Predation and feeding behavior of corallimorpharian Paracorynactis hoplites (Cnidaria: Anthozoa) on Acanthaster planci in Sogod Bay, Southern Leyte, Philippines

Abstract

Paracorynactis hoplites is one of the natural predators of Acanthaster planci. Hence, this study offers a new knowledge on the predation and feeding behavior of P.hoplites on A. planci in Sogod Bay, Southern Leyte, Philippines. Three different individuals of P.hoplites located in the reef crevices of the fringing reef of Balong-balong, Pintuyan, So. Leyte were fed in situ with adult size A. planci (diameter in cm: 23.75±0.44, mean±SE) in the morning and in the afternoon for the months of Mar 2015 and Jun 2015. The feeding behavior and predation of polyps P. hopliteson A. planci were observed using SCUBA and were video/photo documented for less than 40 minutes using the underwater camera. The polyp P. hoplites extended to reach the prey and pulled A. planci towards the mouth, swallowed and ingested completely. It took about 17.378 to 29.382 min(95% CI) to complete ingestion in the morning and 17.582 to 37.991 min(95% CI) in the afternoon and showed no significant difference using paired t-test (t=0.337; p=0.308). However, the time to complete the ingestion of A. planci by P. hoplites in day one was significantly different from day two (t=0.167; p=0.041) showing that the predator was satiated with its prey but still capable of capturing/killing its prey. Ingestion on day one took 18.603 to 25.862 min(95% CI) and 23.434 to 31.683 min (95% CI) for day two. In the afternoon of the second day, the undigested parts of A. planci composed of spines and calcium carbonate skeleton/test were regurgitated into the sand near the polyp.