Shatrov Andrey B, Felska Magdalena
Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia, 199034.
Institute of Biology, Department of Invertebrate Systematics and Ecology, Wrocław University of Environmental and Life Sciences, 51-631, Wrocław, Poland.
Exp Appl Acarol. 2017 Aug;72(4):339-365. doi: 10.1007/s10493-017-0172-4. Epub 2017 Aug 29.
Stylostomes (feeding tubes) of Hirsutiella zachvatkini (Schluger) (Trombiculidae), feeding on bank voles [Myodes glareolus (Schreber)], and of Trombidium holosericeum (L.) (Trombidiidae), feeding on larvae of Stenodemini sp. (Heteroptera, Miridae), were studied by TEM methods and on semi-thin sections. The stylostome of H. zachvatkini is a homogeneous structure of low electron density and without strict margins. It extends within the concave host epidermis, undergoing hyperplasia and hyperkeratosis. TEM does not reveal any obvious stratification in the stylostome walls. The cheliceral movable digits are moved apart by 5-6 µm and tightly applied/adhered to the stylostome substance. A local area beneath the open end of the stylostome canal is not empty but contains a nearly homogeneous substrate, which can pass into the central stylostome canal. The latter is mostly free of contents. In contrast to H. zachvatkini, larvae of T. holosericeum form a root-like stylostome chaotically branching within the clear space underneath the host cuticle free of tissue elements. Tubules of the distal stylostome branches become progressively thinner and disappear blindly. As in H. zachvatkini, the stylostome walls of T. holosericeum are devoid of stratification but show moderate to high electron density. The cheliceral movable digits are moved apart by the same distance, as in H. zachvatkini, and tightly applied to the stylostome substance. The lumen of the central canal is either electron lucent, in the distal portions, or filled with a fine granular or homogeneous substrate of low electron density in the proximal portions forming a type of ampoule. This study shows that Trombiculidae and Trombidiidae share similar initial stages of stylostome formation but the resultant stylostome of each family is distinctly different.
研究了以田鼠[棕背䶄（施雷伯）]为食的扎氏赫氏恙螨（施卢格）（恙螨科）和以狭盲蝽属幼虫（半翅目，盲蝽科）为食的全毛绒螨（林奈）（绒螨科）的口针（取食管），采用透射电镜方法并制作半薄切片进行观察。扎氏赫氏恙螨的口针是一种电子密度低且边缘不清晰的均匀结构。它在凹陷的宿主体表皮内延伸，会出现增生和角化过度现象。透射电镜未显示口针壁有任何明显分层。螯肢可动指分开5 - 6微米，并紧密贴合/附着在口针物质上。口针管开口端下方的局部区域并非空的，而是含有一种近乎均匀的基质，该基质可进入中央口针管。中央口针管大多没有内容物。与扎氏赫氏恙螨不同，全毛绒螨幼虫形成一种根状口针，在宿主角质层下方无组织成分的透明空间内杂乱分支。远端口针分支的小管逐渐变细并盲目消失。与扎氏赫氏恙螨一样，全毛绒螨的口针壁没有分层，但显示出中度至高电子密度。螯肢可动指分开的距离与扎氏赫氏恙螨相同，并紧密贴合在口针物质上。中央管的管腔在远端部分电子透明，在近端部分则充满低电子密度的细颗粒或均匀基质，形成一种安瓿样结构。这项研究表明，恙螨科和绒螨科在口针形成的初始阶段有相似之处，但每个科形成的最终口针明显不同。
