01828nas a2200181 4500008004100000022001300041245007600054210006900130260001600199300001600215490000700231520124800238100002501486700002901511700002201540700001801562856006601580 2010 eng d a0960982200aAn Aerial-Hawking Bat Uses Stealth Echolocation to Counter Moth Hearing0 aAerialHawking Bat Uses Stealth Echolocation to Counter Moth Hear cJan-09-2010 a1568 - 15720 v203 a

Ears evolved in many nocturnal insects, including some moths, to detect bat echolocation calls and evade capture [1, 2]. Although there is evidence that some bats emit echolocation calls that are inconspicuous to eared moths, it is difficult to determine whether this was an adaptation to moth hearing or originally evolved for a different purpose [2, 3]. Aerial-hawking bats generally emit high-amplitude echolocation calls to maximize detection range [4, 5]. Here we present the first example of an echolocation counterstrategy to overcome prey hearing at the cost of reduced detection distance. We combined comparative bat flight-path tracking and moth neurophysiology with fecal DNA analysis to show that the barbastelle, Barbastella barbastellus, emits calls that are 10 to 100 times lower in amplitude than those of other aerial-hawking bats, remains undetected by moths until close, and captures mainly eared moths. Model calculations demonstrate that only bats emitting such low-amplitude calls hear moth echoes before their calls are conspicuous to moths. This stealth echolocation allows the barbastelle to exploit food resources that are difficult to catch for other aerial-hawking bats emitting calls of greater amplitude.

1 aGoerlitz, Holger, R.1 aHofstede, Hannah, M. ter1 aZeale, Matt, R.K.1 aJones, Gareth uhttp://linkinghub.elsevier.com/retrieve/pii/S096098221000991702082nas a2200229 4500008004100000022001400041245007400055210006900129260001600198300001600214490000700230520136400237653002301601653001601624653003101640653002001671100002901691700002501720700003301745700001901778856005501797 2011 eng d a0028-104200aTympanal mechanics and neural responses in the ears of a noctuid moth0 aTympanal mechanics and neural responses in the ears of a noctuid cJan-12-2011 a1057 - 10610 v983 a

Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement, not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold.

10aauditory threshold10aLepidoptera10amoth auditory biomechanics10aneurophysiology1 aHofstede, Hannah, M. ter1 aGoerlitz, Holger, R.1 aMontealegre-Zapata, Fernando1 aRobert, Daniel uhttp://link.springer.com/10.1007/s00114-011-0851-702397nas a2200181 4500008004100000022001300041245008400054210006900138260001600207300001600223490000700239520181000246100002902056700002302085700002002108700002102128856006602149 2015 eng d a0960982200aEvolution of a Communication System by Sensory Exploitation of Startle Behavior0 aEvolution of a Communication System by Sensory Exploitation of S cJan-12-2015 a3245 - 32520 v253 a

New communication signals can evolve by sensory exploitation if signaling taps into preexisting sensory biases in receivers [1 ;  2]. For mate attraction, signals are typically similar to attractive environmental cues like food [3; 4; 5 ;  6], which amplifies their attractiveness to mates, as opposed to aversive stimuli like predator cues. Female field crickets approach the low-frequency calling song of males, whereas they avoid high-frequency sounds like predatory bat calls [7]. In one group of crickets (Eneopterinae: Lebinthini), however, males produce exceptionally high-frequency calling songs in the range of bat calls [8], a surprising signal in the context of mate attraction. We found that female lebinthines, instead of approaching singing males, produce vibrational responses after male calls, and males track the source of vibrations to find females. We also demonstrate that field cricket species closely related to the Lebinthini show an acoustic startle response to high-frequency sounds that generates substrate vibrations similar to those produced by female lebinthine crickets. Therefore, the startle response is the most likely evolutionary origin of the female lebinthine vibrational signal. In field crickets, the brain receives activity from two auditory interneurons; AN1 tuned to male calling song controls positive phonotaxis, and AN2 tuned to high-frequency bat calls triggers negative phonotaxis [9 ;  10]. In lebinthine crickets, however, we found that auditory ascending neurons are only tuned to high-frequency sounds, and their tuning matches the thresholds for female vibrational signals. Our results demonstrate how sensory exploitation of anti-predator behavior can evolve into a communication system that benefits both senders and receivers.

1 aHofstede, Hannah, M. ter1 aSchöneich, Stefan1 aRobillard, Tony1 aHedwig, Berthold uhttp://linkinghub.elsevier.com/retrieve/pii/S0960982215013585