“Nobody expected this,” said Gerhard Scholtz of the Humboldt University in Berlin, lead author of the study published in the American scientific journal PNAS. “We were the first to show that this is possible,” he added.
Many different types of arthropods, such as centipedes, spiders, and other insects, are known to be able to regrow limbs after loss.
“Crabs can even automatically shed their limbs in the event of an attack,” Scholtz said, explaining that “they replace it with a new limb.”
What the researchers discovered from their experiments with the tiny eight-legged sea spiders is that they can regenerate other body parts besides limbs.
For the study, they amputated different hind limbs and hindquarters from 23 juvenile and adult sea spiders and observed the results. They did not see regeneration of body parts in the adult sea spiders, but some of them were still alive two years later.
Juvenile specimens, on the other hand, underwent complete or near-complete regeneration of missing body parts, including the hindgut, anus, musculature, and parts of the genitalia.
In the long term, 90% of the sea spiders survived and 16 juveniles subsequently regenerated at least once. Rear regrowth was observed in 14 of the young spiders, while none of the adult specimens regenerated.
Regenerative abilities vary throughout the animal kingdom. Worms, for example, can regenerate their body from just a few cells. Vertebrates, including humans, have virtually no ability to regenerate, with a few exceptions, such as lizards, which can regrow their tails.
According to Scholtz, these findings open up new avenues for research in the field. “You can test a lot of different species,” he said, which could allow comparisons between regeneration mechanisms.
“Ultimately, perhaps the mechanisms that we discover in arthropods will help us in medical treatments after the loss of a limb, a finger, in humans,” Scholtz said. “This is always the hope.”