The ability to localize communication signals plays a fundamental role in social interactions. For signal localization to take place, the sensory system of the receiver must extract information about distance and direction to the sender from physical characteristics of the signal. In many sensory systems, information from multiple peripheral receptors must be integrated by central sensory pathways to determine the sender location. Here, we asked whether evolutionary divergence in the electrosensory and visual systems of mormyrid fish is associated with signal localization behavior. In mormyrids, differences in the distribution of electroreceptors on the surface of the skin are associated with differences in the midbrain exterolateral nucleus (EL). Species with electroreceptors clustered in three rosettes on both sides of the head have a small and undifferentiated EL. In contrast, EL is enlarged and subdivided into anterior (ELa) and posterior (ELp) regions in species that have electroreceptors broadly -distributed throughout the body. Interestingly, species with EL and clustered electroreceptors also have larger visual systems and higher visual acuity than species with ELa/ELp and broadly distributed electroreceptors. Species with broadly distributed electroreceptors and ELa/ELp approached a simulated conspecific by following the curved electric field lines generated by the electrosensory stimulus. In contrast, a species with small EL and clustered electroreceptors, but an enlarged visual system, followed shorter and straighter paths to the stimulus source. In the central electrosensory system, evoked field potentials in response to stimuli delivered from the left versus the right differed more in EL than in ELa/ELp. Our results suggest that signal localization behavior is associated with differences in sensory specializations. We propose that the distribution of electroreceptors on the body affects the ability of individuals to align parallel to electric field lines and maintain such alignment while approaching the signal source. The spatial resolution of sensory information relayed from the periphery to the midbrain in species with clustered electroreceptors may allow for gross, but not fine, processing of sender location. Furthermore, visual information may play an important role in localizing signaling individuals in species with small EL and clustered electroreceptors. In line with previous studies, we suggest that the physiological and behavioral differences associated with signal localization reflect adaptations to different habitats and social environments.

中文翻译：

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Mormyrid鱼的感官专长与电信号定位行为的物种差异相关。

定位通讯信号的能力在社交互动中起着根本性的作用。为了进行信号定位，接收器的传感系统必须从信号的物理特性中提取有关到发送器的距离和方向的信息。在许多传感系统中，来自多个外围受体的信息必须通过中央传感路径进行整合，以确定发送者的位置。在这里，我们问到mormyrid鱼的电感应和视觉系统中的进化差异是否与信号定位行为有关。在mormyrids中，皮肤表面电感受器分布的差异与中脑外侧核（EL）的差异有关。带有在两个头部的三个玫瑰丛中聚集的电感受器的物种具有小的且未分化的EL。相反，在具有广泛分布于全身的电感受器的物种中，EL被扩大并细分为前（ELa）和后（ELp）区域。有趣的是，与具有ELa / ELp和广泛分布的电子受体的物种相比，具有EL和簇状电子受体的物种还具有更大的视觉系统和更高的视敏度。带有广泛分布的电感受器和ELa / ELp的物种通过遵循由电感应刺激产生的弯曲电场线来接近模拟的同种。相反，具有较小EL和成簇电感受器，但视觉系统扩大的物种，沿着较短且较直的路径到达刺激源。在中央电传感系统中，响应于从左向右传递的刺激而诱发的场电势在EL中比在ELa / ELp中差异更大。我们的结果表明，信号定位行为与感觉专长的差异有关。我们提出，人体上电感受器的分布会影响个体与电场线平行排列并在接近信号源时保持这种排列的能力。在具有成簇的电感受器的物种中，从外围传递到中脑的感官信息的空间分辨率可能允许对发件人位置进行总体（但不是很好）的处理。此外，视觉信息可能会在具有小EL和簇状电受体的物种中定位信号个体方面发挥重要作用。