DEVELOPPEMENT ET REPRODUCTION DE PLEURODELES (AMPHIBIENS URODELES) ECLOS A BORD DE LA STATION SPATIALE MIR * DEVELOPMENT AND REPRODUCTION OF SALAMANDERS (URODELE AMPHIBIAN) HATCHED ONBOARD THE MIR SPACE STATION*

The FERTILE experiment was twice performed onboard the MIR space station during the French Cassiopee and Pegase space missions. The aim of the study was to analyze microgravity effects on the fertilization and embryonic development, and then to study the further development on ground in the urodele amphibian Pleurodeles waltl. For this experiment, a spatial instrument was developed by the CNES and used to rear numerous eggs, embryos and the adults on trays in μG conditions, and several eggs and embryos on a 1G-rotating centrifuge. Numerous embryos were fixed during the flight. Some embryos were kept alive after landing. The young larvae with normal morphology and behavior hatched in microgravity as control animals on earth. Recovered on ground at post-hatching stage, young larvae reared at room temperature underwent metamorphosis and became mature without obvious abnormalities. The rate of development and morphology were analogous in these animals and in ground controls reared during a similar annual period. Analysis of offspring was performed. Born-in-space males were firstly mated with groundcontrol females, and then with born-in-space females. The mating gave progenies that normally developed. Depending on the techniques used and on the limits of the analyses, the works clearly demonstrated that these amphibian embryos born in space are able to live and reproduce after return on earth.