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Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 21)
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ACS Synthetic Biology     Full-text available via subscription   (Followers: 23)
Acta Biologica Colombiana     Open Access   (Followers: 7)
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acta ethologica     Hybrid Journal   (Followers: 4)
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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: 9)
Aging Cell     Open Access   (Followers: 11)
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)
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American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Human Biology     Hybrid Journal   (Followers: 13)
American Journal of Medical and Biological Research     Open Access   (Followers: 8)
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: 73)
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Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 16)
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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: 39)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 16)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 20)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 24)
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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: 5)
Aquatic Ecology     Hybrid Journal   (Followers: 32)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 14)
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Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
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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: 3)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 2)
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: 13)
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: 2)
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)
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Biodiversity : Research and Conservation     Open Access   (Followers: 28)
Biodiversity and Natural History     Open Access   (Followers: 6)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     Open Access   (Followers: 1)
Biodiversity Information Science and Standards     Open Access  
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
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Biologia     Hybrid Journal  
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Biological Invasions     Hybrid Journal   (Followers: 17)
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Biology and Philosophy     Hybrid Journal   (Followers: 17)
Biology Bulletin     Hybrid Journal   (Followers: 1)
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        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  [3118 journals]
  • Drinking with a very long proboscis: Functional morphology of orchid bee
           mouthparts (Euglossini, Apidae, Hymenoptera)
    • Authors: Jellena V. Düster; Maria H. Gruber; Florian Karolyi; John D. Plant; Harald W. Krenn
      Abstract: Publication date: Available online 29 December 2017
      Source:Arthropod Structure & Development
      Author(s): Jellena V. Düster, Maria H. Gruber, Florian Karolyi, John D. Plant, Harald W. Krenn
      Neotropical orchid bees (Euglossini) possess the longest proboscides among bees. In this study, we compared the feeding behavior and functional morphology of mouthparts in two similarly large-sized species of Euglossa that differ greatly in proboscis length. Feeding observations and experiments conducted under semi-natural conditions were combined with micro-morphological examination using LM, SEM and micro CT techniques. The morphometric comparison showed that only the components of the mouthparts that form the food tube differ in length, while the proximal components, which are responsible for proboscis movements, are similar in size. This study represents the first documentation of lapping behaviour in Euglossini. We demonstrate that Euglossa bees use a lapping-sucking mode of feeding to take up small amounts of fluid, and a purely suctorial technique for larger fluid quantities. The mouthpart movements are largely similar to that in other long-tongued bees, except that the postmentum in Euglossa can be extended, greatly enhancing the protraction of the glossa. This results in a maximal functional length that is about 50% longer than the length of the food canal composing parts of the proboscis. The nectar uptake and the sensory equipment of the proboscis are discussed in context to flower probing.

      PubDate: 2018-01-05T07:18:52Z
      DOI: 10.1016/j.asd.2017.12.004
  • Comparison of sensory structures on the antenna of different species of
           Philopotamidae (Insecta: Trichoptera)
    • Authors: Stanislav I. Melnitsky; Vladimir D. Ivanov; Mikhail Yu Valuyskiy; Lydia V. Zueva; Marianna I. Zhukovskaya
      Abstract: Publication date: Available online 28 December 2017
      Source:Arthropod Structure & Development
      Author(s): Stanislav I. Melnitsky, Vladimir D. Ivanov, Mikhail Yu Valuyskiy, Lydia V. Zueva, Marianna I. Zhukovskaya
      Structure and distribution of sensilla were studied in sixteen species of the caddisfly family Philopotamidae. Their antennae bear numerous curved trichoid and pseudoplacoid sensilla and fewer coronal, styloconic and chaetoid sensilla on the flagellar segments. The most numerous pseudoplacoid sensilla have non-specific localization. The curved trichoid sensilla form clusters ventrally on each antennal segment. Sensilla belonging to coronal, styloconic and chaetoid types have specific positions. Long grooved trichoid sensilla are located nonspecifically in all the studied species. The average number of sensilla per segment decreases from the proximal to distal part of the flagellum. Scapus and pedicellum are devoid of most types of sensilla, however, they bear the Böhm bristles and long trichoid sensilla. A positive correlation between antenna dimensions and its cuticular structures is found.

      PubDate: 2018-01-05T07:18:52Z
      DOI: 10.1016/j.asd.2017.12.003
  • The eversible tentacle organs of Polyommatus caterpillars (Lepidoptera,
           Lycaenidae): Morphology, fine structure, sensory supply and functional
    • Authors: W. Gnatzy; M. Jatho; T. Kleinteich; S.N. Gorb; R. Hustert
      Pages: 788 - 804
      Abstract: Publication date: November 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 6
      Author(s): W. Gnatzy, M. Jatho, T. Kleinteich, S.N. Gorb, R. Hustert
      In their late (3rd and 4th) larval stages, caterpillars of the myrmecophilous lycaenid (Lepidoptera) species Polyommatus coridon and Polyommatus icarus, possess on their 8th abdominal segment two eversible so called tentacle organs (TOs). Previous histological and behavioural results have proposed that the TOs may release a volatile substance that elicits “excited runs” in attendant ants. In our study we investigated for the first time the temporal in- and eversion pattern of TOs. Using nerve tracing, Micro-CT, light- and electron microscopy techniques we studied (i) the histology of the 8th abdominal segment, (ii) the fine structure of the cuticular and cellular apparatus of the TOs, (iii) the attachment sites of the retractor muscle of each TO and (iv) the fine structure of the long slender tentacle hairs which are exposed to the outside, when the TOs are everted and fold back into the TO-sac during inversion. Our data show that the tentacle hairs are typical insect mechanoreceptors, each innervated by a small bipolar sensory cell with a tubular body in the tip of the outer dendritic segment. The latter is enclosed by a cuticular sheath previously called the “internal cuticular duct” and misinterpreted in earlier studies as the space, where the tentacle hairs actively secrete fluids. However, we found no glandular structures nearby or in the wall of the TO-sac. Also we did not reveal any conspicuous signs of secretory activity in one of the enveloping cells belonging to a tentacle hair. Although highly unusual features for an insect mechanoreceptor are: (a) the hair-shaft lumen of tentacle hairs contains flocculent material as well small vesicles and (b) the thin cuticular wall of the hair-shaft and its spines possess few tiny pores. Our data do not support the assumption of previous studies that volatile substances are released via the tentacle organs during their interactions with ants which in turn are supposed to cause excited runs in ants.

      PubDate: 2017-12-01T11:12:23Z
      DOI: 10.1016/j.asd.2017.10.003
  • Egg-laying behavior and morphological and chemical characterization of egg
           surface and egg attachment glue of the digger wasp Ampulex compressa
           (Hymenoptera, Ampulicidae)
    • Authors: Werner Gnatzy; Walter Volknandt; Anja Dzwoneck
      Abstract: Publication date: Available online 21 December 2017
      Source:Arthropod Structure & Development
      Author(s): Werner Gnatzy, Walter Volknandt, Anja Dzwoneck
      For providing their offspring females of the digger wasp species Ampulex compressa hunt cockroaches, paralyze them and attach as a rule one egg to the coxa of one of the mid legs of their prey. We observed the egg-laying behavior and examined with light- and scanning microscopy (i) nearly mature eggs from ovaries of freshly dissected females and (ii) eggs immediately after their deposition on the coxae of their prey. The length of the white bean-shaped eggs varied between 2.2 and 3.0 mm, their diameter between 0.66 and 0.72 mm, and their weight between 345 and 832 μg. The surface of fresh, untreated eggs shows even at higher magnifications (>20.000×) a smooth appearance. However, after conventional fixation, dehydration with ethyl-alcohol and critical-point drying the egg-surface exhibited a little bit texture. The eggs are at two-third of their underside glued to the coxa of the prey. With the naked eye the glue appears as a compact mass. The eggs may be mechanically removed from the substrate (their attachment site); however, in doing so the viscous attachment glue appears in a more fibrous consistence. The polypeptide composition washed off the egg surface and the glue revealed no similarities, whereas the molecular mass of two polypeptides were similar between glue and the Dufour's gland contents.

      PubDate: 2017-12-24T05:17:56Z
      DOI: 10.1016/j.asd.2017.11.010
  • Paradorippe granulata – A crab with external fertilization and a novel
           type of sperm storage organ challenges prevalent ideas on the evolution of
           reproduction in Eubrachyura (Crustacea: Brachyura: Dorippidae)
    • Authors: Juliane Vehof; Gerhard Scholtz; Carola Becker
      Abstract: Publication date: Available online 19 December 2017
      Source:Arthropod Structure & Development
      Author(s): Juliane Vehof, Gerhard Scholtz, Carola Becker
      Two fundamentally different sperm storage organs occur in Brachyura. The probably paraphyletic podotremes show intersegmental spermathecae, which are distant from oviducts and coxal gonopores. Hence, fertilization is external. In contrast to this, the seminal receptacles of Eubrachyura are directly connected with the ovaries. Thus, at least initial fertilization is internal. This pattern has been interpreted as an apomorphy of Eubrachyura. To test this hypothesis, we studied the morphology of the reproductive organs of Paradorippe granulata, a representative of the putatively early diverging eubrachyuran lineage Dorippoidea. Applying histology, 3D-reconstructions and micro-computed-tomography we revealed a novel type of sperm storage organ. Female P . granulata lack the characteristic eubrachyuran seminal receptacle. Instead sperm is stored in four cuticle-lined bursae, two on each side of the paired oviducts. The elaborate bulbous male gonopod with several terminal processes is adapted to transferring sperm into the female twin bursae. Since oviducts and twin bursae are not directly connected, spermatozoa and oocytes mix when gametes pass through the sternal vulva. Thus, fertilization in P . granulata is external. Our finding of a eubrachyuran crab that lacks seminal receptacles and exhibits external fertilization calls prevailing concepts on the evolution of sperm storage in Eubrachyura into question.
      Graphical abstract image

      PubDate: 2017-12-24T05:17:56Z
      DOI: 10.1016/j.asd.2017.12.002
  • The morphology of mouthparts, wings and genitalia of Paleozoic insect
           families Protohymenidae and Scytohymenidae reveals new details and
           supposed function
    • Authors: Martina Pecharová; Jakub Prokop
      Abstract: Publication date: Available online 18 December 2017
      Source:Arthropod Structure & Development
      Author(s): Martina Pecharová, Jakub Prokop
      Megasecoptera is an extinct group of insects with specialized rostrum-like mouthparts, which is a synapomorphy shared with all members of the Late Paleozoic Palaeodictyopterida, and markedly slender wings that are unable to flex backwards. Here we describe the close up morphology of Protohymenidae and Scytohymenidae and uncover new aspects of the endoskeleton (tentorium) of the head, structure of the mouthparts with discernible proximal part of stylets controlled by muscles, surface of compound eyes that consist of a hexagonal pattern of large facets, structure and microstructures on the wings and reconstruct male and female external genitalia using ESEM and light stereomicroscopy. Furthermore, we describe Protohymen novokshonovi sp. n. based on an exceptionally well preserved fossil from the early Permian at Tshekarda in Russia, which shows crucial details, and the earliest species of Protohymenidae, Carbohymen testai gen. et sp. n. from a late Carboniferous siderite nodule at Mazon Creek in Illinois, USA. Our comparative study confirmed a set of structural and microstructural details on their wings, such as the composite anterior wing margin, development of an apical cell and the previously unknown external genitalia. Based on the results and comparison of homologous structures known primarily for extant relatives, such as mayflies and dragonflies, we outline for the first time the function of the mouthparts, in particular, the stylets, structure of the tentorium, vision provided by large hexagonal ommatidia and male copulatory structures bearing curved claspers for holding a female during copulation and penial lobes with seminal grooves.

      PubDate: 2017-12-24T05:17:56Z
      DOI: 10.1016/j.asd.2017.11.006
  • “Open access” growth histories in millipedes (Diplopoda)
    • Authors: Henrik Enghoff; Laura Mark Jensen; Elena V. Mikhaljova
      Abstract: Publication date: Available online 16 December 2017
      Source:Arthropod Structure & Development
      Author(s): Henrik Enghoff, Laura Mark Jensen, Elena V. Mikhaljova
      A unique pattern of missing defence glands on certain body rings is described for two species of the millipede family Mongoliulidae, order Julida: Ussuriiulus pilifer Golovatch, 1980, and Koiulus interruptus Enghoff et al., 2017. Based on the patterns of missing glands observed in recently collected samples of the two species, numbers of podous and apodous body rings in successive stadia of the postembryonic development can be inferred for each individual millipede, which in turn allows the reconstruction of pathways of anamorphosis in these species. The inferred numbers of body rings in developmental stadia are compared with actual numbers observed on additional samples, including the type series, of U. pilifer. The pattern of missing glands in the two mongoliulid species is compared with the pattern of missing glands typical of the entire millipede order Polydesmida.
      Graphical abstract image

      PubDate: 2017-12-24T05:17:56Z
      DOI: 10.1016/j.asd.2017.11.009
  • The gnathobasic spine microstructure of recent and Silurian chelicerates
           and the Cambrian artiopodan Sidneyia: Functional and evolutionary
    • Authors: Russell D.C. Bicknell; John R. Paterson; Jean-Bernard Caron; Christian B. Skovsted
      Abstract: Publication date: Available online 15 December 2017
      Source:Arthropod Structure & Development
      Author(s): Russell D.C. Bicknell, John R. Paterson, Jean-Bernard Caron, Christian B. Skovsted
      Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyia inexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has a similar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemus and S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively. This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basal artiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.

      PubDate: 2017-12-24T05:17:56Z
      DOI: 10.1016/j.asd.2017.12.001
  • The antennae of damselfly larvae
    • Authors: Silvana Piersanti; Manuela Rebora
      Abstract: Publication date: Available online 12 December 2017
      Source:Arthropod Structure & Development
      Author(s): Silvana Piersanti, Manuela Rebora
      The larval antennal sensilla of two Zygoptera species, Calopteryx haemorroidalis (Calopterygidae) and Ischnura elegans (Coenagrionidae) are investigated with SEM and TEM. These two species have different antennae (geniculate, setaceous) and live in different environments (lotic, lentic waters). Notwithstanding this, similarities in the kind and distribution of sensilla are outlined: in both species the majority of sensilla types is located on the apical portion of the antenna, namely a composed coeloconic sensillum (possible chemoreceptor), two other coeloconic sensilla (possible thermo-hygroreceptors) and an apical seta (direct contact mechanoreceptor). Other mechanoreceptors, such as filiform hairs sensitive to movements of the surrounding medium or bristles positioned to sense the movements of the flagellar segments, are present on the antenna. Similarities in the antennal sensilla types and distribution are observed also with other dragonfly species, such as Onychogomphus forcipatus and Libellula depressa. A peculiar structure with an internal organization similar to that of a gland is observed in the apical antenna of C. haemorroidalis and I. elegans and it is present also in O. forcipatus and L. depressa. The possible function of this structure is at the moment unknown but deserves further investigations owing to its widespread presence in Odonata larvae.
      Graphical abstract image

      PubDate: 2017-12-13T03:17:54Z
      DOI: 10.1016/j.asd.2017.11.008
  • A century and a half of research on the evolution of insect flight
    • Authors: David E. Alexander
      Abstract: Publication date: Available online 6 December 2017
      Source:Arthropod Structure & Development
      Author(s): David E. Alexander
      The gill and paranotal lobe theories of insect wing evolution were both proposed in the 1870s. For most of the 20th century, the paranotal lobe theory was more widely accepted, probably due to the fundamentally terrestrial tracheal respiratory system; in the 1970s, some researchers advocated for an elaborated gill (“pleural appendage”) theory. Lacking transition fossils, neither theory could be definitively rejected. Winged insects are abundant in the fossil record from the mid-Carboniferous, but insect fossils are vanishingly rare earlier, and all earlier fossils are from primitively wingless insects. The enigmatic, isolated mandibles of Rhyniognatha (early Devonian) hint that pterygotes may have been present much earlier, but the question remains open. In the late 20th century, researchers used models to study the interaction of body and protowing size on solar warming and gliding abilities, and stability and glide effectiveness of many tiny adjustable winglets versus a single, large pair of immobile winglets. Living stoneflies inspired the surface-skimming theory, which provides a mechanism to bridge between aquatic gills and flapping wings. The serendipitously discovered phenomenon of directed aerial descent suggests a likely route to the early origin of insect flight. It provides a biomechanically feasible sequence from guided falls to fully-powered flight.
      Graphical abstract image

      PubDate: 2017-12-12T03:12:02Z
      DOI: 10.1016/j.asd.2017.11.007
  • Head shape variation in cerambycid saproxylic beetles as a function of
           host plant selection
    • Authors: Sandra M. Ospina-Garcés; José Alfredo Hernández-Cardenas; Víctor H. Toledo-Hernández; Angélica M. Corona-López; Alejandro Flores-Palacios
      Abstract: Publication date: Available online 1 December 2017
      Source:Arthropod Structure & Development
      Author(s): Sandra M. Ospina-Garcés, José Alfredo Hernández-Cardenas, Víctor H. Toledo-Hernández, Angélica M. Corona-López, Alejandro Flores-Palacios
      Saproxylic insects depend on deadwood for larval development, and a certain degree of specialization may be involved in their choice of host plants and/or wood in a particular stage of degradation. The plant species chosen for oviposition in turn act as an environmental pressure on the head morphology of larvae and it is expected that head shape plasticity varies directly with the number of woody plant species used for larval development in each insect species. We analyzed head shape variation in saproxylic beetles with respect to host plant species, maximum time of larval emergence and season of the year when insects colonized branches. Generalist species in the use of host plants showed significant variation in head shape and size. Time of emergence and season did not appear to affect head shape, although season was a determinant factor of abundance and possibly head size variation.

      PubDate: 2017-12-12T03:12:02Z
      DOI: 10.1016/j.asd.2017.11.005
  • Corrigendum to “Timing of autophagy and apoptosis during posterior silk
           gland degeneration in Bombyx mori” [Arthropod Struct. Dev. 46 (4) (2017)
    • Authors: Aurora Montali; Davide Romanelli; Silvia Cappellozza; Annalisa Grimaldi; Magda de Eguileor; Gianluca Tettamanti
      Abstract: Publication date: Available online 28 November 2017
      Source:Arthropod Structure & Development
      Author(s): Aurora Montali, Davide Romanelli, Silvia Cappellozza, Annalisa Grimaldi, Magda de Eguileor, Gianluca Tettamanti

      PubDate: 2017-12-01T11:12:23Z
      DOI: 10.1016/j.asd.2017.11.004
  • Egg structure and outline of embryonic development of the basal mantodean,
           Metallyticus splendidus Westwood, 1835 (Insecta, Mantodea, Metallyticidae)
    • Authors: Makiko Fukui; Mari Fujita; Shigekazu Tomizuka; Yuta Mashimo; Shota Shimizu; Chow-Yang Lee; Yasunori Murakami; Ryuichiro Machida
      Abstract: Publication date: Available online 26 November 2017
      Source:Arthropod Structure & Development
      Author(s): Makiko Fukui, Mari Fujita, Shigekazu Tomizuka, Yuta Mashimo, Shota Shimizu, Chow-Yang Lee, Yasunori Murakami, Ryuichiro Machida
      The egg structure and outline of the embryonic development of Metallyticus splendidus of one of the basal Mantodea representatives, Metallyticidae, were described in the present study. The results obtained were compared with those from the previous studies, to reconstruct and discuss the groundplan of Mantodea and Dictyoptera. In M. splendidus, the egg is spheroidal, it has a convex ventral side at the center in which numerous micropyles are grouped, and it possesses a conspicuous hatching line in its anterior half. These are the groundplan features of mantodean eggs and the “grouped micropyles in the ventral side of the egg” are regarded as an apomorphic groundplan feature of Dictyoptera. A small circular embryo is formed by a simple concentration of blastoderm cells, which then undergoes embryogenesis of the typical short germ band type. Blastokinesis is of the “non-reversion type” and the embryo keeps its original superficial position and original orientation throughout embryonic development. During the middle stages of development, the embryo undergoes rotation around the egg's anteroposterior axis. These features are a part of the groundplan of Mantodea. It is uncertain whether sharing of the “non-reversion type” of blastokinesis by Mantodea and blaberoidean Blattodea can be regarded as homology or homoplasy.

      PubDate: 2017-12-01T11:12:23Z
      DOI: 10.1016/j.asd.2017.11.001
  • Larval development of the symbiotic pea crab Pinnaxodes chilensis
           (H. Milne Edwards, 1837) (Decapoda, Brachyura, Pinnotheridae) reared in
    • Authors: M.E. Gonzalez-Canales; E. Marco-Herrero; M. Andreu-Cazenave; J.I. González-Gordillo
      Abstract: Publication date: Available online 20 November 2017
      Source:Arthropod Structure & Development
      Author(s): M.E. Gonzalez-Canales, E. Marco-Herrero, M. Andreu-Cazenave, J.I. González-Gordillo
      The complete larval development of Pinnaxodes chilensis (including four zoeal stages and a megalopa stage) is described and illustrated in detail for the first time. The descriptions are based on laboratory-reared larvae obtained from ovigerous females found inside specimens of the sea urchin Loxechinus albus collected in the coast of Valparaíso, Chile. In order to allow the correct differentiation of specimens from plankton samples, the larval stages of P. chilensis are compared with those from other Pinnotheridae species, whose larval development is known for the Chilean continental waters (Calyptraeotheres politus). The morphological characters described for P. chilensis larvae, as well as the comparison with the remaining larval development descriptions available for the genus Pinnaxodes, are used to discuss the heterogeneity within this genus.

      PubDate: 2017-12-01T11:12:23Z
      DOI: 10.1016/j.asd.2017.11.003
  • Advisory board/short GFA
    • Abstract: Publication date: November 2017
      Source:Arthropod Structure & Development, Volume 46, Issue 6

      PubDate: 2017-12-01T11:12:23Z
  • Yeast-like microorganisms in the scale insect Kermes quercus (Insecta,
           Hemiptera, Coccomorpha: Kermesidae). Newly acquired symbionts'
    • Authors: Elżbieta Podsiadło; Katarzyna Michalik; Anna Michalik; Teresa Szklarzewicz
      Abstract: Publication date: Available online 14 November 2017
      Source:Arthropod Structure & Development
      Author(s): Elżbieta Podsiadło, Katarzyna Michalik, Anna Michalik, Teresa Szklarzewicz
      Scale insects, like other plant sap-consumers, are host to symbiotic microorganisms which provide them with the substances missing from their diet. In contrast to most scale insects, Kermes quercus (Linnaeus) was regarded as asymbiotic. Our histological and ultrastructural observations show that in the body of the feeding stages of K. quercus collected in two locations (Warsaw and Cracow), numerous yeast-like microorganisms occur. These microorganisms were localized in the cytoplasm of fat body cells. The yeast-like microorganisms were observed neither in other organs of the host insect nor in the eggs. These microorganisms did not cause any damage to the structure of the ovaries and the course of oogenesis of the host insect. The females infected by them produced about 1300 larvae. The lack of these microorganisms in the cytoplasm of eggs indicates that they are not transmitted transovarially from mother to offspring. Molecular analyses indicated that the microorganisms which reside in the body of K. quercus are closely related to the entomopathogenic fungi Cordyceps and Ophiocordyceps, which belong to the Sordariomycetes class within the Ascomycota. The role of yeast-like microorganisms to their host insects remains unknown; however, it has been suggested that they may represent newly acquired symbionts.
      Graphical abstract image

      PubDate: 2017-11-18T12:51:52Z
      DOI: 10.1016/j.asd.2017.11.002
  • Evidence of a procentriole during spermiogenesis in the coccinellid insect
           Adalia decempunctata (L): An ultrastructural study
    • Authors: Romano Dallai; David Mercati; José Lino-Neto; Glenda Dias; Pietro Lupetti
      Abstract: Publication date: Available online 6 November 2017
      Source:Arthropod Structure & Development
      Author(s): Romano Dallai, David Mercati, José Lino-Neto, Glenda Dias, Pietro Lupetti
      We studied spermatogenesis and spermiogenesis in A dalia decempunctata (L), a beetle of the Coccinellidae family. The spermatocyte exhibits two centrioles which elongate to form a pair of primary cilia. A novel structure, appearing in cross sections as a dense droplet, is observed near the long centriole during spermiogenesis, and is soon accompanied by a procentriole (PCL). PCL structure consists of singlet microtubules, a central tubule and an incomplete cartwheel. The PCL persists until the end of spermiogenesis, when it vanishes together with the dense droplet. The sperm has an exceptionally long basal body and the nucleus is disposed parallel to the flagellar components, a peculiar trait shared by other species of the coccinellid group. The presence of a procentriole suggested by the use of antibodies is discussed.

      PubDate: 2017-11-11T12:05:56Z
      DOI: 10.1016/j.asd.2017.10.004
  • Scorpions pectines – Idiosyncratic chemo- and mechanosensory organs
    • Authors: Harald Wolf
      Abstract: Publication date: Available online 27 October 2017
      Source:Arthropod Structure & Development
      Author(s): Harald Wolf
      Scorpions possess specialised chemosensory appendages, the pectines. These comb-shaped limbs are located ventrally behind the walking legs. Like the antennae of mandibulate arthropods, they also serve a mechanosensory function. However, more than 90% of the sometimes well above 100,000 sensory neurons projecting from a pectine to the central nervous system are chemosensory. There are two primary projection neuropils. The posterior one, immediately adjacent to the pectine nerve entrance, has an intriguing substructure reminiscent of the olfactory glomeruli observed in the primary chemosensory neuropils of many arthropods and indeed of most bilaterian animals. There are further similarities, particularly to the antennal lobes of mandibulate arthropods, including dense innervation by a relatively small number of putative serotonergic interneurons and the presence of GABA immunoreactivity, indicative of inhibitory interactions. Scorpion idiosyncrasies include the flattened shape and broad size range of the glomerulus-like neuropil compartments. Further, these compartments are often not clearly delimited and form layers in the neuropil that are arranged like onion peels. In summary, the pectine appendages of scorpions and their central nervous projections appear as promising study subjects, particularly regarding comparative examination of chemosensory representation and processing strategies. The possibility of combined, rather than discrete, representations of chemo- and mechanosensory inputs should merit further study.

      PubDate: 2017-11-05T11:07:05Z
      DOI: 10.1016/j.asd.2017.10.002
  • Morpho-functional variety of the coxal glands in cheyletoid mites
           (Prostigmata). II. Cheyletidae
    • Authors: S.A. Filimonova
      Abstract: Publication date: Available online 23 October 2017
      Source:Arthropod Structure & Development
      Author(s): S.A. Filimonova
      Trombidiform mites are characterized by the presence of several paired glands in the anterior body portion united by a common conducting duct (podocephalic canal). Apart from the acinous (salivary) glands the podocephalic system includes a pair of tubular coxal glands (CGs) responsible for osmoregulation. The aim of the present study was to figure out how functional changes of acinous glands reflect on the corresponding CG. For this purpose, the anatomy and fine structure of the CG were analyzed in two mite species, Bakericheyla chanayi and Ornithocheyletia sp. (Cheyletidae), which have a different composition of their single acinous gland. The results showed that in both species the CG lacks a filtering saccule. It is composed of the proximal and distal tubes and leads into a cuticle-lined excretory duct. Both tubes demonstrate a similar species-specific fine structure. They are characterized by an extensive system of apical membrane invaginations (internal canals) associated with numerous large mitochondria. Local areas of modified internal canals were regularly observed in both species. They contain structures resembling those constituting filtering slit diaphragms of other animals. In O. sp., CG cells in addition demonstrate features characteristic of protein-like secretion. Apparently this correlates with the loss of true salivary glands in this species, as its acinous gland was previously assumed as silk producing. Contrary to this, the CG of B. chanayi shows no kind of granulation, which coincides with the presence of a salivary portion in its complex acinous gland. The microtubule-rich intercalary cells at the base of the excretory duct were associated with special muscles presumably regulating the dilation of the duct lumen. These cells might represent a basic feature common to different types of podocephalic glands.

      PubDate: 2017-11-05T11:07:05Z
      DOI: 10.1016/j.asd.2017.10.001
  • 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
  • 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
  • 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
  • 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
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