Oogenesis; Ovary; Germline cysts; Phylogeny; Evolution; Dermaptera Article Outline

We studied the ovary structure and initial stages of oogenesis in 15 representatives of several dermapteran taxa, including the epizoic Arixeniina. In all examined species, the ovaries are meroistic-polytrophic. Our studies indicate that despite a rather unique morphology of the ovarian follicles in the examined species, the processes leading to the formation of the oocyte and nurse cell units are significantly different in basal versus derived taxa. The ovaries of Arixenia esau are composed of 3 short ovarioles attached to a strongly dilated lateral oviduct, ?the uterus?, containing developing embryos. Histological analysis suggests that the origin of the oocyte and nurse cell units in this species follows the pattern described in eudermapterans.