The ctenophore Mnemiopsis leidyi is able to reverse develop under unfavorable conditions.

What is it about?

Aging is a one-way, irreversible path for a great majority of animals. So far, the ability to morphologically rejuvenate by reverse development was only known for a few species, including true jellyfish, a coral and a tape worm. We found that the comb jelly Mnemiopsis leidyi is able to transform into an earlier life cycle stage after physical injury or a period of prolonged starvation. By following morphometric changes and individual trajectories over time, we documented how these animals progressively lost their typical adult morphology and anatomical structures (i.e. lobes and auricles) and regained larval specific features (i.e. the tentacles) and behavior. These findings suggest that reverse development may be more widespread in the tree of life than previously thought and that M. leidyi could be a good animal model for studying aging and rejuvenation.

Featured Image

Photo by Jonathan Diemel on Unsplash

Photo by Jonathan Diemel on Unsplash

Why is it important?

This study reveals the first documented case of reverse development in ctenophores. The occurrence of this peculiar trait in a lineage that originated prior to cnidarians helps illuminating central aspects of life cycle plasticity and evolution in early animals. On the other hand, larval and adult stages of Mnemiopsis leidyi capture prey in completely different ways, occupying and exploiting different ecological niches. Thus, the ability to rejuvenate in harsh conditions also provides further research opportunities for ecological studies aiming to explain M. leidyi’s high invasive success.

Perspectives