Science
Flatworms may grow back or lay many eggs. This was demonstrated by a study in collaboration with Tyrolean researchers. Apparently, some species had to choose one of the two characteristics during development.
October 23, 2023 7:20 am
Online since today, 7:20 am
Flatworms, also known as planarians, can regenerate entire animals from body parts. However, the ability to do this varies greatly between individual species. The species Schmidtea mediterranea can regenerate a complete animal from almost any part of the body. As part of the study, planarian species from around the world were examined.
Bernhard Egger/Fabian Oswald The native planarian Crenobia alpina, found in alpine streams
The University of Innsbruck contributed specimens from its collection
The study was led by Jochen Rink and Miquel Vila-Farre from the Max Planck Institute for Multidisciplinary Natural Sciences in Göttingen, where more than 40 species of planarians were examined. The University of Innsbruck also contributed five species from its extensive planarian collection. Bernhard Egger and Alexandra Grosbusch from the Institute of Zoology at the University of Innsbruck also examined two species of close relatives of planarians in which regeneration is only weak. These animals can no longer recover from a certain part of the body.
The animals were suddenly able to restore their heads
The study showed that there is a strong link between a specific signaling pathway and the ability to regenerate. In biology, a signaling pathway is a sequence of chemical processes through which an organism reacts to external stimuli. If researchers inhibited the production of a component of the signaling pathway, namely the beta-catenin1 protein, animals with poor regenerative capacity would suddenly be able to restore their heads.
Evolutionary exchange
However, beta-catenin1 not only blocks head regeneration but also promotes bud formation. In the case of some planarians, the ability to regenerate the head competed with the ability to lay more eggs, explains Bernhard Egger.
The researcher therefore raises the hypothesis that losing one’s head is a rare event and that the capacity for regeneration is, therefore, treated as a “nice to have”, that is, neutral, in evolution. “In a sense, it’s a kind of evolutionary exchange to be able to lay more eggs,” says Egger