No evidence that lionfish Pterois miles coordinate and reciprocate during hunts

Decision rules underlying cooperative hunting can range from very simple to very complex. As lionfishes are naturally solitary hunters, an experimental study documenting active recruitment, coordination and alternating (potentially reciprocal) striking in dwarf lionfish Dendrochirus zebra received major attention. A hypothesis was that sophisticated coordinated hunting may also contribute to the successful invasion of another lionfish species, Pterois miles, in the Caribbean. However, we did not find recruitment signalling in P. miles in parts of its native range, the Red Sea. Here, we expand on these results, testing for coordinated movements and for alternation in strikes. We exposed subject pairs to inaccessible prey in three transparent housings. The two lionfish did not aggregate at the same prey housing or even share larger space units in the presence of prey. In a second experiment, we found that some alternation can be induced if prey items become alternately accessible at two corners, with each lionfish tending to monopolize one corner each. When the movement of prey is slow or even absent, we observed less alternation than expected by chance. In conclusion, P. miles in the Red Sea does not use any coordination to hunt prey.