Like all species in the Faviidae family, Platygyra sinensis is a zooxanthellate coral, meaning that it obtains most of its nutrients from symbiotic algae, known as zooxanthellae, which live within its tissues. The zooxanthellae provide the coral with nutrients through photosynthesis, but this restricts corals such as Platygyra sinensis to living in relatively clear, warm, shallow waters where photosynthesis can take place. In return for nutrients, the coral provides the zooxanthellae with a safe, stable environment in which to live (3) (6).
In addition to receiving nutrients in this way, Platygyra sinensis is able to supplement its diet with tiny zooplankton, which it catches using stinging cells on its tentacles. The tentacles of this species are usually only extended for feeding at night, and are retracted during the day (3).
Like other corals, Platygyra sinensis is able to reproduce asexually by a process known as ‘budding’, in which a polyp divides into two or more new polyps. Corals also reproduce sexually, usually by releasing large numbers of eggs and sperm into the water column, where the eggs are fertilised and develop into larvae. The larvae eventually settle onto the substrate and develop into polyps, starting new colonies (3).
Relatively little information is available on reproduction in Platygyra sinensis, but it is reported to have pink eggs and is hermaphroditic, with each polyp producing both eggs and sperm. In the Great Barrier Reef, off the coast of Australia, Platygyra sinensis has been recorded taking part in mass spawning events with other coral species, with most colonies releasing their eggs and sperm over a number of consecutive nights. Spawning in this region has been recorded in spring, between October and November, and usually occurs after a full moon. Platygyra sinensis has been found to spawn around three to four hours after sunset (7).