No evidence for conspecific recruitment for cooperative hunting in lionfishPterois miles

Abstract

Lionfish are common piscivores in the Indo-Pacific and invasive in the Caribbean. A fin flaring pattern, involving a rapid undulation of the caudal fin and sequential turning of both pectoral fins, was described in zebra lionfish as a signal to initiate cooperative hunting, and it was hypothesized that such hunting tactics may also exist in other lionfish species and contribute to their successful invasion in the Caribbean. Here, we investigated one of those invasive species, Pterois miles , in its natural range in the Red Sea. We did not observe evidence for cooperative hunting in the field. We complemented field observations with a laboratory experiment aimed at inducing subjects to recruit partners for cooperative hunts, exposing subjects to inaccessible prey in transparent housing as well as to a potential partner. We regularly observed the fin flaring pattern, but importantly, it was not directed at the partner. Thus, rather than being a signal, the fin flaring movement pattern seems to be a swimming mode in a confined environment. Furthermore, the two lionfish did not aggregate at the prey housing, reinforcing the field results that this species in the Red Sea does not depend on cooperation to hunt fish.

No evidence that lionfish Pterois miles coordinate and reciprocate during hunts

“…In summary, our previous [ 13 ] and the current study on P. miles fail to reproduce results on D. zebra [ 16 ], finding no evidence for active recruitment, coordination in time and space, or reciprocity-like alternation in strikes. Thus, lionfish are not in general sophisticated cooperative hunters.…”

“…Furthermore, the stereotyped fin flaring movement pattern was also observed in P. miles , but it was not associated with signalling situations. The authors concluded that fin flaring is linked to manoeuvring in tight places [ 13 ], which would also have applied to the area in front of the partner in the study by Lönnstedt et al . [ 16 ].…”

“…Here, we expand on [ 13 ] and investigate two main questions using laboratory experiments. First, we asked to what degree two P. miles individuals coordinate in space and time when exposed to three alternative hunting locations, i.e.…”

“…Given that complex forms of cooperative hunting are rare and proposed to be linked to specific ecological challenges, one would not expect evidence for complex cooperative hunting in predators like lionfish, which typically hunt alone [11][12][13], though they have been rarely observed to hunt in the presence of conspecific lionfishes [14] or moray eels [15]. However, the hunting behaviour of lionfish Dendrochirus zebra (Scorpaenidae: Pteroinae) described in laboratory experiments [16] was very sophisticated.…”

“…While concerns were raised about the credibility of the published data, as sample sizes were lower than declared [19] and attempts were made to hide this fact with a collage of pictures [20], knowing the hunting strategies of Pterois species may potentially contribute to understanding their invasion success in the Caribbean, and more recently the Mediterranean [21][22][23]. In a first study on Pterois miles in the Red Sea, no evidence was found that individuals seek each other's presence in the field [13]. Furthermore, the stereotyped fin flaring movement pattern was also observed in P. miles, but it was not associated with signalling situations.…”