A marine organism known for its regenerative traits has shown a rare biological response. Under stress, it can revert from an adult state back to its larval form. This finding adds a new layer to existing research on survival strategies in simple organisms.

A Marine Species With Unusual Traits

The warty comb jelly has long drawn scientific attention. It can regenerate damaged body parts and reproduce at early life stages. In addition, it can merge tissues with other individuals to recover from injury.

However, researchers in 2024 identified a different behaviour. The organism appears capable of reversing its development when exposed to extreme conditions.

This process differs from the well-known case of the immortal jellyfish. That species resets its life cycle as a natural function. By contrast, Mnemiopsis leidyi seems to use reversal as a direct response to stress. Therefore, the process appears adaptive rather than automatic.

An Accidental Observation Led to the Study

The research was published in Proceedings of the National Academy of Sciences. It was led by Joan J. Soto-Angel and Pawel Burkhardt from the University of Bergen.

The study began with an unexpected observation. An adult specimen in a lab tank appeared to disappear. In its place, researchers found a larval form. This incident prompted further investigation under controlled conditions.

Earlier studies had shown that comb jellies shrink when food is limited. However, those studies did not confirm full reversal to a younger stage. This new observation challenged that assumption.

Controlled Experiments Show Reverse Development

To test the phenomenon, researchers studied 65 adult specimens. They withheld food for 15 days and later introduced limited feeding.

As a result, some individuals began to lose adult features. Their lobes, which mark maturity, were gradually reabsorbed. Over time, 13 specimens fully transitioned back to a larval form. Their feeding behaviour also matched that of younger organisms.

In a separate experiment, 15 specimens underwent surgical removal of adult structures. These individuals experienced both physical injury and starvation. Interestingly, six of them reverted within 15 days. This was faster than the six-week timeline seen in others.

Therefore, the findings suggest that higher stress levels may accelerate the reversal process.

Open Questions Remain

Despite these observations, the biological mechanism is still unclear. Researchers have not identified the molecular pathways involved. In addition, it is not known how the organism’s nerve system changes during the transition.

Most importantly, the study raises a broader question. Could similar abilities exist in other species? While no clear evidence exists yet, the findings suggest that such mechanisms may be more common than previously assumed.