BEHAVIORAL-RESPONSE TO ULTRASOUND BY THE TIGER BEETLE CICINDELA-MARUTHA DOW COMBINES AERODYNAMIC CHANGES AND SOUND PRODUCTION

Tethered flying tiger beetles, Cicindela marutha, respond to trains of bat-like ultrasonic pulses with a short-latency, multi-component beha vior, The head rolls to one side, the metathoracic legs kick to the op posite side, the elytra swing backwards towards the hindwings and pron ate, the hindwings increase their stroke excursion and freqency, and t he plane of the hindwing motion tilts forward, In addition, the beetle s produce trains of ultrasonic clicks typically containing 100-200 cli cks in response to a 1 s stimulus, The clicks average 85-90 dB SPL at 2 cm, The latencies for hindwing changes and elytra swing in response to stimuli more than 10 dB over threshold are 90-110 ms; the latency t o clicking is 120-150 ms. Neither the head roll nor the leg kick appea rs to be directionalrelative to the sound source. The behavioral respo nse is broadly tuned with greatest sensitivity at 30-60 kHz and mean b ehavioral thresholds of 75-80 dB SPL, Physiological audiograms from th e auditory afferents show substantially greater sensitivity and sharpe r tuning than the behavioral response, which suggests that tiger beetl es may use their hearing in other contexts as well as during flight, T he combination of aerodynamic components and arctiid-moth-like clickin g may provide these insects with a powerful defense against attack by echolocating bats.