title: Embryos of the viviparous dermapteran, Arixenia esau develop sequentially in two compartments: terminal ovarian follicles and the uterus.
abstract: Three main reproductive strategies have been described among insects: most common oviparity, ovoviviparity and viviparity. In the latter strategy, the embryonic development takes place within the body of the mother which provides gas exchange and nutrients for embryos. Here we present the results of histological and EM analyses of the female reproductive system of the viviparous earwig, Arixenia esau, focusing on all the modifications related to the viviparity. We show that in the studied species the embryonic development consists of two "physiological phases" that take place in two clearly disparate compartments, i.e. the terminal ovarian follicle and the uterus. In both compartments the embryos are associated with synthetically active epithelial cells. We suggest that these cells are involved in the nourishment of the embryo. Our results indicate that viviparity in arixeniids is more complex than previously considered. We propose the new term "pseudoplacento-uterotrophic viviparity" for this unique two-phase reproductive strategy.
authors.affiliation: Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology, Jagiellonian University, Krakow, Poland. w.tworzydlo@uj.edu.pl
authors.forename: Waclaw
authors.initials: W
authors.lastname: Tworzydlo
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Kisiel
authors.forename: Szczepan M
authors.initials: SM
authors.lastname: Bilinski
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000648:ultrastructure; D047108:Embryonic Development / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D007313:Insecta / Q000196:embryology*; D008296:Malaysia; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology*; D014599:Uterus / Q000166:cytology / Q000502:physiology*; D052286:Viviparity, Nonmammalian / Q000502:physiology*