Reply to the comment by Dalby and Elliott on "Predator classification by the sea pen Ptilosarcus gurneyi (Cnidaria): role of waterborne chemical cues and physical contact with predatory sea stars"

Abstract

The comment of Dalby and Elliott was triggered by a statement we made in a research note to the effect that our study provided the first experimental evidence of predator-classification abilities in cnidarians. Based on an extensive literature search and the appreciation of our manuscript by the reviewers, at the time of publication we believed that this statement was correct. After reviewing the research articles highlighted by Dalby and Elliott, we concur that the statement is incorrect. We discuss some possible reasons why the articles cited by the authors were not found during our literature search, including the use of technical "jargon". In formulating their comment, the authors make several incorrect assumptions, including (i) that our literature search was limited to a single broad review paper and (ii) that we overlooked key information in at least two of the papers we cited. Also, the authors appear to confound predator recognition and predator classification, as some of the articles they cite do not examine predator-classification abilities. Finally, they give the impression that predator-classification abilities are ubiquitous in cnidarians. This appears to be an overstatement, since a number of published studies clearly indicate high variability in the ability of cnidarians to (i) recognize predators and (ii) respond "correctly" according to the relative threat they represent.