Ovariole; Oogenesis; Insect phylogeny; Arixenia esau; Dermaptera

Here we present the results of the histological and EM analyses of oogenesis and ovariole structure/ultrastructure in a representative of Arixeniina, Arixenia esau. We show that the studied species shares several important "ovariolar" characters with derived earwigs (Forficulidae). We believe that this finding reinforces the inclusion of the Arixeniina to the Eudermaptera. Our studies indicate additionally that the vitellogenic and postvitellogenic oocytes of A. esau show interesting features that can be interpreted as the adaptations to viviparity, and consequently epizoic life conditions. Thus, the oogenesis of A. esau exemplifies unique mixture of the characters shared with derived earwigs (Forficulidae) and adaptations to the viviparity. (C) 2012 Elsevier GmbH. All rights reserved.