Chetverikov Philipp E, Desnitskiy Alexey G
Zoological Institute, Russian Academy of Sciences, Universitetskaya Embankment 1, St. Petersburg, Russia, 199034.
Saint-Petersburg State University, Universitetskaya nab., 7/9, St. Petersburg, Russia, 199034.
Exp Appl Acarol. 2016 Jan;68(1):97-111. doi: 10.1007/s10493-015-9982-4. Epub 2015 Nov 3.
The embryonic development of four eriophyoid mite species, Cecidophyopsis ribis, Phytoptus avellanae, Oziella liroi and Loboquintus subsquamatus, has been studied with the use of fluorochrome DAPI and confocal microscopy. The first three nuclear divisions occur on the egg periphery (the groups of 2, 4, and 6 nuclei have been recorded), while the biggest part of yolk remains undivided. After four or five nuclear divisions all nuclei are situated only in one sector of the embryo, while other sectors contain only yolk suggesting possible meroblastic cleavage. Later, the formation of superficial blastoderm takes place. A few large yolk cells are situated inside the embryo. Germ band formation initiates as funnel-like cell invagination and leads to formation of a typical stage with four paired prosomal buds (chelicerae, palps, legs I and II). Each palp contains two lobes (anterior and posterior), the adult subcapitulum is presumably a fusion product of the anterior pair of the lobes. Neither rudiments of legs III and IV, traces of opisthosomal segments nor remnants of the prelarval exuvium under the egg shell were detected. Overall, the pattern of embryonic development in eriophyoids re-emphasizes the peculiarity of this ancient group of miniaturized phytoparasitic animals, and invites researches to pursue a deeper investigation of various fundamental aspects of this aberrant group of Acari. Further studies using various fluorescent dyes and transmission electron microscopy are needed to visualize plasma membranes and clarify the pattern of early cleavage of eriophyoids.
利用荧光染料4',6-二脒基-2-苯基吲哚（DAPI）和共聚焦显微镜，对4种瘿螨（Cecidophyopsis ribis、Phytoptus avellanae、Oziella liroi和Loboquintus subsquamatus）的胚胎发育进行了研究。最初的三次核分裂发生在卵的周边（已记录到2、4和6个细胞核的群体），而大部分卵黄仍未分裂。经过四到五次核分裂后，所有细胞核仅位于胚胎的一个区域，而其他区域仅含有卵黄，这表明可能存在盘状卵裂。之后，形成了表面胚盘。胚胎内部有几个大的卵黄细胞。胚带形成始于漏斗状的细胞内陷，并导致形成一个典型阶段，即具有四对体前部芽体（螯肢、须肢、第一和第二对足）。每个须肢包含两个叶（前部和后部），成虫的假头可能是前部一对叶的融合产物。未检测到第三和第四对足的原基、体后部节段的痕迹或卵壳下幼虫前期蜕皮的残余物。总体而言，瘿螨的胚胎发育模式再次强调了这一古老的小型化植物寄生动物群体的特殊性，并促使研究人员对这一异常的蜱螨类群的各个基本方面进行更深入的研究。需要使用各种荧光染料和透射电子显微镜进行进一步研究，以观察质膜并阐明瘿螨早期卵裂的模式。
