CORALS ARE MORE COLLABORATIVE AND FEROCIOUS THAN WE THOUGH
Corals are sessile animals, they feed on zooplankton. Coral polyps come out of their skeletons to feed, stretching their stinging tentacles to capture floating preys, which will then be digested in their stomachs. But a recent observation of a rare behavior is changing our mind about how coral catch and consume large animals. Marine biologists noticed in waters around italian island how orange coral (Astroides calycularis) catches and consumes mauve stinger (Pelagia noctiluca), a large jellyfish, potentially stinging.
The Orange Coral is endemic to the Mediterranean Sea where it can be reef forming, where colonies frequently occur in dense aggregations. High water movement promotes massive colony shapes, leaving little space for the settlement of other benthic organisms. Polyps coral form a “wall of mouths, where they coordinates to feed on large jellyfish. Researchers saw 20 mauve stinger eaten by corals in 2010, 2014, and 2017, during field survey campaigns carried out in different localities of the Mediterranean Sea.
- Gifs of a mauve stinger being eaten by a “wall of mouths”.
Corals and jellyfish are related, both belonging to the cnidarians, a group of soft body animals with stinging tentacles surrounding a single mouth.
This is not the fist time a coral has been spotted consuming a jellyfish, medusivory have been described several times. In 2009, researchers described a mushroom corals slurping up moon jellies in the Gulf of Aqaba (Red Sea), also, in 2014 Indonesian anemones were discovered feeding on several kinds of swimming jellies.
Photo: Musco et al., 2018.
Reference: Musco et al., 2018. Protocooperation among small polyps allows the coral Astroides calycularis to prey on large jellyfish. The Scientific Naturalist.
Full video here.
[Image description: a group of yellow polyps of coral stick to a large single jellyfish]
