Arthropod Structure & Development最新文献

{"title":"Sexual dimorphism and ultrastructure of salivary glands in adult Bittacus cirratus Tjeder, 1956 (Mecoptera: Bittacidae)","authors":"He-Hong Wang,&nbsp;Le-Le He,&nbsp;Jie Zhang,&nbsp;Bao-Zhen Hua","doi":"10.1016/j.asd.2025.101441","DOIUrl":"10.1016/j.asd.2025.101441","url":null,"abstract":"<div><div>Sexual dimorphism is ubiquitous in insects and has been extensively studied across various taxa. However, it remains unclear whether the salivary glands exhibit sexual dimorphism in adult Bittacidae. In this study, a comparative study of salivary glands in adult male and female <em>Bittacus cirratus</em> Tjeder, 1956 was performed using light and transmission electron microscopy. The salivary glands are tubular labial glands in both sexes of <em>B. cirratus</em>, consisting of a salivary pump, a common salivary duct, a pair of efferent ducts, and numerous dichotomously branching secretory tubules. Interestingly, the salivary glands in females contain a pair of small salivary reservoirs, which are not present in the males. The male salivary glands have a significantly larger diameter and more secretory tubules than those in females. In contrast, male secretory cells occupy a minimal volume of the secretory tubule, resulting in a larger secretory lumen that nearly fills the entire tubule. This configuration enhances the storage capacity of the male secretory tubules. Male secretory cells exhibit active autophagy, possibly due to their approaching late life stages. Sexual dimorphism in the salivary glands and the possible reasons are briefly discussed in Bittacidae.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101441"},"PeriodicalIF":1.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrastructural and light/dark adaptational characteristics of the compound eyes in the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)","authors":"Ying Han,&nbsp;Qing-Xiao Chen","doi":"10.1016/j.asd.2025.101449","DOIUrl":"10.1016/j.asd.2025.101449","url":null,"abstract":"<div><div>The fall armyworm, <em>Spodoptera frugiperda</em>, is a highly destructive agricultural pest native to the Americas, becoming a major invasive species worldwide over the past decade. In this study, the ultrastructure of the compound eyes and light/dark adaptational changes in <em>S. frugiperda</em> were investigated using light and transmission as well as scanning electron microscopy. The compound eyes of <em>S. frugiperda</em> are of the superposition type, featuring a clear zone. Each ommatidium contains eight retinula cells, seven of which extend through the clear zone to the basal lamina, while one cell is located near the basal lamina. The clear zone is longer in dark-adapted eyes than in light-adapted eyes. In dark-adapted eyes, the rhabdoms extend through the clear zone, with their distal ends connecting to the crystalline cones. In light-adapted eyes, however, the rhabdoms do not reach the distal region of the clear zone but are instead confined to the proximal level of the clear zone. Although the rhabdom occupation ratio to the retinula remains constant under both light and dark adaptation, the cross-sectional area of the rhabdoms and their associated retinulae is significantly larger under dark adaptation. These ultrastructural and adaptational characteristics were discussed in the context of the moth's activity preferences, particularly its nocturnal behavior.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101449"},"PeriodicalIF":1.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Copulatory mechanics in ghost spiders (Amaurobioidinae, Anyphaenidae) reveals an independent regressive evolution of a key genital trait through functional replacement","authors":"Dante Poy ,&nbsp;Luis N. Piacentini ,&nbsp;Peter Michalik ,&nbsp;Shou-Wang Lin ,&nbsp;Leonel A. Martínez ,&nbsp;Martín J. Ramírez","doi":"10.1016/j.asd.2025.101442","DOIUrl":"10.1016/j.asd.2025.101442","url":null,"abstract":"<div><div>During evolution, the morphology of animal organs can vary drastically, such as the reduction or loss of structures. This phenomenon is recurrent in the male copulatory organs of many spiders, where structures that are usually well-developed, are missing or vestigial in some taxa. One example is the retrolateral tibial apophysis (RTA) of the male pedipalp of the most diverse lineage of spiders, the RTA clade. It frequently performs a key function during genital coupling, which is the first and main mechanical engagement during genital coupling (i.e., primary locking). However, in several lineages the RTA is either lost or reduced, raising questions on how genital coupling is achieved in these taxa, and what are the potential drivers for the regression of the RTA. To address these questions, we used the subfamily Amaurobioidinae (Anyphaenidae) as a model and studied the genital mechanics of nine species with different degrees of RTA size. Genital coupling was reconstructed using microcomputed tomography (micro-CT) data of cryofixed mating pairs, revealing that, except for a species with a prominent RTA, primary locking is solely achieved by inserting the conductor (a male genital sclerite) into one of the female copulatory openings. Our phylogenetic analyses indicate that the RTA has been independently lost or reduced six times in Amaurobioidinae, and that at least one functional replacement of the RTA by the conductor has occurred within the subfamily. We hypothesize that the use of the conductor for primary locking replaced the primary function of the RTA, allowing its repeated regressions.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101442"},"PeriodicalIF":1.7,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143790927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The cuticle of Agnostina (basal Euarthropoda) was three-layered","authors":"Elena B. Naimark ,&nbsp;Stanislav Yu Chaika","doi":"10.1016/j.asd.2025.101447","DOIUrl":"10.1016/j.asd.2025.101447","url":null,"abstract":"<div><div>The cuticle of four Agnostina families is notably complex, challenging the previously proposed one-layer model. It consists of three distinct layers, with the outer layer being significantly thicker than the middle and inner layers; two upper layers are laminated. The inner layer is very thin and rests on a base of fibrils arranged in a rhomboidal mesh. Comparative analysis suggests that during evolution, the middle and inner layers have decreased in thickness, leaving the outer layer relatively thick. These distinctive structural features are possibly associated with miniaturization of agnostines. Their cuticle resembles that of chelicerates more than that of crustaceans.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101447"},"PeriodicalIF":1.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tyrosine hydroxylase- and serotonin-immunoreactive neurons in the thoracic ganglia of the Oriental fruit fly, Bactrocera dorsalis","authors":"Tao Lin,&nbsp;Liyun He","doi":"10.1016/j.asd.2025.101444","DOIUrl":"10.1016/j.asd.2025.101444","url":null,"abstract":"<div><div>The thoracic ganglia (TG) of insects are essential neural centers responsible for regulating behaviors such as flight and courtship. These ganglia control thoracic muscle movements through the release of biogenic amines, such as dopamine and serotonin, which modulate motor functions and behavioral outputs. The Oriental fruit fly, <em>Bactrocera dorsalis</em> (Hendel), is a major agricultural pest characterized by strong flight and reproductive capabilities. These traits enable rapid dispersal and population establishment, posing significant threats to crop production. Elucidating the neural mechanisms of flight and mating behaviors in <em>B. dorsalis</em> is crucial for developing effective pest management strategies. However, the functional roles of biogenic aminergic neurons in the TG of this species remain poorly understood. This study aimed to elucidate the role of biogenic amines in regulating flight and courtship behavior by employing immunohistochemical techniques using tyrosine hydroxylase (TH, a rate-limiting enzyme in dopamine biosynthesis) and serotonin (5-hydroxytryptamine, 5-HT) antibodies. Using confocal laser scanning microscopy, we analyzed and identified TH immunoreactive (TH-ir) and 5-HT immunoreactive (5-HT-ir) neurons in the TG. Their axonal projections were reconstructed in three dimensions. We identified 10 5-HT-ir and 10 TH-ir neurons. These neurons were primarily distributed in the ventral regions of the TG, located between adjacent neuromeres. The 5-HT-ir neurons exhibited extensive projections throughout the TG with a bilateral projection pattern. In contrast, TH-ir neurons displayed more restricted projection areas. Notably, the cell bodies and axonal projections of these two neuron types were entirely independent, with no co-localization observed. This study provides a comprehensive map of putative dopaminergic and serotonergic neurons in the TG of <em>B. dorsalis</em>, laying a foundation for future research on their roles in behavioral regulation.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101444"},"PeriodicalIF":1.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The morphology of integumental brochosomes in Cicadellidae (Hemiptera: Auchenorrhyncha)","authors":"Kewei Lyu,&nbsp;Yalin Zhang","doi":"10.1016/j.asd.2025.101445","DOIUrl":"10.1016/j.asd.2025.101445","url":null,"abstract":"<div><div>Brochosomes, secretory microstructures composed of protein-lipid compounds, are synthesized in the Malpighian tubules of leafhoppers (Cicadellidae). These specialized particles play essential biological roles, notably providing hydrophobic protection against environmental contaminants and self-generated honeydew residues.</div><div>This investigation systematically examined the integumental brochosomes morphology in 28 Cicadellidae species representing 12 subfamilies, using optical and scanning electron microscopy (SEM), supplemented by morphological data from 17 additional species extracted from published literature. The resultant comprehensive dataset encompassing 45 species revealed significant morphological divergence in the Hylicinae subfamily relative to other taxa. While most Cicadellidae subfamilies possess submicron-scale brochosomes (&lt;1 μm) with characteristic reticulate surface patterning, Hylicinae specimens exhibited exceptional structural diversity.</div><div>Detailed analysis of 8 Hylicinae species identified 4 distinct brochosomes morphotypes classified by surface architecture: rugose, ruminate, foveate, and reticulate types, with foveate and reticulate predominating. Notably, interspecific variation persisted within morphological categories, manifesting through: (1) dimensional disparities in reticular unit size, (2) quantitative differences in surface depression density, (3) presence/absence of secondary granular protrusions, and (4) continuity patterns of surface ridges. These diagnostic structural features suggest brochosomes morphology may serve as both a phylogenetic marker and an adaptive trait reflecting ecological specialization within leafhopper lineages.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101445"},"PeriodicalIF":1.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innervation of the subgenual organ in the stick insect Trachyaretaon echinatus: Neuroanatomical differences within Oriophasmata (Phasmatodea)","authors":"Johannes Strauß","doi":"10.1016/j.asd.2025.101443","DOIUrl":"10.1016/j.asd.2025.101443","url":null,"abstract":"<div><div>Neuronal features including the nerve pattern are relatively conserved during evolution and are therefore useful for comparative studies. In stick insects (Phasmatodea), neuronal elements are rarely analysed for different groups. As the morphology of this group is characterised by convergent phenotypes, traits of the nervous system may provide additional information on phylogenetic relationships. Here, the innervation for a mechanosensory chordotonal organ, the subgenual organ in the proximal tibia, is documented by axonal tracing. For species of Neophasmatodea, previous studies showed an innervation for the subgenual organ with a single nerve branch in Occidophasmata (New World stick insects) compared to the Oriophasmata (Old World stick insects) where two separate nerve branches occur at the subgenual organ. Here, the innervation pattern is analysed in <em>Trachyaretaon echinatus</em> (Heteropterygidae: Obriminae), as Heteropterygidae are the sister-group to the remaining Oriophasmata. This species was chosen as representative of Heteropterygidae to test for a homogenous and thus likely conserved nerve pattern within Oriophasmata. The innervation of the subgenual organ shows a single nerve branch. Therefore, different innervation patterns occur within Oriophasmata. The innervation with one single nerve documented for <em>T. echinatus</em> is discussed as potentially plesiomorphic for Neophasmatodea.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101443"},"PeriodicalIF":1.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and variability in the female genital atrium of Uropodina (Acari: Parasitiformes)","authors":"Jeremy Naredo ,&nbsp;J. Orlando Combita-Heredia ,&nbsp;Thomas van de Kamp ,&nbsp;Marcus Zuber ,&nbsp;Elias Hamann ,&nbsp;Ma. Magdalena Vázquez ,&nbsp;Hans Klompen","doi":"10.1016/j.asd.2025.101428","DOIUrl":"10.1016/j.asd.2025.101428","url":null,"abstract":"<div><div>Primary and secondary sexual characters of Mesostigmata are often used in species descriptions and phylogenetic analyses. The use of these characters has been focused almost exclusively on external structures. Digital 3D reconstruction based on synchrotron X-ray microtomography (SR-μCT) data allowed a comparative investigation of the structure of an internal system, the female genital atrium, in the mite lineage Uropodina (Parasitiformes: Mesostigmata). Despite substantial variability in observed structures, a general model for the endogynium, vagina, and muscle structure has been generated using a combination of SR-μCT and light microscopy. Most of the variations are hypothesized as related to species recognition and/or manipulation of the endospermatophore. The recorded variability may have substantial phylogenetic value, as a previously unreported modification of the vagina appears to diagnose a substantial lineage of “higher” Uropodina. This set of observations also support the hypothesis that the large family Urodinychidae is polyphyletic. Overall, SR-μCT and 3D reconstruction turned out to be very helpful for studies on internal organ systems in these very small organisms, lessening the need for laborious dissections or extensive Transmission electron microscopy-based investigations.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101428"},"PeriodicalIF":1.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143714796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine structure and adaptive variation of compound eyes in two species of infralittoral prawns (Palaemon, Caridea): New insights into imaging mechanisms of reflecting superposition eyes in decapod crustaceans","authors":"Daniel Hamm ,&nbsp;Stefan Richter ,&nbsp;Carsten H.G. Müller","doi":"10.1016/j.asd.2025.101440","DOIUrl":"10.1016/j.asd.2025.101440","url":null,"abstract":"<div><div>The main goal of this study has been to explore and compare the functional morphology and photoadaptive patterns of the compound eyes of two closely related prawn species both inhabiting different infralittoral visual environments. Using light and transmission electron microscopy we investigated light- and dark-adapted ommatidia of the light-resistant <em>Palaemon elegans</em> and the shade-preferring <em>Palaemon xiphias</em>. Ommatidia of both <em>Palaemon</em> species generally share the same cellular architecture, except for the irregular 8th retinula cell building up the distal rhabdom. This structure functions as UV-light receptor and potential light guide, providing dichroic vision and protection of the subjacent main (banded) rhabdom, formed by the remaining retinula cells 1–7, from harmful UV-radiation. As both the apical 4-lobe system of the 8th cell and the distal rhabdom are much stronger developed in <em>P. elegans</em>, we conclude that different light intensities in the respective photohabitats have led to noticeable micro-evolutionary adaptations at cellular level. In contrast, the main (banded) rhabdom, is capable of perceiving polarized light which is of special photo-ecological benefit for the diurnal <em>P. elegans</em> when populating shallow rock pools.</div><div>The ommatidial ultrastructure of both species is very similar in the dark-adapted state. Many traits support reflecting superposition: such as (1) square corneal facet and crystalline cone, (2) the clear zone along main rhabdoms, (3) a mirror layer established by interommatidial pigment cells, and (4) the proximal tapetum established by reflecting pigment cells below the rhabdom. During light-adaptation, a massive turnover and shift of both organelles or whole cell bodies along the ommatidial optical axis enables the use of functional apposition optics at daytime in both study species. Some major differences in light-adaptation patterns and the assumed efficiency of functional apposition can be explained by adaptations to different light habitats.</div><div>Our TEM study shows that shifting patterns of various pigment granules in interommatidial pigment cells, which occur over light adaptation, are species-specific. As a first measure to protect the main rhabdom from excessive light we identified the super-fast breakdown of a mirror layer around the cone's tip which is made of crystal granules and, thus, widens the aperture of ommatidia in superposition mode at night.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101440"},"PeriodicalIF":1.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sternal glands in Strumigenys ants","authors":"Chu Wang ,&nbsp;Fu-Ya Chung ,&nbsp;Chung-Chi Lin ,&nbsp;Johan Billen","doi":"10.1016/j.asd.2025.101439","DOIUrl":"10.1016/j.asd.2025.101439","url":null,"abstract":"<div><div><em>Strumigenys</em> ants are characterized by an extraordinary developed exocrine system with 10 glands exclusively found in this genus. Making a survey of 18 species, we discovered two additional glands in workers and queens that are located underneath the anterior third of the 6th and 7th sternites. The epithelial glands are formed by cubic to cylindrical cells that have tortuous lateral cell membranes with interdigitations and apical septate junctions, smooth endoplasmic reticulum and apical microvilli. The glands occur in near proximity to the sting base and therefore may display fortifications to protect them against the sting movements during its extrusion and retraction. The external cuticle that covers the gland region displays small transverse grooves and transcuticular channels. The most developed glands were found in workers of the social parasite <em>Strumigenys mutica</em>, although the eventual link with social parasitism remains unclear. In workers of <em>S. sauteri</em> the glands are rudimentary or absent which may be related with prey capture in this species that occurs without use of the sting. Whereas sternal glands in other ants often produce trail pheromones, this role can be excluded in <em>Strumigenys</em> as trail following does not occur in this genus.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":"86 ","pages":"Article 101439"},"PeriodicalIF":1.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}