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Arthropod Structure & Development

Hendrikje Hein, Sandra Smyth, Ximena Altamirano, Gerhard Scholtz
Naupliar development in copepods includes the generation of usually five pairs of post-mandibular segments. Since copepod nauplii show no outer body articulation, the only indication of larval segmentation is the expression of limb buds. Yet, in copepods the timing and sequence of limb bud expression in larval development varies to a large degree. In harpacticoid nauplii for instance, the 1st maxillae are formed at an early naupliar stage. By contrast, the four remaining pairs of limb buds frequently appear simultaneously with the last naupliar stage...
April 8, 2019: Arthropod Structure & Development
Maurizio Muzzi, Andrea Di Giulio
Bombardier beetles are famous for their unique ability to explosively discharge hot quinones from their pygidial glands when threatened. Here we provide the first detailed description of the ultrastructure of the defensive gland system of the genus Paussus, the most speciose genus in the ground beetle subfamily Paussinae. Paussine beetles are commonly known as "flanged bombardier beetles" due to the presence of a flange on their elytra that assists in directing their defensive chemicals toward the front of their bodies...
March 17, 2019: Arthropod Structure & Development
Xin Tong, Bao-Zhen Hua
Males of Panorpodidae possess a special sperm pump, through which they directly transfer seminal fluid to the female spermatheca. However, the sperm pump has not been studied in Panorpodes to date. Here, the structure of the sperm pump and the internal coupling of genitalia were investigated in the short-faced scorpionfly Panorpodes kuandianensis (Zhong, Zhang, and Hua, 2011) using light and scanning electron microscopy. The sperm pump mainly consists of a piston, a pumping chamber, the anterior region of the aedeagal complex, the posterior region of the ejaculatory sac, and associated muscles...
March 16, 2019: Arthropod Structure & Development
Adrian Richter, Roberto A Keller, Félix Baumgarten Rosumek, Evan P Economo, Francisco Hita Garcia, Rolf Georg Beutel
Despite the ecological significance of ants and the intensive research attention they have received, thorough treatments of ant anatomy and functional morphology are still scarce. In this study we document the head morphology of workers of the myrmicine Wasmannia affinis with optical microscopy, μ-computed tomography, scanning electron microscopy, and 3D reconstruction, providing the first complete anatomical treatment of an ant head with a broad array of modern techniques. We discuss the potential of the applied methods to generate detailed and well-documented morphological data sets with increased efficiency...
February 6, 2019: Arthropod Structure & Development
Susanne Randolf, Dominique Zimmermann
We present the first morphological study of the internal head structures of adults of the coniopterygid genus Aleuropteryx, which belong to the smallest known lacewings. The head is ventrally closed with a gula, which is unique in adult Neuroptera and otherwise developed in Megaloptera, the sister group of Neuroptera. The dorsal tentorial arms are directed posteriorly and fused, forming an arch that fulfills functions otherwise taken by the tentorial bridge. A newly found maxillary gland is present in both sexes...
February 4, 2019: Arthropod Structure & Development
Olivier Montreuil, Christophe Candet, Alexandre Bonaccorso, Caroline R Szczepanski, François Orange, René-Paul Godeau, Frédéric Guittard, Thierry Darmanin, Guilhem Godeau
In the animal kingdom, macroscopic variations in size, color, and even hairiness are frequently observed between male and female, making the sex of various species easy to discern. In the case of insects, similar variances also exist. While direct observation is a quick and efficient way to differentiate between sexes, there are also variations which are unseen to the naked eye and occur on a micro- or nanoscopic scale. Sometimes, these micro/nanoscopic variations can lead to significant variations in surface properties as a function of sex...
February 2, 2019: Arthropod Structure & Development
Nikola Vesović, Ana Ivanović, Srećko Ćurčić
We investigated morphometric variation in size and shape of the head, pronotum, and abdomen between the taxa and sexes of two ground beetles, Carabus coriaceus cerisyi Dejean, 1826 and C. kollari praecellens Palliardi, 1825. These two taxa differ in overall size, and both of them are characterized by significant sexual size dimorphism. In many taxa, allometry, the relationship between changes in shape and changes in size, can be a major component of intra- and interspecific variation in body shape. In the present study, we applied landmark-based geometric morphometrics to explore allometric and non-allometric components of shape variation between the taxa and more importantly between sexes within the taxa...
January 30, 2019: Arthropod Structure & Development
Adam M Rork, István Mikó, Tanya Renner
The pygidial gland system is a key innovation in adephagan beetles, producing, storing, and spraying defensive chemical compounds. As the source of defensive chemical production and storage, the pygidial gland system experiences severe chemical stress which challenges the integrity of the entire gland system. Here, we utilize autofluorescence-based confocal laser scanning microscopy to examine the morphology of pygidial gland secretory lobes and collecting ductules in a common Pennsylvanian harpaline species, Harpalus pensylvanicus...
January 28, 2019: Arthropod Structure & Development
Margarita I Yavorskaya, Rolf G Beutel, Sergey E Farisenkov, Alexey A Polilov
Pterothoracic structures of the minute ptiliid Nephanes titan were examined and described in detail. Effects of miniaturization and the phylogenetic and functional background are discussed. Apomorphies shared with Hydraenidae are the large metascutal shield, the fringe of setae along the posterior edge of the wings, and the fusion of the mesoventrite with the mesanepisternum. Autapomorphies of Ptiliidae are the highly modified feather-like wings, the strongly elongated alacristae, the loss of the mesotrochantin, the enlarged metathoracic pleural wing joint, and the simplification of the direct flight musculature...
January 10, 2019: Arthropod Structure & Development
Alexey A Polilov, Natalia I Reshetnikova, Pyotr N Petrov, Sergey E Farisenkov
The wings of Ptiliidae, the coleopteran family containing the smallest free-living insects, are analyzed in detail for the first time. A reconstruction of the evolutionary sequence of changes associated with miniaturization is proposed. The wings of several species are described using light microscopy and scanning electron microscopy. The morphology and scaling are analyzed in comparison with larger representatives of related groups. The wings of all studied ptiliids show some degree of ptiloptery (feather-like shape, typical for extremely small insects)...
January 7, 2019: Arthropod Structure & Development
Anastasia Alexeevna Makarova, Victor Benne Meyer-Rochow, Alexey Alexeevich Polilov
The coleopteran family Ptiliidae (featherwing beetles) includes some of the smallest insects known with most of the representatives of this family measuring less than 1 mm in body length. A small body size largely determines the morphology, physiology, and biology of an organism and affects the organization of complex sense organs. Information on the organization of the compound eyes of Ptiliidae is scarce. Using scanning electron microscopy we analyzed the eyes of representatives of all subfamilies and tribes and provide a detailed description of the eye ultrastructure of four species (Nephanes titan, Porophila mystacea, Nanosella sp...
January 6, 2019: Arthropod Structure & Development
Alexey A Polilov, Rolf G Beutel
No abstract text is available yet for this article.
January 2019: Arthropod Structure & Development
Barbara Beltz, Gerhard Scholtz, Alexander Steinbrecht
No abstract text is available yet for this article.
January 2019: Arthropod Structure & Development
Stefan Fischer, Zhiyuan Lu, Ian A Meinertzhagen
Existing information on insect compound eyes is mainly limited to two-dimensional information derived from histological or ultrathin sections. These allow a basic description of eye morphology, but are limited in z-axis resolution because of the section thickness or intervals between sections, so that accurate volumetric information cannot be generated. Here we use serial-sectioning transmission electron microscopy to present a 3-D reconstruction at ultrastructural level of a complete ommatidium of a miniaturized insect compound eye...
December 31, 2018: Arthropod Structure & Development
Diego Castejón, Guiomar Rotllant, Javier Alba-Tercedor, Maria Font-I-Furnols, Enric Ribes, Mercè Durfort, Guillermo Guerao
We studied the anatomy and cytology of the midgut gland (MGl) of the common spider crab Maja brachydactyla Balss 1922 at several life stages (zoea, megalopa, first juvenile, and adult) using dissection, histology, electron microscopy, computed tomography, and micro-computed tomography (micro-CT). In newly hatched larvae, 14 blind-end tubules formed the MGl. The length of the tubules increases during the larval development. In the late megalopa, the number of tubules also increases. In adults, 35,000 to 60,000 blind-end tubules comprise the MGl...
December 14, 2018: Arthropod Structure & Development
Magdalena Rost-Roszkowska, Kamil Janelt, Izabela Poprawa
Thulinius ruffoi is a small freshwater tardigrade that lives in both non-polluted and polluted freshwater environments. As a result of tardigradan body miniaturization, the digestive system is reduced and simplified. It consists of a short fore- and hindgut, and the midgut in the shape of a short tube is lined with a simple epithelium. The midgut epithelium is formed by the digestive cells and two rings of crescent-shaped cells were also detected. The anterior ring is located in the border between the fore- and midguts, while the posterior ring is situated between the mid- and hindguts...
December 14, 2018: Arthropod Structure & Development
Qing-Xiao Chen, Wen-Liang Li, Ying-Wu Chen, Jing Chen, Yue-Qing Song
Proboscides are important feeding devices for most adult Lepidoptera and exhibit significant morphological modifications and types of sensilla associated with feeding habits. In this study the architectures of the proboscides and sensilla were compared between the cotton bollworm Helicoverpa armigera (Hübner) and the armyworm Mythimna separate (Walker) using scanning electron microscopy. The proboscides of both species consist of two elongated maxillary galeae joined by dorsal and ventral legulae, forming a food canal...
December 11, 2018: Arthropod Structure & Development
A A Tellez-Garcia, R Bello-Bedoy, J N Enríquez-Vara, A Córdoba-Aguilar, A E Gutiérrez-Cabrera
Triatomines (Heteroptera: Reduviidae) include around 139 species, widely known as vectors of Chagas disease. Our aim is to review the existing knowledge of the genital morphology and sexual behavior and provide some functional analysis of these traits in triatomines. A complex set of traits comprise genitalia and these are highly variable among species. The components of the phallus and seminal products (secreted by action of testes and two accessory glands) interact to allow successful sperm transfer to the female spermathecae (usually a pair of blind tubes that emerge from the common oviduct)...
December 6, 2018: Arthropod Structure & Development
Hans Pohl, Rolf G Beutel
In this review the presently available morphological data on primary larvae of Strepsiptera are interpreted with respect to effects of miniaturization, but also their possible functional or phylogenetic background. The morphology of the 1st instars is mainly affected by functional constraints linked with parasitism but also by very distinct effects of miniaturization. The latter include modifications of the cephalic cuticle, the extremely limited free space in the body lumen, the shift of origins of cephalic muscles to the thorax, a reduced number of cephalic and thoracic muscles, extensions of muscles with cell bodies and other organelles, and an extreme concentration of the entire central nervous system in the middle region of the body...
November 27, 2018: Arthropod Structure & Development
Andrey B Shatrov, Elena V Soldatenko, Vitaliy A Stolbov, Petr A Smirnov, Olga A Petukhova
This study is the first attempt to describe the ultrastructure and functional morphology of the dermal glands in Limnochares aquatica (L., 1758). The dermal glands were studied using light-optical, SEM and TEM microscopy methods during different stages of their activity. In contrast to the vast majority of other fresh water mites, dermal glands of the studied species are originally multiplied and scattered freely at the mite body surface. The opening of the glands is saddle-like, formed of several tight cuticular folds and oriented freely to the long axis of the mite body...
November 26, 2018: Arthropod Structure & Development
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