Polyp bailout and reattachment of the abundant Caribbean octocoral Eunicea flexuosa

Abstract

Anthozoans exhibit great plasticity in their responses to stressful conditions, including decreasing individual size, detaching from the substratum and relocating, and releasing endosymbiotic microalgae. Another response to stress used by some colonial anthozoans is polyp bailout, in which the coenenchyme breaks down and individual polyps detach from the colony. We observed polyp bailout in the common Caribbean gorgonian Eunicea flexuosa after eight hours of aerial exposure. After nine days, 28% of bailed-out polyps reattached, although none opened to resume feeding. Polyp bailout is a costly and high-risk escape response, but reattachment indicates that this can be a genet-saving behavior in cases where whole-colony mortality is likely. While it has been described in several species of scleractinians and two octocorals, we still do not know how widespread this behavior is in anthozoans.