Role of musculature during defecation in a particle‐feeding arachnid, Archegozetes longisetosus (Acari, Oribatida)
Role of musculature during defecation in a particle‐feeding arachnid, Archegozetes longisetosus (Acari, Oribatida)
复制标题
肌肉组织在以颗粒为食的蜘蛛纲动物Archegozetes longisetosus（螨虫、Oribatida）排便过程中的作用
作者：
M. Heethoff;R. A. Norton
大多数现存的螯肢动物的特征是外部消化和摄取流质食物。包括海洋分类群，大多数Opiliones，和螨类Opilioacarida（寄生虫目）和Sarcoptiformes（蜱螨目），它们摄取颗粒食物。这导致了不同的生理和形态适应食品加工，包括生产和挤出固体粪便颗粒，这是相当大的疥螨。很少有研究调查了如此大的粪便颗粒的排便，现有的信息是矛盾的。我们使用的非侵入性显微镜技术和体内检查相结合，以调查复杂的功能形态的肛门区的甲螨Archegozetes longisetosus青木。肛门的打开至少是由间接的肌肉作用引起的，通过背腹肌（dvm）的作用，血淋巴压力增加。粪粒的排出是由直肠前肌领完成的，肛门完全打开，粪粒的压力可能导致板的旋转和弯曲。这些动作的连续性由许多观察结果证明，其中肛门仅部分打开;这些伴随着dmv收缩，但颗粒未被挤出。所有直接连接到肛门和肛区的肌肉都有助于保持肛门闭合;它们是正常活动所需的流体静力的拮抗剂。根据文献，在其他颗粒摄食螯合动物中没有观察到排便肌肉组织的明显相似性，但大多数肌肉可以与更特化的甲螨同源。肛门外肌的功能在幼螨科（Euphthiracaridae）和短翅目（Brachypylina）中均已改变，以协助提供一般血淋巴压力。J. Morphol.，2009.© 2008 Wiley利斯公司
Most extant Chelicerata are characterized by external digestion and the ingestion of fluid food. Exceptions include the marine taxa, most Opiliones, and the mite groups Opilioacarida (Parasitiformes) and Sarcoptiformes (Acariformes), which ingest particulate food. This leads to different physiological and morphological adaptations for food processing, including the production and extrusion of solid fecal pellets, which are rather large in sarcoptiform mites. Few studies have investigated the defecation of such large fecal pellets, and available information is contradictory. We use a combination of non invasive microscopical techniques and in vivo examination to investigate the complex functional morphology of the anal region of the oribatid mite Archegozetes longisetosus Aoki. The opening of the anus is at least initiated by indirect muscular action via an increase of hemolymph pressure, through the action of dorsoventral muscles (dvm). Extrusion of the fecal pellet is accomplished by the prerectal muscle collar, with full opening of the anus and rotation and bowing of the plates probably resulting from pressure of the pellet. The sequential nature of these actions was demonstrated by many observations in which the anus opened only partially; these were concomitant with dmv contraction but pellets were not being extruded. All muscles directly connected to the anal and adanal regions assist in keeping the anus closed; they are antagonists to hydrostatic forces that are necessary for normal activity. Based on the literature, no obvious similarities were noted with defecation musculature in other particle‐feeding chelicerates, but most muscles can be homologized with those of more specialized oribatid mites. The function of the outer anal muscles has been modified in both Euphthiracaridae and Brachypylina to assist in providing general hemolymph pressure. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.