The occurrence and dynamics of clutch loss and filial cannibalism in two Caribbean damselfishes

Abstract

Field populations of two Caribbean damselfishes. Stegastes dorsopunicans (Poey) and Microspathodon chrysurus (Cuvier), were monitored for 7 months to determine if complete clutch cannibalism by paternal males occurs and to quantify what types of clutches were most vulnerable to cannibalism by the parent. In both species, filial cannibalism was confirmed by both direct observations and analysis of gut contents in guarding males whose clutches had disappeared prematurely. Smaller younger clutches were more likely to be eaten by the parental male in both species. Both species have broad spawning peaks within a lunar month, with males obtaining multiple clutches in a month. In M. chrysurus, there were temporal fluctuations in the magnitude of cannibalism, with higher proportions of clutches disappearing prematurely during months of lower egg production, especially for the last clutch a male received in the reproductive cycle. In S. dorsopunicans, females appeared to prefer to mate with males with early stage eggs while in M. chrysurus males with late-stage eggs were more likely to receive additional clutches. In general, these results support hypotheses for the adaptive significance of filial cannibalism in paternal care species. These data suggest that complete clutch cannibalism is a common phenomenon in fishes that guard demersal eggs and, because some clutches are predictably more vulnerable to filial cannibalism, the occurrence of filial cannibalism can exert a selective influence on female reproductive tactics.