Behavioral deficits in Caenorhabditis elegans raised for six generations under Mars-analog gravity and hypomagnetic fields

Life on Mars will require organisms to endure sustained exposure to reduced gravity and near-absent planetary magnetism, yet little is known about how these factors combine to affect biology across generations. Here, we investigated the effects of Mars-analog gravity and magnetism on neuromuscular, sensory, and morphological function using Caenorhabditis elegans as a model. Animals were reared continuously under ground-based Mars-analog conditions for six generations and assessed at Generations 2, 4, and 6.

We reasoned that developmental disruption could manifest at several levels and assayed body morphology, crawling, swimming, and chemotaxis. Animals remained viable and reproduced in every lineage. Body morphology and crawling behavior remained mostly unaffected whereas chemotaxis was unaffected at first but declined progressively across generations.

Swimming frequency was reduced from the earliest generation assayed and did not worsen thereafter. The two deficits followed different time courses suggesting that they arise from different mechanisms. Neither was reproduced by six generations of passive housing in Earth conditions in the unpowered apparatus.

Because gravity and magnetic field were varied together, these effects cannot be attributed to either factor alone. Our results show that a Mars-analog environment alters behavior in a terrestrial animal without altering its body plan, and that one of these changes was detected only after several generations. Experiments confined to endpoints that do not challenge the organism would have missed the first deficit, and experiments confined to a single generation would have missed the second.

We thank members of the Vidal-Gadea laboratory for technical assistance and discussion. This work was supported by NIAMS awards 1R15AR087731-01 and 2R15AR068583-02 to A.G.V.-G. School of Biological Sciences, Illinois State University, Normal, IL, USA A.

Vidal-Gadea Department of Mathematics, Illinois State University, Normal, IL, USA The authors declare no competing interests. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Below is the link to the electronic supplementary material.