Female genitalia, reproductive cycle and sperm storage in Armadillidium vulgare (Crustacea, Isopoda, Oniscidea)

Abstract

Light and electron microscopic studies that we have published in the past have reported many aspects of the reproductive process in Armadillidium vulgare with particular emphasis on the reconstruction of female genitalia. Together this body of work provides an almost complete, albeit fragmented picture of these processes and include many data on sperm storage and sperm translocation. Females of A. vulgare have a pair of cuticular genitalia in the lumen of the oviduct. For insemination, these genitalia can receive the copulatory organs of males formed by the elongated tips of the first two pleon endopods. During transitions between reproductive (parturial) and non-reproductive (normal, non-parturial) moult cycles the genitalia undergo intriguing structural changes resulting in two types of genitalia. Throughout their reproductive lifetime, either type is reconstructed after each moult depending on the reproductive phase of the female. In this review, we integrate the events that occur during a reproductive cycle with particular emphasis on the genitalia reconstruction and sperm storage, and discuss functional aspects of the genitalia. Thereby, we provide a case model that can be useful for further studies on genitalia diversity and female reproductive strategies in terrestrial isopods.

Keywords:

• female genitalia
• reproduction
• spermatozoa
• oviduct
• seminal receptacle
• isopoda

Acknowledgements

The authors thank Dr M. Warburg (Israel) and Dr M. Ueno (Kitasato University, Japan) for critical reading of the manuscript and for the helpful comments.