Octopuses influence den selection by juvenile Caribbean spiny lobster

Abstract

Octopuses are notorious predators of crustaceans, yet knowledge of their interactions with lobsters is largely anecdotal. Whether by preying on juvenile lobsters or by competing with them for dens or bivalve prey, octopuses should influence the den selection and therefore spatial distribution of lobsters. Lobsters are chemosensitive, so if the interaction is strong, they may respond to chemical cues produced by octopuses and avoid dens or areas where octopuses dwell. In mesocosms, juvenile Caribbean spiny lobsters (Panulirus argus) avoided dens emanating octopus chemical signals. Field manipulations of artificial dens at several spatial scales (<0.1 m to 10 m) showed that the distribution of lobsters was significantly influenced by the proximity of octopuses. Lobsters were significantly less likely to inhabit dens within 2 m of an octopus den, but this strong negative effect disappeared when dens were 10 m apart.