'Autotomy' - the ability of an animal to detach a body part to evade predators

Photograph of a specimen of the common European starfish Asterias rubens with a regenerating arm. Starfish shed arms (autotomy) when attacked by predators and then regenerate a new arm to replace the lost arm. Research by scientists at Queen Mary University of London have uncovered the mechanisms of autotomy by identifying a neurohormone that promotes arm loss in starfish. Credit: Professor Maurice Elphick / Queen Mary University of London

Researchers have made a discovery about how starfish manage to survive predatory attacks by shedding their own limbs. The team has identified a neurohormone responsible for triggering this remarkable feat of self-preservation. The study is published in the journal Current Biology.

Autotomy, the ability of an animal to detach a body part to evade predators, is a well-known survival strategy in the animal kingdom.

While lizards shedding their tails are a familiar example, the mechanisms behind this process remain largely intriguing.

Image source: google

Lizards have muscles that fit together like plugs and sockets around their vertebrae, which allows them to easily sever their tails when needed.

Many lizards can grow back their tails. Lizards can regenerate new cartilage in response to skeletal injuries. Scientists have studied the microscopic structures that make this possible, including mushroom-shaped pillars, tiny pores, and micropillars. 

Drawbacks: Losing a tail can have drawbacks for lizards, such as difficulty maneuvering and impressing mates.

Now, scientists have unveiled a key piece of the puzzle. By studying the common European starfish, Asterias rubens, they identified a neurohormone akin to the human satiety hormone, cholecystokinin (CCK), as a regulator of arm detachment.

Furthermore, the scientists propose that when this neurohormone is released in response to stress, such as a predator attack, it stimulates the contraction of a specialized muscle at the base of the starfish's arm, effectively causing it to break off.

Remarkably, starfish possess incredible regenerative abilities, allowing them to grow back lost limbs over time. Understanding the precise mechanisms behind this process could hold significant implications for regenerative medicine and the development of new treatments for limb injuries.

Discovery of a neuropeptide that acts as an autotomy-promoting factor, Current Biology (2024). DOI: 10.1016/j.cub.2024.08.003. www.cell.com/current-biology/f … 0960-9822(24)01079-0