Post-attack defensive displays in three praying mantis species

Abstract

Investigating the stimuli that elicit dynamic defensive displays can indicate when throughout the predation sequence prey are likely to perform them. This is crucial to understanding whether these displays function as classic deimatic ‘startle’ displays, facultative aposematism or aid in facilitation of predator learning. We investigated the triggers of defensive display in three different praying mantis species found in eastern Australia; Archimantis latistyla, Hierodula majuscula and Pseudomantis albofimbriata. Dynamic displays in praying mantises have been described as ‘deimatic’ and given the risks inherent in sustaining an attack, especially as mantises are not chemically defended, we predicted that mantises would perform their displays to stimuli that simulate early cues of predation. In a randomised order, we exposed each mantis to five different stimuli simulating a non-specific predator, including tactile and non-tactile stimuli. All species performed their display in response to tactile stimuli however A. latistyla and H. majuscula were more likely to respond than P. albofimbriata. The smallest species, P. albofimbriata, did not readily respond to simulated attacks and was the least likely to perform a display. Our results do not meet the prediction that mantises should respond to stimuli that correspond with early stages of the predation sequence. This raises questions surrounding the utilisation of defensive displays in non-chemically defended prey and contributes to our understanding of predator-prey dynamics during the predation sequence.

Significance statement

Startle displays, or deimatic displays, present some of the most charismatic and well-known examples of animal behaviour and colouration. Particularly in animals such as praying mantises, defensive displays are classically cited examples of anti-predator adaptations. It is generally stated that defensive displays in animals function by startling the predator before they have attacked; however, evidence is accumulating that dynamic displays may function in a number of ways including facilitating predator learning, or facultative aposematism. We found that three species of praying mantises only performed dynamic displays in response to simulated predator attacks. This contrasts with predictions that displays should happen before predator attacks, thus fundamentally challenging our understanding of why these strategies have evolved and how they are utilised in nature. This adds to growing evidence that apparent ‘deimatic displays’ may actually function in other ways such as facilitating predator learning, even in non-chemically defended animals such as praying mantises.