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1.
Zoolog Sci ; 41(2): 167-176, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38587911

RESUMEN

The treehoppers (Hemiptera, Membracidae) are known for possessing a large three-dimensional structure called a helmet. Although some ecological functions of the helmet have already been elucidated, the developmental mechanisms underlying the complex and diverse morphology of the helmet are still largely unknown. The process of helmet formation was first described in Antianthe expansa, which possesses a simple roof-shaped helmet. However, the developmental process in species with more complex helmet morphologies remains largely unexplored. Hence, in this study, we used Poppea capricornis, which possesses a more complex helmet structure than A. expansa, to investigate the helmet development using paraffin sections, micro-CT, and scanning electronic microscopy. Our focus was on the overall helmet developmental process common to both species and formation of structures unique to Poppea and its comparison to Antianthe. As a result, we discovered that miniature structures were also formed in Poppea, similar to Antianthe, during the helmet formation. Common structures that were shared between the two species were discernible at this stage. Additionally, we observed that suprahumeral horns and posterior horns, two morphological traits specific to the Poppea helmet that are apparently similar anatomically, are formed through two distinctly different developmental mechanisms. The suprahumeral horns appeared to be formed by utilizing the nymphal suprahumeral bud as a mold, while we could not detect any nymphal structures potentially used for a mold in the posterior horns formation. Our findings suggest that the helmet formation mechanisms of Antianthe and Poppea employ a common mechanism but form species-specific structures by multiple mechanisms.


Asunto(s)
Hemípteros , Animales , Dispositivos de Protección de la Cabeza , Especificidad de la Especie
2.
JCEM Case Rep ; 1(4): luad090, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37908992

RESUMEN

Solid pseudopapillary tumor (SPT) is a low-grade malignant tumor of the pancreas. SPT typically affects women and can occur in ectopic pancreatic region; however, it also occurs rarely in retroperitoneum. The tumor may be bulky at the time of diagnosis since there is no specific clinical manifestation. Here we present an older male case with retroperitoneal SPT. A 67-year-old man consulted for intermittent fever and lumbago. His basal hormonal profile screened out a functional tumor. Computed tomography (CT) showed a gigantic mass in his left adrenal region. A normal left adrenal gland was not identified, and the tumor's feeding artery was recognized as the left adrenal artery by the contrast-enhanced CT. Adrenal malignant tumor was suspected, and tumor resection was performed. The resected tumor size was 15 × 10 × 9 cm. Histologically, epithelial-like cells with round nuclei and a small amount of eosinophilic cytoplasm proliferated in papillary (around the blood vessels) or uniformly solid form. By immunostaining, tumor cells were vimentin, CD56, cytokeratin AE1/AE3, CD10, ß-catenin in the nucleus, cyclin D1, and PgR positive. These findings led to the diagnosis of SPT. Although rare, SPT should be considered as a differential diagnosis in cases of a mass arising from the adrenal region.

3.
Zookeys ; 1177: 87-146, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37692321

RESUMEN

Animal constructions are the outcomes of complex evolutionary, behavioural, and ecological forces. A brief review of diverse animal builders, the materials used, and the functions they provide their builders is provided to develop approaches to studying faecal-based constructions and faecal-carrying in leaf beetles (Coleoptera: Chrysomelidae). Field studies, rearing, dissections, photography, and films document shields constructed by larvae in two species in two tribes of the subfamily Cassidinae, Calyptocephalaattenuata (Spaeth, 1919) (Spilophorini), and Cassidasphaerula Boheman, 1853 (Cassidini). Natural history notes on an undetermined Cassidini species and Stolascucullata (Boheman, 1862) (Tribe Mesomphaliini) outline the life cycle of tortoise beetles and explain terms. Commonly, the cassidine shield comprises exuviae onto which faeces are daubed, producing a pyramidal-shaped shield that can cover most of the body (up to the pronotum). In Cal.attenuata the larval shield comprises only exuviae, while in Cass.sphaerula, instar 1 initiates the shield by extending its telescopic anus to apply its own faeces onto its paired caudal processes; at each moult the exuvia is pushed to the caudal process base but remains attached, then more faeces are applied over it. The larva's telescopic anus is the only tool used to build and repair the shield, not mouthparts or legs, and it also applies chemicals to the shield. Pupae in Cal.attenuata retain part of the exuviae-only shield of instar VI, while pupae in Cass.sphaerula retain either the entire 5th instar larval shield (faeces + all exuviae) or only the 5th larval exuvia. The caudal processes are crucial to shield construction, shield retention on the body, and as materials of the central scaffold of the structure. They also move the shield, though the muscular mechanism is not known. Altogether the faecal + exuviae shields may represent a unique morpho-behavioural synapomorphy for the crown-clade Cassidinae (10 tribes, ~ 2669 species) and may have been a key innovation in subsequent radiation. Defensive shields and domiciles may help explain the uneven radiation of chrysomelid subfamilial and tribal clades.

4.
Jpn J Clin Oncol ; 53(11): 1009-1018, 2023 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-37626447

RESUMEN

Alveolar soft part sarcoma is a rare neoplasm of uncertain histogenesis that belongs to a newly defined category of ultra-rare sarcomas. The neoplasm is characterized by a specific chromosomal translocation, der (17) t(X; 17)(p11.2;q25), that results in ASPSCR1-TFE3 gene fusion. The natural history of alveolar soft part sarcoma describes indolent behaviour with slow progression in deep soft tissues of the extremities, trunk and head/neck in adolescents and young adults. A high rate of detection of distant metastasis at presentation has been reported, and the most common metastatic sites in decreasing order of frequency are the lung, bone and brain. Complete surgical resection remains the standard treatment strategy, whereas radiotherapy is indicated for patients with inadequate surgical margins or unresectable tumours. Although alveolar soft part sarcoma is refractory to conventional doxorubicin-based chemotherapy, monotherapy or combination therapy using tyrosine kinase inhibitors and immune checkpoint inhibitors have provided antitumor activity and emerged as new treatment strategies. This article provides an overview of the current understanding of this ultra-rare sarcoma and recent advancements in treatments according to the clinical stage of alveolar soft part sarcoma.


Asunto(s)
Sarcoma de Parte Blanda Alveolar , Neoplasias de los Tejidos Blandos , Adolescente , Adulto Joven , Humanos , Sarcoma de Parte Blanda Alveolar/genética , Sarcoma de Parte Blanda Alveolar/terapia , Sarcoma de Parte Blanda Alveolar/diagnóstico , Proteínas de Fusión Oncogénica/genética , Neoplasias de los Tejidos Blandos/tratamiento farmacológico , Neoplasias de los Tejidos Blandos/genética , Translocación Genética , Terapia Combinada
5.
Cell Rep ; 42(8): 112917, 2023 08 29.
Artículo en Inglés | MEDLINE | ID: mdl-37537843

RESUMEN

A previously undescribed mechanism underlying butterfly wing coloration patterns was discovered in two distantly related butterfly species, Siproeta stelenes and Philaethria diatonica. These butterflies have bright green wings, but the color pattern is not derived from solid pigments or nanostructures of the scales or from the color of the cuticular membrane but rather from a liquid retained in the wing membrane. Wing structure differs between the green and non-green areas. In the non-green region, the upper and lower cuticular membranes are attached to each other, whereas in the green region, we observed a space of 5-10 µm where green liquid is held and living cells are present. A pigment analysis and tracer experiment revealed that the color of the liquid is derived from hemolymph components, bilin and carotenoid pigments. This discovery broadens our understanding of the diverse ways in which butterfly wings obtain their coloration and patterns.


Asunto(s)
Mariposas Diurnas , Nanoestructuras , Animales , Pigmentación , Alas de Animales , Membranas
7.
Acta Med Okayama ; 77(3): 323-330, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37357634

RESUMEN

In the current World Health Organization classification of central nervous system tumors, comprehensive genetic and epigenetic analyses are considered essential for precise diagnosis. A 14-year-old male patient who presented with a cerebellar tumor was initially diagnosed with glioblastoma and treated with radiation and concomitant temozolomide chemotherapy after resection. During maintenance temozolomide therapy, a new contrast-enhanced lesion developed in the bottom of the cavity formed by the resection. A second surgery was performed, but the histological findings in specimens from the second surgery were different from those of the first surgery. Although genome-wide DNA methylation profiling was conducted using frozen tissue for a precise diagnosis, the proportion of tumor cells was insufficient and only normal cerebellum was observed. We then performed comprehensive genetic analysis using formalin-fixed paraffin-embedded sections, which revealed MYCN amplification without alteration of IDH1, IDH2, or Histone H3. Finally, the patient was diagnosed with pediatric-type diffuse high-grade glioma, H3-wildtype and IDH-wildtype. In conclusion, comprehensive genetic and epigenetic analysis should be considered in pediatric brain tumor cases.


Asunto(s)
Neoplasias Encefálicas , Glioma , Masculino , Humanos , Niño , Adolescente , Temozolomida , Mutación , Glioma/diagnóstico , Glioma/genética , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Genómica
8.
Acta Med Okayama ; 77(2): 215-220, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37094961

RESUMEN

Among patients with transient abnormal myelopoiesis (TAM) associated with Down syndrome, approximately 20% die within 6 months from multiorgan failure, especially liver fibrosis. We experienced three children with TAM who had low white blood cell counts but increased bilirubin levels. Here, we discuss the detailed clinical courses of these patients, including the pathological findings of liver biopsies. Our cases, together with previous literature, suggest that liver biopsy can be performed safely and provides useful information, especially regarding disease activities, and that low-dose cytarabine is a reasonable option to prevent early death in TAM patients with liver dysfunction.


Asunto(s)
Síndrome de Down , Niño , Humanos , Síndrome de Down/complicaciones , Citarabina , Hígado , Biopsia
9.
Int J Gynecol Pathol ; 42(1): 63-67, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-35075047

RESUMEN

Endometrial carcinoma with hepatoid differentiation is rare and <20 reported cases have been reported as endometrial hepatoid carcinoma (EHC). We present a case of EHC associated with serous carcinoma in a 76-yr-old Japanese woman. The hepatoid component showed trabecular, pseudoglandular, and diffuse proliferation of hepatoid cells. The hepatoid cells were positive for α-fetoprotein, Hep-Per-1, glypican 3, and HNF-1ß, weakly and focally positive for SALL4, and negative for PAX8. Both of the serous and hepatoid components showed overexpression of p53. The serum α-fetoprotein on postoperative day 5 was 3691 ng/mL. The postoperative course has remained uneventful for 4 yr. These findings suggested that EHC developed from serous carcinoma by acquiring hepatocytic features and losing Müllerian features. Both serous and hepatoid components showed p53 overexpression, suggesting they share a TP53 mutation as a common primary driver.


Asunto(s)
Adenocarcinoma , Neoplasias Endometriales , Femenino , Humanos , alfa-Fetoproteínas , Proteína p53 Supresora de Tumor/genética , Adenocarcinoma/patología , Neoplasias Endometriales/genética , Hepatocitos/patología
10.
Auris Nasus Larynx ; 50(5): 821-826, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36585284

RESUMEN

Low-grade papillary Schneiderian carcinoma (LGPSC) is a rare and newly described type of cancer arising from the Schneiderian epithelium. Owing to cellular atypia, it is difficult to differentiate this type from other papillomas and malignancies. Although this condition remains unclear, it is associated with mortality and recurrence. Therefore, treating physicians should be aware of the possibility of LGPSC for prompt diagnosis and treatment. In this article, we present an additional case of nasopharyngeal LGPSC with cervical lymph node metastasis and reviewed the 14 cases reported thus far in the literature. A 76-year-old female was referred to our department for detailed examination of nasopharyngeal and cervical lymph node tumors detected by positron emission tomography-computed tomography. Based on the biopsy of the nasopharyngeal tumor, we suspected LGPSC. Considering the clinical course and pathological findings, the patient was diagnosed with cervical lymph node metastasis through neck dissection. We performed radiotherapy for the primary lesion of the nasopharynx, which led to the disappearance of the tumor. After 13 months following the radiotherapy, the patient died from a recurrence of retroperitoneal liposarcoma without the recurrence of LGPSC.


Asunto(s)
Carcinoma , Neoplasias Nasofaríngeas , Neoplasias de la Tiroides , Femenino , Humanos , Anciano , Neoplasias Nasofaríngeas/diagnóstico por imagen , Neoplasias Nasofaríngeas/terapia , Metástasis Linfática/patología , Carcinoma/patología , Cuello/patología , Ganglios Linfáticos/patología , Nasofaringe/diagnóstico por imagen , Nasofaringe/patología , Neoplasias de la Tiroides/patología
11.
Intern Med ; 61(8): 1189-1195, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-34645754

RESUMEN

A 61-year-old man with a history of total gastrectomy for cancer with Roux-en-Y reconstruction showed severe postprandial hypoglycemia accompanied by endogenous hyperinsulinemia. Abdominal ultrasonography and contrast-enhanced computed tomography showed no abnormal findings in the pancreas. A selective arterial secretagogue injection test showed the marked induction of serum immunoreactive insulin when calcium was injected into the splenic artery. A pathological analysis following distal pancreatectomy with splenectomy revealed a pancreatic neuroendocrine microadenoma containing insulin-producing cells in the resected pancreas. This case highlights the importance of carefully evaluating refractory and severe hypoglycemia in patients with a history of gastric surgery to exclude insulinoma.


Asunto(s)
Derivación Gástrica , Hipoglucemia , Insulinoma , Neoplasias Pancreáticas , Derivación Gástrica/efectos adversos , Humanos , Hipoglucemia/etiología , Insulina , Insulinoma/complicaciones , Insulinoma/diagnóstico , Insulinoma/cirugía , Masculino , Persona de Mediana Edad , Pancreatectomía/métodos , Neoplasias Pancreáticas/complicaciones , Neoplasias Pancreáticas/cirugía
12.
Zootaxa ; 5208(1): 1-72, 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-37045408

RESUMEN

The genus Pterinoxylus Serville, 1838 is redescribed and revised at the species level. It is distributed throughout most of Central America, the northern half of South America and also has one species on the Lesser Antilles. Detailed descriptions, notes on intraspecific variability and illustrations are provided for all six known species. Keys are presented to distinguish males, females and eggs. Two new species are described from Costa Rica: P. cocoense n. sp. from both sexes and the eggs and P. speciosus n. sp. from both sexes. The female of P. perarmatus (Redtenbacher, 1908) is described and illustrated for the first time, as are the eggs of the type-species P. eucnemis Serville, 1838 and P. perarmatus (Redtenbacher, 1908). The external morphology of all species shows considerable intraspecific variability, which is discussed and illustrated. While P. cocoense n. sp. is an endemic and the only stick insects that has so far become known from Cocos Island a small island some 550 km off the Costa Rican Pacific coast, all other species appear to have fairly wide distributional ranges. Maps show the distributions of all six known species. Type-specimens of the two newly described species are deposited in the collections of MNCR-A (Costa Rica) and Zoologisches Museum und Universität, Hamburg, Germany (ZMUH).


Asunto(s)
Neoptera , Masculino , Femenino , Animales , Costa Rica
13.
Artículo en Inglés | MEDLINE | ID: mdl-34501626

RESUMEN

Drone audition techniques are helpful for listening to target sound sources from the sky, which can be used for human searching tasks in disaster sites. Among many techniques required for drone audition, sound source tracking is an essential technique, and thus several tracking methods have been proposed. Authors have also proposed a sound source tracking method that utilizes multiple microphone arrays to obtain the likelihood distribution of the sound source locations. These methods have been demonstrated in benchmark experiments. However, the performance against various sound sources with different distances and signal-to-noise ratios (SNRs) has been less evaluated. Since drone audition often needs to listen to distant sound sources and the input acoustic signal generally has a low SNR due to drone noise, making a performance assessment against source distance and SNR is essential. Therefore, this paper presents a concrete evaluation of sound source tracking methods using numerical simulation, focusing on various source distances and SNRs. The simulated results captured how the tracking performance will change when the sound source distance and SNR change. The proposed approach based on location distribution estimation tended to be more robust against distance increase, while existing approaches based on directional estimation tended to be more robust against decreasing SNR.


Asunto(s)
Ruido , Sonido , Acústica , Simulación por Computador , Audición , Humanos
14.
Case Rep Gastrointest Med ; 2021: 6617370, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33728073

RESUMEN

In this report, we describe a patient with myoepithelial hamartoma, which is regarded as synonymous with adenomyosis and heterotopic pancreas. Endoscopy revealed a submucosal tumor in the antrum of the stomach. Subsequently, distal gastrectomy with Roux-en-Y reconstruction was performed. Histological findings of adenomyomatous lesion and heterotopic pancreatic tissue were observed in this lesion. The distribution of OCT4, which is a pluripotency marker, varied in each part.

15.
Zookeys ; 1011: 73-84, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33551651

RESUMEN

The male of Xystromutilla bucki Suárez, 1960 is described and associated with the female based on couples reared from trap-nests occupied by Auplopus subaurarius Dreisbach, 1963 (Hymenoptera: Pompilidae). Information on the diapause of X. bucki and Pseudomethoca nr. chontalensis (Cameron, 1895) (Hymenoptera: Mutillidae) is presented. Seasonal and annual variation in the abundance of X. turrialba Casal, 1969 are also given.

16.
Pancreatology ; 21(3): 622-629, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33640249

RESUMEN

BACKGROUND AND AIMS: The subtypes of intraductal papillary mucinous neoplasms (IPMNs) are closely associated with the clinicopathological behavior and recurrence after surgical resection. However, there are no established non-invasive methods to confirm the subtypes of IPMNs without surgery. The aim of this study is to predict the subtypes of IPMNs using the findings of endoscopic ultrasonography (EUS). METHODS: Sixty-two consecutive patients with IPMNs who underwent EUS before surgery were retrospectively reviewed. The following EUS findings were analyzed and their relationship with the subtypes was evaluated: diameter of the main pancreatic duct, cyst size, number of cysts, height of mural nodule, early chronic pancreatitis (CP) finding, fatty parenchyma and atrophic parenchyma. RESULTS: The subtypes of IPMNs were as follows: gastric (G)-type 38 (61%), intestinal (I) -type 14 (23%) and pancreatobiliary (PB) -type 10 (16%). Fatty parenchyma was significantly associated with G-type (P < 0.0001). Early CP findings ≥2 and atrophic parenchyma were significantly correlated with I-type (P < 0.0001). PB-type was significantly associated with pancreatic parenchyma without early CP findings or fatty degeneration in comparison to the other subtypes (P < 0.0001). Using the above characteristic EUS findings, the sensitivity, specificity, and accuracy were as follows: 63%, 92% and 74%, respectively, in G-type, 57%, 96% and 87% in I-type, and 90%, 94% and 94% in PB-type. CONCLUSIONS: The evaluation of EUS findings, especially focused on the pancreatic parenchyma, has the potential to predict the subtypes of IPMN.


Asunto(s)
Endosonografía , Páncreas/diagnóstico por imagen , Neoplasias Intraductales Pancreáticas/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Páncreas/patología , Neoplasias Intraductales Pancreáticas/clasificación , Neoplasias Intraductales Pancreáticas/patología , Estudios Retrospectivos , Sensibilidad y Especificidad
17.
Intern Med ; 60(12): 1941-1947, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33456044

RESUMEN

Due to its rarity and the limited literature, the clinicopathological characteristics of peripheral nerve involvement in immunoglobulin G4 (IgG4)-related disease are unknown. We present two cases of IgG4-related disease, accompanied by peripheral neuropathy, presenting as unilateral ptosis (case 1) and sclerosing cholangitis (case 2), respectively. In both cases, sural nerve biopsy indicated vasculitis as the underlying pathophysiology; the peripheral neuropathy was refractory to corticosteroid therapy. In contrast to the previously proposed pathomechanism of IgG4-related neuropathy (direct lymphoplasmacytic infiltration), the pathological findings in our cases suggest that vasculitis occurs secondary to systemic autoimmune conditions.


Asunto(s)
Enfermedades Autoinmunes , Colangitis Esclerosante , Enfermedad Relacionada con Inmunoglobulina G4 , Enfermedades del Sistema Nervioso Periférico , Vasculitis , Humanos , Inmunoglobulina G , Enfermedad Relacionada con Inmunoglobulina G4/complicaciones , Enfermedad Relacionada con Inmunoglobulina G4/diagnóstico , Enfermedades del Sistema Nervioso Periférico/complicaciones , Enfermedades del Sistema Nervioso Periférico/diagnóstico
18.
Eur J Radiol Open ; 7: 100289, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33318968

RESUMEN

OBJECTIVE: To determine the phase that facilitates flap observation of the ascending aorta in Stanford type A acute aortic dissection with perfused false lumen. METHODS: We reconstructed retrospective Electrocardiogram-gated Computed Tomography Angiography images of the ascending aorta of all 20 patients to 20 phases of curved-multiplanar reconstruction in 5% increment. One radiologist created and randomized 10 cross-sectional images of each phase for every patient and two radiologists scored these images on a 5-point scale depending on the degree of flap stoppage. We calculated the average score for each phase of each case and compared them among the three groups. RESULTS: Image scores were significantly better in the 65 %-100 % R-R interval group than those in the 5%-30 % (p < 2e-16) and 35 %-60 % R-R interval groups(p = 7.2e-10). Similar scores were observed in the Heart Rate > 70 group (p = 0.00039, 2.2e-14). Moreover a similar tendency was observed in the arrhythmia group (p = 0.0035, 0.294). No difference was found in the degree of flap stoppage in the 65 %-100 % R-R interval group between the Heart Rate > 70 and Heart Rate ≤ 70 groups (p = 0.466) and between the arrhythmia and non-arrhythmia groups (p = 0.1240). CONCLUSION: In observing the ascending aorta, We obtained a good image at 65 %-100 % R-R interval and similar tendency was observed in the patients with arrhythmia.

19.
IDCases ; 21: e00856, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32518756

RESUMEN

Perihepatitis is mainly caused by a direct extension of pelvic inflammatory disease, in which the causative pathogen is typically Neisseria gonorrhoeae or Chlamydia trachomatis. We herein discuss the case of a 61-year-old female patient who presented with a fever and right upper quadrant pain. Perihepatitis was diagnosed by contrast-enhanced computed tomography. She had no previous history of sexual activity, genital symptoms, remarkable physical findings or examination results indicative of pelvic inflammatory disease or other diseases. A blood culture detected Streptococcus pneumoniae, leading to the suspicion of hematogeneous dissemination. The patient was therefore treated with the appropriate antimicrobials. While invasive pneumococcal disease mainly results in bacteremic pneumonia, meningitis or endocarditis, the present case showed that it can also lead to perihepatitis; a blood culture is therefore useful for clarifying the infection route and pathogens in perihepatitis if the patient has no past history of sexual activity, genital symptoms or physical or other findings indicative of pelvic inflammatory disease.

20.
Zoological Lett ; 6: 3, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32123574

RESUMEN

Some insects possess complex three-dimensional (3D) structures that develop under the old cuticle prior to the last imaginal molt. Adult treehoppers (Insecta: Hemiptera: Auchenorrhyncha: Membracidae) have one such complex 3D structure, known as a helmet, on their dorsal side. The adult helmet likely forms inside the nymphal pronotum during the final instar nymphal stage. Previous morphological studies have reported that the adult helmet is a large, bi-layered, plywood-like structure, whereas the nymphal pronotum is a monolayer, sheath-like structure. The adult helmet is much larger than nymphal helmet. Thus, the emergence of the adult helmet involves two structural transitions: a transition from a monolayer, sheath-like pronotum to a bi-layer, plywood-like helmet, and a transition in size from small to large. However, when, how, and in what order these transitions occur within the nymphal cuticle is largely unknown. To determine how adult helmet development occurs under the nymphal cuticle, in the present study we describe the morphology of the final adult helmet and investigate developmental trajectories of the helmet during the final instar nymphal stage. We used micro-CT, scanning electron microscope and paraffin sections for morphological observations, and used Antianthe expansa as a model species. We found that the structural transition (from monolayer, sheath-like structure to bi-layer, roof-like structure) occurs through the formation of a "miniature" of the adult helmet during the middle stage of development and that subsequently, extensive folding and furrows form, which account for the increase in size. We suggest that the making of a "miniature" is the key developmental step for the formation of various 3D structures of treehopper helmets.

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