tarsomeres were associated with MTS, which were always present on the protarsi and sometimes the mesotarsi. MTS are reported for the first time on the mesotarsi of Leptodirini and on the metatarsi in two genera of Sogdini. Contrary to reports in the literature, the reduction in the number of the MTS bearing mesotarsomeres is considered a derived condition. Both sexes of Leptinus (Platypsyllinae) have modified setae (referred to as tenent setae in the literature), probably related to their specialised association with mammals, and a patch of MTS was recognized for the first time among those modified setae among males. Four main types of MTS are recognised: (1) a plesiomorphic discoidal type that has a shaft with a round cross-section and maintains a similar diameter throughout its length until forming the expanded discoidal terminal plate; (2) a minidiscoidal type, similar to discoidal but with a relatively small terminal plate, found in Cholevinae; (3) a conical type, present in Leiodinae (excluding Estadiini) where the shaft increases in diameter until forming the terminal plate; and (4) a spatulate type, where an even wider terminal plate has a lateral projection, derived from the conical form and synapomorphic for the leiodine tribes Pseudoliodini, Scotocryptini, and possibly Agathidiini.

      PubDate: 2017-07-11T02:21:28Z
      DOI: 10.1016/j.asd.2017.06.004
  • Perianal structures in myrmecophilous subterranean aphids (Insecta:
           Hemiptera: Aphididae) – Comparative morphology of trophobiotic organ
           with its first description in Lachninae
    • Authors: Mariusz Kanturski; Jagna Karcz; Natalia Kaszyca; Łukasz Depa
      Abstract: Publication date: Available online 6 July 2017
      Source:Arthropod Structure & Development
      Author(s): Mariusz Kanturski, Jagna Karcz, Natalia Kaszyca, Łukasz Depa
      Scanning electron microscopy (SEM) and light stereoscopic microscopy (LSM) were used for the first time to elucidate the external morphology of the so called “trophobiotic organ” on the end of abdomen of apterous viviparous females of six aphid species (Insecta: Hemiptera: Aphididae), representatives of the myrmecophilous, subterranean aphids from the subfamilies Anoeciinae (Anoecia furcata), Eriosomatinae (Forda formicaria, Geoica utricularia, Tetraneura ulmi), and Lachninae (Protrama flavescens, Trama troglodytes). We examined and compared the external morphology in the parthenogenetic generation living on roots of deciduous plants. FE-SEM images based on HMDS preparation techniques revealed great similarity of perianal structures even between not closely related groups. Rectangular, vertically positioned anal plate, extremely shortened cauda and setae around the anus seem to be common features of these aphids. However, some differences in the number and length of setae, their arrangement and inclination of anal plate may be observed. The discussion focuses on the adaptive importance of such modifications, with respect to underground life mode and myrmecophily, but with reservations concerning living in galls by representatives of Eriosomatinae, which is hypothesized to be a factor driving the development of such modifications of perianal structures in this group of aphids.
      Graphical abstract image

      PubDate: 2017-07-11T02:21:28Z
      DOI: 10.1016/j.asd.2017.06.001
  • Effects of force detecting sense organs on muscle synergies are correlated
           with their response properties
    • Authors: Sasha N. Zill; David Neff; Sumaiya Chaudhry; Annelie Exter; Josef Schmitz; Ansgar Büschges
      Abstract: Publication date: Available online 4 July 2017
      Source:Arthropod Structure & Development
      Author(s): Sasha N. Zill, David Neff, Sumaiya Chaudhry, Annelie Exter, Josef Schmitz, Ansgar Büschges
      Sense organs that monitor forces in legs can contribute to activation of muscles as synergist groups. Previous studies in cockroaches and stick insects showed that campaniform sensilla, receptors that encode forces via exoskeletal strains, enhance muscle synergies in substrate grip. However synergist activation was mediated by different groups of receptors in cockroaches (trochanteral sensilla) and stick insects (femoral sensilla). The factors underlying the differential effects are unclear as the responses of femoral campaniform sensilla have not previously been characterized. The present study characterized the structure and response properties (via extracellular recording) of the femoral sensilla in both insects. The cockroach trochantero-femoral (TrF) joint is mobile and the joint membrane acts as an elastic antagonist to the reductor muscle. Cockroach femoral campaniform sensilla show weak discharges to forces in the coxo-trochanteral (CTr) joint plane (in which forces are generated by coxal muscles) but instead encode forces directed posteriorly (TrF joint plane). In stick insects, the TrF joint is fused and femoral campaniform sensilla discharge both to forces directed posteriorly and forces in the CTr joint plane. These findings support the idea that receptors that enhance synergies encode forces in the plane of action of leg muscles used in support and propulsion.

      PubDate: 2017-07-11T02:21:28Z
      DOI: 10.1016/j.asd.2017.05.004
  • Functional morphology of comminuting feeding structures of Trichodactylus
           borellianus (Brachyura, Decapoda, Trichodactylidae), an omnivorous
           freshwater crab
    • Authors: Débora de Azevedo Carvalho; Maria Florencia Viozzi; Pablo Agustín Collins; Verónica Williner
      Abstract: Publication date: Available online 28 June 2017
      Source:Arthropod Structure & Development
      Author(s): Débora de Azevedo Carvalho, Maria Florencia Viozzi, Pablo Agustín Collins, Verónica Williner
      Crustaceans exhibit great diversity of feeding structures with morphological traits that are useful to infer the general trophic habits of species. In this study, we analyzed the functional morphology of comminuting feeding structures (mandibles, chelipeds, gastric mill) of the freshwater crab Trichodactylus borellianus directly related with the food fragmentation. The heterochely and mechanical advantage (MA) of the chelae were also studied. In both analyses, we considered the relationship between morphology and the natural diet. We expected to find a consistent relation between feeding habits and morphological traits. In general, we found simple structures armed with uniform setal systems and feeding appendages without pronounced teeth or spines. Mandibles have primarily cutting functions, helping with the food anchoring and fragmentation with mandibular palps armed with pappose setae. Chelipeds were covered with spines and simple setae. Adult males exhibited right-handedness with high MA of the major chelae. The ingested, relatively large pieces of food are finally chewed by a gastric mill equipped with sharp cusps characteristic of decapods with low ingestion of crude fiber material. The morphology of the feeding apparatus revealed that it is well adapted to an omnivorous diet, being able to cope with dietary changes.

      PubDate: 2017-07-01T20:42:33Z
      DOI: 10.1016/j.asd.2017.05.001
  • 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
    • 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
    • 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
  • 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
    • 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:
    • 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
  • 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
  • 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:
    • 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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