Comb jellyfish, scientifically known as Mnemiopsis leidyi, have a unique ability that sets them apart from other sea creatures.
When faced with injury, these small, gelatinous animals can join together with others of their kind to create a single, larger entity. This process goes beyond simple surface-level attachment, as the jellyfish actually merge their nervous systems and digestive tracts.
The discovery of this unusual trait came about through an unexpected observation.
Scientists at the University of Chicago’s Marine Biological Laboratory noticed a comb jellyfish specimen with odd features, including two sensory organs and two rear ends. This led them to wonder if the creature had once been two separate jellyfish that had fused together.
To test their theory, the researchers conducted experiments by partially cutting lobes from different jellyfish and placing them together.
The results were striking:
- 90% of the pairs successfully fused
- Merged jellyfish survived for at least three weeks
- Fusion occurred rapidly, with movement synchronization beginning within an hour
The extent of the fusion was remarkable.
After just one night, the outer layers of tissue appeared seamless, and the nervous systems showed signs of connection. When one side of the fused jellyfish was touched, both sides reacted. This suggests a deep level of integration between the formerly separate organisms.
The digestive systems of the fused jellyfish also worked as one.
In one experiment, researchers fed a fluorescent substance to one side of a merged pair. They observed the glowing particles moving through both halves of the creature, showing that the digestive tracts had joined.
Despite this high degree of fusion, some signs of individuality remained.
For example, waste expulsion was not always synchronized between the two halves. This hints that the merged jellyfish may not become a truly single animal in every respect.
The ability of comb jellyfish to fuse in this way raises many questions:
- How do their nervous systems join together so effectively?
- Why has this survival mechanism evolved?
- What are the limits of this fusion process?
One particularly interesting aspect of this discovery is the jellyfish’s apparent lack of allorecognition.
This is the ability to tell the difference between one’s own cells and those of another organism. In humans and many other animals, allorecognition is crucial for the immune system to function properly.
The absence of this trait in comb jellyfish could have important implications for medical research.
Scientists are keen to study these creatures further to gain insights that could potentially help with:
- Organ transplant procedures
- Immune system therapies
- Regeneration treatments
