Grapevine

After injury, one species of comb jelly can fuse to become one

Jokura and colleagues made the observation after keeping a population of the comb jellies in a seawater tank in the lab. They noticed an unusually large individual that seemed to have two backends and two sensory structures known as apical organs instead of one. They wondered if this unusual individual arose from the fusion of two injured jellies.

To find out, they removed partial lobes from other individuals and placed them close together in pairs. It turned out that, nine out of 10 times, it worked. The injured individuals became one, surviving for at least three weeks.

Further study showed that after a single night, the two original individuals seamlessly became one with no apparent separation between them. When the researchers poked at one lobe, the whole fused body reacted with a prominent startle response, suggesting that their nervous systems were also fully fused.