Rhizocephala members have the ability to manipulate its decapod hosts’ behavior, anatomy, and physiology. The immune system of Rhizocephala and the effect of Rhizocephala infections on immunity of parasitized crabs have not been discussed. This study describes the expressions of several immune-related genes in Polyascus planus (parasitic barnacle)-parasitized Metopograpsus thukuhar and in…