Feeding biology and symbiotic relationships of the corallimorpharian Paracorynactis hoplites (Anthozoa: Hexacorallia)

Polyps of the corallimorpharian Paracorynactis hoplites were studied in coral reefs of the Davao Gulf, the Philippines, between October 2007 and January 2009. Polyps of Paracorynactis hoplites preyed mainly on echinoderms. Predation on seven species of echinoderms was observed in the field (four asteroids, two echinoids and one holothurian); an additional ten species were accepted during feeding trials (four asteroids, four echinoids and two holothurians). The echinoids Diadema setosum, Diadema savignyi and Echinotrix calamaris, and the ophiuriod Ophiomastix sp. were not adversely affected by the polyps. The opisthobranch Phyllidiella pustulosa (Mollusca) was accepted during feeding trials, whereas the gastropod Cypraea tigris was not adversely affected. In a feeding experiment, polyps of Paracorynactis hoplites (maximum diameter 170 mm) completely ingested crown-of-thorns sea stars (Acanthaster planci) of up to 340 mm diameter. The polyps had a mean daily biomass uptake of 24.5 g d-1 when having a single-species asteroid diet. Fishes of several species of families Apogonidae, Gobiidae, Labridae, Pomacentridae, and Pseudochromidae as well as the shrimps (Periclimenes holthuisi, Periclimenes lacerate, Stenopus hispidus and Thor amboinensis) lived near or among the tentacles of the polyps. © National University of Singapore.