Experimental study of six coral associated crab species predation potential on egg capsules of Corallivorous gastropod Drupella cornus

Abstract EN

The muricid Drupella cornus feed exclusively on coral colonies and their population outbreaks cause significant coral mortality.

Females of D.

cornus are laying egg capsules on available hard substrata over the year and with peaks during May-July and October-January in the Jeddah coast, Red Sea.

This study was designed to investigate the predation potential of six coral associated species of crabs on the egg capsules of D.

cornus.

Egg capsules of D.

cornus were provided to the six coral associated crab species in experimental exclusion under laboratory conditions for 48 hours to determine their predation potential.

The predation rates on egg capsules varied according to the crab species.

Highest predation rate was recorded for Cyclodius nitidus where 90% (±14.14,n=2)of provided egg capsules were consumed within 48 hrs.

In comparison, only 5% (±7.1, n=2) of the provided egg capsules were consumed by the species Trapezia digitalis.

In the case of Trapezia bidentata, damaged capsules were noticed, with mean of 30% (±14.14, n=2) of the total number of provided capsules, but none of the damaged capsules was eaten.Regarding the three other crab species, Trapezia cymodoce, C ym o melanodactylus and Pseudoliomera speciosa, there was no evidence or signs of predation or even attacks on the egg capsules of D.

cornus.

The results indicated that the crab species C.

nitidus possesses high predation potential on the egg capsules of D.

cornus, therefore the species could be good control labelagent against D.

cornus outbreak.