Towards a tractable working hypothesis for deimatic displays

Upon being agitated, the mountain katydid, Acripeza reticulata, performs a remarkable defensive display that includes a defensive posture, a display of conspicuous coloration and the release of distasteful, possibly toxic, exudate. From our initial investigations this display appears to be best described as a deimatic display. Deimatic displays are conspicuous behaviours that a prey animal performs when it perceives the threat of an imminent attack by a predator. It can cause a predator to stop, slow or pause its attack, allowing the potential prey to escape ( Edmunds, 1974). In Umbers and Mappes (2015) and Umbers, Lehtonen, and Mappes (2015) we recommended that the definition be extended to include both displays performed early, for example before predators make physical contact, and displays that take place late in the predation sequence, for example after physical attacks by the predator ( Endler, 1991 and Umbers and Mappes, 2015). This forum article provides a valuable opportunity to reflect on the classic definition of deimatic displays, how the definition has been used and how it can be refined.