Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2013 Aug;199(8):723-33. doi: 10.1007/s00359-013-0831-9. Epub 2013 Jun 9.
The efficiency of acoustic communication depends on the power generated by the sound source, the quality of the environment across which signals propagate, the environmental noise and the sensitivity of the intended receivers. Eupsophus calcaratus, an anuran from the temperate austral forest, communicates by means of an advertisement call of weak intensity in a sound-attenuating environment. To estimate the range over which these frogs communicate effectively, we conducted measurements of sound level and degradation patterns of propagating advertisement calls in the field, and measurements of auditory thresholds to pure tones and to natural calls in laboratory conditions. The results show that E. calcaratus produces weak advertisement calls of about 72 dB sound pressure level (SPL) at 0.25 m from the caller. The signals are affected by attenuation and degradation patterns as they propagate in their native environment, reaching average values of 61 and 51 dB SPL at 1 and 2 m from the sound source, respectively. Midbrain multi-unit recordings show a relatively low auditory sensitivity, with thresholds of about 58 dB SPL for conspecific calls, which are likely to restrict communication to distances shorter than 2 m, a remarkably short range as compared to other anurans.
声通讯的效率取决于声源产生的能量、信号传播的环境质量、环境噪声以及预期接收者的灵敏度。Eupsophus calcaratus 是一种来自温带南方森林的蛙类，它通过在声音衰减环境中传播的弱强度的广告叫声进行交流。为了估计这些青蛙有效传播的范围，我们在野外进行了声音水平和传播广告叫声的衰减模式的测量，以及在实验室条件下对纯音和自然叫声的听觉阈值的测量。结果表明，E. calcaratus 在离发声者 0.25 米处产生约 72dB 声压级（SPL）的微弱广告叫声。信号在其原生环境中传播时会受到衰减和退化模式的影响，在距离声源 1 米和 2 米处分别达到 61dB 和 51dB SPL 的平均水平。中脑多单位记录显示出相对较低的听觉灵敏度，同种叫声的阈值约为 58dB SPL，这可能将通讯限制在 2 米以内的距离，与其他蛙类相比，这是一个非常短的范围。
