Injection of Love Hormone in Starfish causes its stomach to evert out of its mouth

An interesting study published by Queen Mary University of London reports the release of love hormone in human brain, which also has an effect among starfish, enabling them to turn their stomach inside out to feed.

The hormone, Oxytocin, commonly known as ‘love hormone’ plays a pivotal role in sexual reproduction among humans and mammals, including nematode worms. However, the hormone is especially potent in European starfish (Asterias rubens) for the purpose of feeding.

The new study concludes that the oxytocin-type molecules control the feeding behavior of the crown of thorns starfish (Acanthaster planci) and it also had an impact on the nervous system of animals for over half-a-billion years. Furthermore, the crown of thorns starfish feeds on coral, which is causing a devastating impact on the functioning of the Australian Great Barrier Reef.

According to experts, the effects of feeding were known to be different among various animal types, for instance among starfish, the oxytocin molecule played a much crucial role in normal feeding than among mice, where oxytocin inhibited feeding behavior.

“Our study has provided important new evidence that oxytocin-type molecules are important and ancient regulators of feeding in animals. So oxytocin is much more than a ‘love hormone’ – perhaps especially for animals like starfish that don’t fall in love!” commented Professor Maurice Elphick, lead author of the Queen Mary University of London.

According to Odekunle, if the love hormone played an important role in the feeding behavior of the crown of thorns starfish, the study may also lay groundwork for the development of chemical methods which could control their appetite for coral.

For the investigation, researchers injected the hormones into starfish. Within a couple of minutes, it was observed the starfish began bending arms and adopted a ‘humped’ position, similar to the posture when they were feeding. Additionally, it also caused the starfish to evert their stomach out of their mouth.

This was attributed as an interesting combination of effects, as the starfish usually fed by climbing on top of the prey and adopted a rigid humped posture, in order to capacitate the pulling power of tiny tube feet on the underside of each arm and pull apart the prey by two valves.

“What is fascinating is that injecting the hormone in starfish induces what is known as fictive feeding. The starfish are behaving as if they are feeding on a mussel or an oyster but no mussel or oyster is there to be eaten,” reported Professor Elphick.

In conclusion, experts found that the hormone was so powerful, it made the starfish 2-3 times slower at righting themselves when they flipped over. This has been considered as a significant defense behavior as the creatures can be upturned by waves.

Furthermore, it was also found that the hormone and its receptor were found in several parts of the body of the starfish, including the central nervous system and in the stomach. This discovery was considered as consistent with the striking effects of the oxytocin-like molecule on starfish behaviour.

The findings which play a crucial role in controlling the feeding behavior of the crown of thorns starfish, were published in the journal BMC Biology.