Alimentary canal formation in the stonefly,Kamimuria tibialis (pictet) (Plecoptera : Perlidae)

The alimentary canal formation in the stonefly, Kamimuria tibialis (Plecoptera : Perlidae) is described. The stomodaeum is formed as in other insect embryos. The proctodaeum is derived from the ectodermal fold an the caudal end of the embryo without the contribution of the amnion. The 3 Malpighian tubules develop from the blind end of the proctodaeum. The rectal pad is formed by the thickening of the dorsal wall of the proctodaeum. The midgut epithelium rudiment arises only from the blind end of the proctodaeum, i.e. it is completed by unipolar formation instead of bipolar. The yolk cells do not contribute to the formation of the midgut epithelium. The alimentary canal is transformed during the 1st nymphal instar and becomes functional in the next instar. The stomodaeum is differentiated into 3 parts: pharynx, oesophagus, and proventriculus. The midgut becomes shortened and its epithelium is well developed. Gastric caeca with tapering processes are formed.     

Micro‐computed tomography visualization of the vestigial alimentary canal in adult oestrid flies

Oestrid flies (Diptera: Oestridae) do not feed during the adult stage as they acquire all necessary nutrients during the parasitic larval stage. The adult mouthparts and digestive tract are therefore frequently vestigial; however, morphological data on the alimentary canal in adult oestrid flies are scarce and a proper visualization of this organ system within the adult body is lacking. The present work visualizes the morphology of the alimentary canal in adults of two oestrid species, Oestrus ovis L. and Hypoderma lineatum (de Villiers), with the use of non‐invasive micro‐computed tomography (micro‐CT) and compares it with the highly developed alimentary canal of the blow fly Calliphora vicina Robineau‐Desvoidy (Diptera: Calliphoridae). Both O. ovis and H. lineatum adults showed significant reductions of the cardia and the diameter of the digestive tract, an absence of the helicoidal portion of the midgut typical of other cyclorrhaphous flies, and a lack of crop and salivary glands. Given the current interest in the alimentary canal in adult dipterans in biomedical and developmental biology studies, further understanding of the morphology and development of this organ system in adult oestrids may provide valuable new insights in several areas of research.     

Characterization of the alimentary canal of the aphidophagous ladybird,Adalia bipunctata (Coleoptera: Coccinellidae): anatomical and histological approaches

The alimentary canal of the two‐spot ladybird Adalia bipunctata (Linnaeus) (Coleoptera: Coccinellidae) presents the foregut (stomodeum), the midgut (mesenteron) and the hindgut (proctodeum). The shortest region is the foregut and the longest is the midgut. The relative proportions of the main regions were found to be similar for males and females. In the foregut it was possible to distinguish the pharynx, the esophagus and the proventriculus but no crop. The hindgut is composed of the ileum, rectum and rectal canal. Generally the organ width is similar for males and females, but females presented a wider proventriculus. The epithelium of the foregut varied from squamous to simple cuboidal and columnar. In the midgut the epithelium is simple columnar with goblet and regenerative cells. The epithelium of the hindgut varied from simple cuboidal to squamous. Females presented thicker midgut epithelium whereas males presented thicker epithelium in the esophagus. The anatomy of the alimentary canal of A. bipunctata seems to conform to its carnivorous and recent phylogenetic status within the family Coccinellidae.     

狭胸天牛成虫和幼虫的消化道研究

研究了狭胸天牛成虫和幼虫消化道形态。成虫消化道细长,嗉囊长囊状,中肠前段具极少的稀疏瘤状小突起。幼虫消化道相当长,前肠细短,中肠很长,前中肠粗短而膨大,中肠表面无小盲囊。     

合哑蝉成虫消化道形态、组织结构及超微结构（英文）

【目的】本研究通过合哑蝉Karenia caelatata成虫消化道的形态学、组织学和超微结构研究,进一步了解蝉科(Cicadidae)代表种类的消化道形态和功能分化。【方法】利用光学显微镜和透射电子显微镜技术,对合哑蝉雄成虫消化道的整体形态以及食道、滤室(中肠前端及后端、马氏管基部、后肠基部)、滤室外中肠(锥形体、中肠环)、后肠(回肠、直肠)的一般形态和超微结构进行了详细观察,同时对滤室的组织结构进行了研究。【结果】结果表明,合哑蝉消化道由食道、滤室、滤室外中肠及后肠组成。食道狭长,被有上表皮和内表皮。中肠前端、中肠后端、马氏管基部以及后肠基部被一肌肉鞘包围形成滤室构造。组成中肠前端和后端的细胞基膜高度内褶,顶端的微绒毛发达。中肠后端分布许多线粒体和高电子密度的分泌颗粒。滤室外的中肠包括膨大的锥形体、中肠环。其中,锥形体由两种细胞组成;中肠环分为前、中、后3个不同的区段。前中肠细胞包含大量的分泌颗粒、线粒体、粗面内质网和溶酶体;中中肠细胞含有分泌颗粒;后中肠细胞包括许多低电子密度的分泌颗粒和滑面内质网。类铁蛋白颗粒零星分布于中肠环的前、中区段。组成锥形体和中肠环前端的细胞顶端微绒毛被...     

黄脸油葫芦消化道和马氏管的组织学观察

应用石蜡切片技术对黄脸油葫芦Teleogryllus emma(Ohmachi and Matsumura)成虫消化道和马氏管的显微结构进行观察。消化道由前肠、中肠和后肠3部分组成:前肠由内向外可分为6层:内膜、肠壁细胞层、底膜、纵肌、环肌和围膜;中肠组织结构也分为6层,即由内向外依次为围食膜、肠壁细胞层、底膜、环肌、纵肌和围膜;后肠的组织结构与前肠基本相似,但内膜比前肠的薄,且肌肉的排列较前肠不规则,与中肠的肌肉排列相似,即环肌在内,纵肌在外。消化道各部位的结构差异与功能有密切关系。马氏管管壁由8个左右形状多变并具有显著细胞核的大形的单层上皮细胞组成。     

桃小食心虫幼虫的消化道和马氏管的显微结构观察

利用光学显微镜和扫描电子显微镜,在形态学和组织学水平上研究_『桃小食心虫 Carposina sasakii 幼虫消化道和屿氏管的结构.桃小食心虫幼虫消化道由前肠、中肠和后肠组成.前肠细短,肌肉层薄.前肠与中肠交界处有突出的胃盲囊.中肠长且粗大,内有围食膜,肠壁细胞较大,外层为发达的环肌和纵肌.后肠上皮细胞内陷很深.6根念珠状的马氏管位于中、后肠分界处.     

Digestive enzymes of leaf-cutting ants, Acromyrmex subterraneus (Hymenoptera: Formicidae: Attini): distribution in the gut of adult workers and partial characterization

Enzyme activities associated with the labial glands, midgut and rectum of adult Acromyrmex subterraneus were investigated in order to understand their role in digestion of plant and fungal material. High chitinolytic activity was detected in the labial glands, indicating a possible role in the degradation of fungus ingested by the ants. Chitinolytic activity seen in other compartments of the alimentary canal probably originated in the labial glands. The highest activity detected in the midgut was for alpha-glucosidase, which was considered to be of insect origin due to its association with midgut epithelium and it is probably involved in glucose assimilation from nutrient sources such as maltose and sucrose present in plant material. A large range of enzyme activities were detected in the rectal lumen contents, and as in the midgut the highest values were for alpha-glucosidase activity. The absence of activity associated with the epithelium, in the particulate fraction, indicates that the rectal epithelium does not have a secretory function. The detection of enzymes in the rectal lumen contents, which were not detected in the midgut lumen contents, indicates that the rectum acts as a reservoir, accumulating enzymes. The major digestive enzymes were partially characterized using hydrophobic interaction chromatography, gel filtration and SDS-PAGE. The pH of the adult intestinal tract and flow rate of dye through the tract was investigated. A gradual acidification of the intestinal tract was noted commencing with the crop (pH 6-8.2) and terminating with the rectum (pH 3-5). The flow of dye through the different compartments of the tract showed a rapid fill time for all the gut compartments and a short residence time in the crop. In all other compartments, the dye remained detectable for 10 days or longer.     

Digestive, salivary, and reproductive organs of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B type

A microscopic analysis of the morphology and ultrastructure of the digestive, salivary, and reproductive systems of adult Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B type was conducted using light, scanning, and transmission electron microscopy. The internal anatomy of B. tabaci was found to be similar to that reported for Trialeurodes vaporariorum. In a microscopic analysis of the salivary glands, we have shown that each primary salivary gland is composed of at least 13 cells varying in morphology and staining differentially, while the accessory salivary glands are composed of four morphologically similar cells. We analyzed the course of the alimentary canal in B. tabaci, demonstrated the internal morphology of the organs, and clarified the location of the filter chamber relative to other organs in the whitefly. Our observations confirm that the pair of structures extending from the connecting chamber are caeca that may aid in fluid movement through the midgut and are not Malpighian tubules, as previously suggested. We confirm an earlier finding that the whitefly lacks Malpighian tubules, having instead specialized Malpighian-like cells within the filter chamber at the juncture with the internal ileum. Finally, we provide the first scanning electron microscopic analysis showing the reproductive organs of B. tabaci. Our investigation provides clarified terminology for several components of the digestive and excretory system. We also provide drawings and micrographs that will aid future researchers in localizing the internal organs of B. tabaci. We expect our analysis to provide a valuable tool for studying B. tabaci / plant virus interactions and physiological and biological aspects of this insect.     

长足大竹象消化道不同分段菌群异质性及竹木质纤维素降解能力

[目的]长足大竹象Cyrtotrachelus buqueti消化道共生菌群参与了竹纤维素的降解.本研究旨在揭示长足大竹象幼虫消化道不同分段共生菌群异质性及木质纤维素的降解能力.[方法]通过对16S rRNA测序对长足大竹象幼虫消化道分段口器(YB)、前肠(YFG)、中肠(YMG)和后肠(YHG)进行菌群组成分析及功能...     

Metaparasitylenchus hypothenemi n. sp. (Nematoda: Allantonematidae), a parasite of the coffee berry borer, Hypothenemus hampei (Curculionidae: Scolytinae)

Metaparasitylenchus hypothenemi n. sp. (Nematoda: Allantonematidae) is described from the coffee berry borer, Hypothenemus hampei (Ferrari) (Curculionidae: Scolytinae), in Chiapas, Mexico. This species differs from other members of the genus by its small size, annulated cuticle, lateral fields with 3 ridges, free-living stages with an excretory pore located between the pharyngeal gland orifices, a distinct stylet with basal swellings in free-living females, a postvulval uterine extension, a thin stylet lacking basal swellings in males, 2 separate spicules, a gubernaculum, and a peloderan bursa. Parasitic females are white, with a straight or slightly curved body and are ovoviviparous. Third-stage juveniles emerge from parasitized beetles and molt twice before reaching the adult stage. Because the coffee berry borer is the most important pest of coffee throughout the world and this parasite partially or completely sterilizes female beetles, it is worthy of further investigation as a potential biological control agent.     

Ultrastructural features of the midgut epithelium of females Lutzomyia intermedia (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae).

A morphological study of the midgut of Lutzomyia intermedia, the primary vector of cutaneous leishmaniasis, in southeast Brazil, was conducted by light, scanning and transmission electron microscopy. The midgut is formed by a layer of epithelium of columnar cells on a non-cellular basal lamina, under which there is a musculature, which consists of circular and longitudinal muscular fibers. A tracheolar network is observed surrounding and penetrating in the musculature. Females were examined 12, 24, 48, 72 h and 5 days following a blood meal and were analyzed comparatively by transmission electron microscopy with starved females. In starved females, the epithelium of both the anterior and posterior sections of the midgut present whorl shaped rough endoplasmic reticulum. The posterior section does not present well-developed cellular structures such as mitochondria. Observations performed at 12, 24, 48 and 72 h after the blood meal showed morphological changes in the cellular structures in this section, and the presence of the peritrophic matrix up to 48 h after the blood meal. Digestion is almost complete and a few residues are detected in the lumen 72 h after blood feeding. Finally, on the 5th day after the blood meal all cellular structures present the original feature resembling that seen in starved sand flies. Morphometric data confirmed the morphological observations. Mitochondria, nuclei and microvilli of midgut epithelial cells are different in starved and blood fed females. The mitochondria present a similar profile in the epithelium of both the anterior and posterior section of the midgut, with higher dimension in starved females. The cell microvilli in the posterior section of the midgut of starved females are twice the size of those that had taken a blood meal. We concluded that there are changes in the midgut cellular structures of L. intermedia during the digestion of blood, which are in agreement with those described for other hematophagous diptera.     

Ultrastructure of alimentary tract formation in embryos of two insect species: Melasoma saliceti and Chrysolina pardalina (Coleoptera, Chrysomelidae)

Embryogenesis of the alimentary tract in two chrysomelid species (Chrysolina pardalina and Melasoma saliceti) is described. The embryonic development of both species lasts 7days at room temperature. Stomodaeum and proctodaeum invaginate at the anterior and posterior ends of the germ band. Together with the ectodermal tissue the endoderm cells also enter into the embryo. The anterior and posterior parts of the alimentary tract wedge into the yolk in the form of conical structures. The endodermal cells remain at the yolk surface and start migration over the yolk mass as two lateral bands of cells. The endoderm is always accompanied by mesoderm. On the fifth day of development the endodermal cells together with the mesoderm layer spread over the ventral and dorsal sides of the yolk mass and form the single layered primordium of the midgut epithelium. On the sixth day of development a basal lamina appears between the endoderm and the mesoderm cells and differentiation of both tissues starts. The endodermal epithelium cells change shape from flat to cuboidal and eventually into columnar. Mesoderm cells differentiate into muscle and tracheae. On the 7thday of development stomodaeum and proctodaeum become lined with cuticle and the midgut becomes covered with microvilli. The yolk cells populating the yolk mass do not contribute to midgut formation in the species studied.     

The alimentary canal of <Emphasis Type="Italic">Blomia tropicalis</Emphasis> (Acari: Astigmata: Echymopodidae): the application of three-dimensional reconstruction technology

The domestic mite species Blomia tropicalis is an important indoor allergen source related to asthma and other allergic diseases in tropical and subtropical regions. Here, we describe the alimentary canal of B. tropicalis with the particular application of three-dimensional reconstruction technology. The alimentary canal of B. tropicalis resembles the typical acarid form consisting of the cuticle-lined foregut and hindgut separated by a cuticle-free midgut. The foregut is divided into a muscular pharynx and an esophagus. The midgut is composed of a central ventriculus, two lateral caeca, a globular colon and a postcolon with two tubiform postcolonic diverticula. The most common cells forming the epithelium of ventriculus and caeca are squamous and cuboidal. The globular cells contain a big central vacuole in the posterior region of the caeca. The epithelium of the colon and postcolon has significantly longer microvilli. The anal atrium is a simple tube with flattened epithelial cells. The spatial measurements of the three-dimensional model suggest that the paired caeca and central ventriculus occupy 55.1 and 34.6%, respectively, of the total volume of the alimentary canal and may play the key role in food digestion. J. Wu and F. Yang contributed equally.     

美国白蛾幼虫消化道形态和超微结构观察

美国白蛾Hyphantria cunea Drury是我国重要的林业检疫性害虫之一,世界范围内寄主多达600余种,对我国林业生产和生态环境建设造成了巨大损失。明确美国白蛾幼虫消化道各部分的形态结构,可为进一步研究其幼虫的食性及消化机能奠定基础。利用光学显微镜、扫描电子显微镜与透射电子显微镜观察了美国白蛾6龄幼虫消化道形态及超微结构。美国白蛾幼虫的消化道由前肠、中肠、后肠组成。前肠是消化道最长的部分,占整个消化道的54.27%,包括咽、食道、嗉囊、前胃四部分;中肠较短,占整个消化道的21.28%,内部具围食膜;后肠由幽门、回肠、结肠和直肠组成,幽门由幽门锥和幽门瓣组成。马氏管共6条,丝腺2条。美国白蛾幼虫消化道总体结构大部分鳞翅目消化道结构相似,但是其前肠在长度上发生了较大的变异,本文进一步讨论了美国白蛾幼虫消化道结构与其食性及耐饥饿能力等的相关性。     

太白蝎蛉消化道形态学与组织学研究

利用光学显微镜和扫描电子显微镜, 在形态学和组织学水平上研究了太白蝎蛉Panorpa obtusa Cheng成虫消化道的结构。结果表明： 蝎蛉消化道由前肠、中肠、和后肠组成。前肠包括咽喉、食道、和前胃, 但没有嗉囊,其中咽喉可分为骨化的前咽和附着扩肌的后咽（咽喉唧筒）; 前胃壁很厚,内膜上长有许多排列整齐、紧密的棕色胃刺,司过滤、暂时储存和磨碎食物的功能; 前肠末端有6个贲门瓣伸入中肠。中肠较长且膨大,其肠壁细胞由柱状细胞和再生细胞组成; 肠壁细胞外分别为环肌和纵肌,无胃盲囊,也未观察到围食膜。6根棕红色的马氏管位于中、 后肠分界处。后肠分为不对称的“V”字型回肠、环状结肠、以及膨大透明的直肠, 直肠内壁上有6个交替排列的直肠垫。最后简要讨论了蝎蛉消化道的结构与功能,及其在蝎蛉科昆虫分类中的意义。     

蝗虫消化道结构的比较研究

采用扫描仪分析方法对10种蝗虫消化道形态结构进行了观察比较,发现蝗虫不同类群个体其中肠占消化道总长的比例依进化地位呈现递增趋势,胃盲囊和后肠则呈递减趋势.这种趋势可能是随着蝗虫类群的进化,中肠在消化道所占的比例逐渐增大,对食物的消化吸收能力逐渐增强,与之相应的是胃盲囊呈退化趋势,同时后肠所排泄的残渣逐渐减少,导致蝗虫消化道形态发生适应性变化的结果.     

粉尘螨消化系统的形态学观察

光镜下观察了粉尘螨Dermatophagoides farinae消化系统结构,其组成包括：口前腔、前肠、中肠、后肠、肛门和唾液腺。口前腔由颚体围绕而成;前肠包括一个肌肉的咽和食道,食道从脑中穿过;中肠分为前中肠（包括一对盲肠）和后中肠,中肠的上皮细胞呈现多种形态; 后肠包括相对大的结肠和狭窄的直肠;消化腺为不规则形,位于脑前方。本文阐述了消化道的分支情况、显微结构及细胞形态。     

The functional morphology of the alimentary canal of larval stages of the parasitic copepod Lepeophtheirus salmonis

The functional morphology of the alimentary canal of copepodite and chalimus stages of Lepeophtheirus salmonis (Krøyer, 1837) is described and compared with that found in other copepods studied to date.
The buccal cavity passes into a gut comprising three major regions: foregut (oesophagus), midgut and hindgut. The foregut and hindgut both posscss a cuticular lining whereas the midgut is lined with specialized epithelial cells. The midgut is divided into three recognizable zones, namely anterior midgut caecum, anterior midgut and posterior midgut. Three main types of epithelial cell are recognizable in the midgut: vesicular cells, microvillous cells and basal cells which correspond to the cell types normally described in other parasitic and free-living copepod species.
Digestion is thought to occur in the midgut and be mediated by the epithelial cells that line it. Although several glands appear to discharge into the area of the buccal cavity, none was seen to interface to any other area of the gut. There was no evidence for the involvement of commensal gut bacteria in food digestion.