Establishment of a rearing system of the extremotolerant tardigrade ; A New model animal for astrobiology

Horikawa, Daiki*; Kunieda, Takekazu*; Abe, Wataru*; Watanabe, Masahiko*; Nakahara, Yuichi*; Yukuhiro, Fumiko*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; Katagiri, Chihiro*; Kobayashi, Yasuhiko; Higashi, Seigo*; Okuda, Takashi*

We report the successful rearing of the herbivorous tardigrade, , by supplying the green alga as food. The life span was 35 d, deposited eggs required 5.7 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90C and -196C and exposure to 99.8% acetonitrile or irradiation with 4000 Gy He ions. Based on their life history traits and tolerance to extreme stresses, might be a suitable model for astrobiological studies of multicellular organisms.