Ultrasound-triggered, flight-gated evasive maneuvers in the praying mantis Parasphendale agrionina. I. Free flight.

Free-flying male praying mantises Parasphendale agrionina (Gerst.) perform evasive maneuvers when stimulated by ultrasound and when attacked by hunting, echolocating bats. They do not, however, respond in any way when standing on a substratum. The maneuvers are graded in intensity with distance from the sound source: far from the source they are simple turns, whereas close to the source they are steep diving turns or spirals. The maneuvers are made under power, and the male's velocity doubles to almost 4 m s-1 by the end of a steep dive. The mantis does not show any directional preference. The behavioral threshold of 64 dB SPL and minimum latency to course change of 125 ms indicate that these mantises should have adequate time to evade bats using calls of greater than 85-90 dB SPL (at 10 cm). In field experiments with wild, hunting bats, P. agrionina successfully evaded capture in all five attacks to which they responded with evasive maneuvers. Out of three attacks on P. aeruginosa and three on a normally non-responding mantis, Miomantis paykullii Stål, in which there were no evasive maneuvers, the mantis was captured in five cases.