Ultrasonic communication and sexual selection in wax moths: female choice based on energy and asynchrony of male signals

Evaluation of amplitude in male song: female waxmoths respond to fortissimo notes

“…Females clearly prefer the higher of two signals differing by as little as 3.5dB in peSPL, which is consistent with previous findingsobtained from a different A. grisella population -that some discrimination even occurs for amplitude differentials of 2dBpeSPL (Jang and Greenfield, 1996). When given male signals in which mean peak amplitude is held constant, females also prefer those signals that exhibit marked fluctuations in peak amplitude over those that remain relatively constant (Fig.3).…”

“…75±6dBpeSPL or 0.1125Pa ±75%, these latter females would have perceived a slower pulsepair rate, as some pulse pairs would have fallen below their threshold. But female A. grisella are expected to reduce their response as pulse-pair rate slows (Jang and Greenfield, 1996;Greig and Greenfield, 2004), indicating that this potential artifact did not confound the result that fluctuating signals are more attractive than the standard. Similarly, we consider the possibility that sensory adaptation to maximum peak amplitudes might have interfered with our tests of female discrimination between standard and fluctuating song.…”

“…We implemented the method of peak equivalents by relating the millivolt output of a continuous 20kHz broadcast, as measured by the condenser ultrasound microphone, to the SPL of this broadcast, as registered by the SPL meter. We then noted the millivolt output of the synthetic song stimulus broadcast as measured by the microphone, and we adjusted the gain on the loudspeaker amplifier until this millivolt output was equivalent to 75dBpeSPL (see Jang and Greenfield, 1996). This peSPL value was roughly equivalent to the song of a male A. grisella 10cm distant, and it was 6-10dB higher than average thresholds observed for female orientation toward male song.…”

“…Playback experiments in which females were attracted to loudspeaker broadcasts of digitized song recordings indicate that phonotaxis thresholds may be as low as 50-60dBSPL [peak amplitude (Brandt et al, 2005) and unpublished data]. Studies of several A. grisella populations showed that females prefer male songs with pulses of greater peak amplitude that are delivered at a faster rhythm, and that include longer asynchrony intervals within the pulse pairs (Jang and Greenfield, 1996;Jang and Greenfield, 1998). A major portion of female evaluation of male song may be based on acoustic power, defined here as the product of mean peak amplitude and pulse pair rate: playback experiments using synthetic signals suggested that females were equally attracted to songs with low peak amplitude pulses delivered at a rapid pulse pair rate and to songs with high peak amplitude pulses delivered at a slow pulse pair rate, with acoustic power held constant in both songs (Greig and Greenfield, 2004).…”

Insect Communication: Concepts, Channels and Contexts

“…자식에 대한 투자의 불 균형은 작동성비(operational sex ratio)의 불균형으로 이어진다 (Gwynne, 1990). 즉 수컷은 자손에 대한 투자가 상대적으로 적 기 때문에 빠른 생식력을 보유하고 있다 (Bateman, 1948 (Jang and Greenfield, 1996). 그렇기 때문에 교미행동 때 뚜렷한 신호를 생산하거나 위험한 행동을 수행해야하는 성 은 주로 수컷이다.…”