Feeding and anhydrobiosis in bdelloid rotifers: a preparatory study for an experiment aboard the International Space Station

Here we report the effect of food concentration on the recovery from anhydrobiosis of a bdelloid rotifer Macrotrachela quadricornifera. Cohorts were either starved or fed high or low concentrations of food before being dried and their subsequent recovery rates determined. The rotifers starved for 3 days before anhydrobiosis recovered in significantly higher proportion, and those fed lower food concentration recovered better than those fed higher food concentration. In addition, starvation did not decrease the recovery of other bdelloid species (Philodina roseola and Adineta sp.1) which were either fed or starved before anhydrobiosis. These results suggest that a successful recovery from anhydrobiosis is not dependent on prior resource level supplied to the bdelloids. However, the lack of resources might not be the only factor in a successful recovery from anhydrobiosis. SEM observation of fed M. quadricornifera entering anhydrobiosis showed some food remains in the digestive tract. Thus, we propose that the negative effect of rich food may be due to a purely mechanical effect, maybe interfering with a proper folding of the rotifer body at the onset of anhydrobiosis. This contribution results from studies carried out in preparation for biological experiments scheduled on the International Space Station (ISS).