A Test of the Function of Juvenile Color Patterns in the Pomacentrid Fish Hypsypops rubicundus (Teleostei: Pomacentridae)

Abstract

Color patterns of juveniles of many fish species differ from those of adult conspecifics. The adaptiveness of such coloration has seldom been studied, despite longstanding interest in the subject. I tested the hypothesis that distinctive juvenile coloration masks species identity, thereby reducing aggression from adults and permitting young fish to occupy areas within adult territories. I measured the responses of adult, territorial garibaldi (Hypsypops rubicundus [Girard]) to naturally colored juveniles and to juveniles altered to resemble adults or heterospecifics when presented live in clear, plastic bags filled with seawater. Preliminary results showed that adults attacked normally colored juveniles more than any other color pattern presented, indicating that juvenile coloration in H. rubicundus does not inherently reduce adult aggression. I discuss the merits and testability of alternative hypotheses for ontogenetic color change in damselfishes.