Senckenberg Publications

P. Bergmann et al.

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Paavo Bergmann Eberhard-Karls University of Tuebingen, Department of Evolutionary Biology of the Invertebrates,
Auf der Morgenstelle 28E, 72076 Tuebingen, Germany;


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Michael Laumann Eberhard-Karls University of Tuebingen, Department of Evolutionary Biology of the Invertebrates,
Auf der Morgenstelle 28E, 72076 Tuebingen, Germany

 
Michael Heethoff Eberhard-Karls University of Tuebingen, Department of Evolutionary Biology of the Invertebrates,
Auf der Morgenstelle 28E, 72076 Tuebingen, Germany
 

 

Ultrastructural aspects of vitellogenesis in Archegozetes longisetosus Aoki, 1965 (Acari, Oribatida, Trhypochthoniidae)


Abstract

We studied the process of vitellogenesis in the oribatid mite Archegozetes longisetosus using light and electron microscopy. Both vitellogenesis and the formation of the first egg shell occur within the meroi of the ovary, starting after detachment from the medulla and completing with ovulation of the egg into the  oviductal  lumen  at  the  ovarial  bulb.  Numerous  microvilli  appear  on  the  surface,  and  abundant endocytotic pits and coated vesicles occur in the peripheral plasma of the oocyte. Accumulation of fatty yolk does not precede accumulation of proteineous yolk. Differentiation of ooplasm and formation of a perivitelline space beneath a continuous follicular epithelium were observed. Vitelline envelope material appears to be uniform. We compare details of vitellogenesis and propose a classification of the ovarian type as panoistic and the vitellogenesis as exogenic in A. longisetosus.

Keywords

mite, oogenesis, yolk, transmission electron microscopy, microvilli, ovary

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