Department of Biological Sciences, Lilly Hall, Purdue University, 915 State St, West Lafayette, IN 47907, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2010 Aug;196(8):559-67. doi: 10.1007/s00359-010-0543-3. Epub 2010 Jun 18.
Receiver sensory abilities can be influenced by a number of factors, including habitat, phylogeny and the selective pressure to acquire information about conspecifics or heterospecifics. It has been hypothesized that brood-parasitic brown-headed cowbird (Molothrus ater) females may locate or determine the quality of potential hosts by eavesdropping on their sexual signals. This is expected to produce different sex-specific pressures on the auditory system to detect conspecific and heterospecific acoustic signals. Here, we examined auditory filter shape and efficiency, which influence the ability to resolve spectral and temporal information, in males and females at center frequencies of 2, 3 and 4 kHz. We found that overall, cowbirds had relatively wide filters (lsmean +/- SE: 619.8 +/- 41.6 Hz). Moreover, females had narrower filters (females: 491.4 +/- 66.8, males: 713.8 +/- 67.3 Hz) and greater filter efficiency (females: 59.0 +/- 2.0, males: 69.8 +/- 1.9 dB) than males. Our results suggest that the filters of female cowbirds may allow them to extract spectral information from heterospecific vocalizations. The broader auditory filters of males may reflect limited spectral energy in conspecific vocalizations in this frequency range, and hence, weaker selection for high resolution of frequency in the range of 2-4 kHz.
接收者的感觉能力可能受到多种因素的影响，包括栖息地、系统发育和获取同种或异种信息的选择压力。据推测，巢寄生的褐头牛鹂（Molothrus ater）雌鸟可能通过偷听它们的性信号来定位或确定潜在宿主的质量。这预计会对听觉系统产生不同的性别特异性压力，以检测同种和异种声音信号。在这里，我们检查了在 2、3 和 4 kHz 的中心频率下，雄性和雌性的听觉滤波器形状和效率，这些因素会影响分辨光谱和时间信息的能力。我们发现，总体而言，牛鹂的滤波器相对较宽（lsmean +/- SE：619.8 +/- 41.6 Hz）。此外，雌性的滤波器更窄（雌性：491.4 +/- 66.8，雄性：713.8 +/- 67.3 Hz），滤波器效率更高（雌性：59.0 +/- 2.0，雄性：69.8 +/- 1.9 dB）。我们的研究结果表明，雌性牛鹂的滤波器可能使它们能够从异种声音中提取光谱信息。雄性的较宽听觉滤波器可能反映了在这个频率范围内同种声音的频谱能量有限，因此，在 2-4 kHz 范围内对频率分辨率的选择较弱。
