BEHAVIORAL-RESPONSES OF A SEX-ROLE REVERSED PIPEFISH TO A GRADIENT OFPERCEIVED PREDATION RISK

Conspicuous behaviors such as courtship and mating often make animals susceptible to predation. When perceiving themselves at an elevated le vel of risk, animals frequently reduce conspicuous behaviors in trade- off for a decrease in probability of being preyed upon. In the present study, we used two experiments to examine the effect of perceived pre dation risk from cod (Gadus morhua) on nonreproductive and reproductiv e behaviors in the sex-role reversed pipefish (Syngnathus typhle). In the first experiment, no differences due to predation risk were detect ed in the nonreproductive behaviors of either males or females. In the second experiment, predation risk had significant effects on reproduc tive behaviors. Pipefish were allowed to court and copulate at four di fferent predation levels. We created predation levels differing in per ceived predation risk by controlling the number of sensory modes throu gh which pipefish could detect the presence of a cod. As predation ris k increased, pipefish copulated and courted less frequently, swam alon e (displayed and searched for conspecifics) less often, and waited lon ger before commencing courtship. These changes in behavior minimized t he amount of time spent above the eelgrass and presumably reduced cons picuousness to visual predators. Pipefish also copulated after a small er amount of courtship as predation risk increased, indicating that th ey may trade information concerning mate quality for a reduction ill p redation risk. No differences were found in any response variable betw een males and females. The role of operational sex ratios and intersex ual competition in determining which sex assumes greater costs in mate acquisition is questioned.