Colonies of P. sibogm are maintained continuously in constant-
flow seawater tanks in our laboratory. Although most
adult animals are offspring of previous laboratory-reared
generations, the populations are periodically augmented
with new animals collected from the cc& reefs of Hawaii.
These stocks are fed by placing heads of locally collected
Porites compressa coral in their tanks. All specimens of P.
sibogae used in this study were taken from the laboratory
colonies.