Abstract
The sex ratio of water mite Unionicola anodontae fluctuated around 50% with biased value to the females. The female reproductive system consists of two different functional parts. The first part is designed for production of ova, formation of egg chorion and releasing of ova and embryos to the exterior. The second part functions in mating, sperm storage and sperm transport.The male reproductive system consists of paired testes, two vasa deferentia, an accessory gland, short ejaculatory duct and copulatory organ. Fertilization occurs within the ovary.The zygote nucleus undergoes superficial cleavage, giving rise to a blastula. Gastrulation starts with the formation of the germ band (disc). The larvae develop into nymphs before attaining the Juvenile stage.