Spiny lobsters elicit avoidance behaviors in corallivorous invertebrates

Corallivory (the consumption of live coral tissue) threatens reef health and can undermine restoration efforts, particularly as coral cover declines. Although predators may suppress corallivore populations through direct consumption, their non-consumptive effects remain poorly understood. We tested whether chemical cues from two spiny lobsters, Panulirus argus and P. guttatus , elicit avoidance responses in two Caribbean corallivores: the snail Coralliophila galea and the fireworm Hermodice carunculata . Using chemical choice trials with lobster-conditioned versus control seawater, we found that fireworms consistently avoided P. argus chemical cues, confirmed by both discrete choice outcomes and time spent data. C. galea , in contrast, showed a significant initial avoidance response to P. argus cues that weakened over the trial, with snails increasingly occupying the mixing zone rather than sustaining their initial position on the control side. By final choice, the pattern of significant differences changed; snails no longer avoided the P. argus side over the control side specifically. Instead, they were significantly more likely to occupy the mixing zone than either the control or the P. argus side, which did not differ significantly from one another. This pattern is consistent with a reduced movement, sheltering in place strategy, but could also reflect habituation or reduced chemosensory responsiveness. In contrast, fireworms made rapid, sustained avoidance responses to P. argus , consistent with active flight behavior. Contrary to our expectation, both corallivores showed weaker or no significant avoidance of the reef-obligate, P. guttatus than of P. argus , possibly reflecting differences in chemical cue composition, concentration, or perceived threat. These results indicate a previously undocumented risk induced behavioral response in which P. argus lobsters may contribute to reduced coral tissue loss without direct predation, although this study measured avoidance behavior rather than corallivory itself. Our findings highlight the importance of invertebrate predators in reef systems and suggest that incorporating predator presence into coral restoration planning merits further investigation as a means of leveraging natural predator–prey dynamics.