Carlson Bruce A
Department of Biology, Washington University in St Louis, St Louis, MO 63130-4899, USA
J Exp Biol. 2016 Jan;219(Pt 1):31-43. doi: 10.1242/jeb.127720. Epub 2015 Nov 13.
Sensory systems play a key role in social behavior by mediating the detection and analysis of communication signals. In mormyrid fishes, electric signals are processed within a dedicated sensory pathway, providing a unique opportunity to relate sensory biology to social behavior. Evolutionary changes within this pathway led to new perceptual abilities that have been linked to increased rates of signal evolution and species diversification in a lineage called 'clade A'. Previous field observations suggest that clade-A species tend to be solitary and territorial, whereas non-clade-A species tend to be clustered in high densities suggestive of schooling or shoaling. To explore behavioral differences between species in these lineages in greater detail, I studied population densities, social interactions, and electric signaling in two mormyrid species, Gnathonemus victoriae (clade A) and Petrocephalus degeni (non-clade A), from Lwamunda Swamp, Uganda. Petrocephalus degeni was found at higher population densities, but intraspecific diversity in electric signal waveform was greater in G. victoriae. In the laboratory, G. victoriae exhibited strong shelter-seeking behavior and competition for shelter, whereas P. degeni were more likely to abandon shelter in the presence of conspecifics as well as electric mimics of signaling conspecifics. In other words, P. degeni exhibited social affiliation whereas G. victoriae exhibited social competition. Further, P. degeni showed correlated electric signaling behavior whereas G. victoriae showed anti-correlated signaling behavior. These findings extend previous reports of social spacing, territoriality, and habitat preference among mormyrid species, suggesting that evolutionary divergence in electrosensory processing relates to differences in social behavior.
感觉系统通过介导对通信信号的检测和分析，在社会行为中发挥关键作用。在裸臀鱼科鱼类中，电信号在专门的感觉通路中进行处理，这为将感觉生物学与社会行为联系起来提供了独特的机会。该通路内的进化变化导致了新的感知能力，这些能力与一个名为“A类群”的谱系中信号进化速率的增加和物种多样化有关。先前的野外观察表明，A类群物种往往独居且具有领地性，而非A类群物种往往高密度聚集，表明有群游或聚群行为。为了更详细地探索这些谱系中物种之间的行为差异，我研究了来自乌干达卢万达沼泽的两种裸臀鱼科鱼类——维多利亚裸臀鱼（A类群）和德氏新头鱼（非A类群）的种群密度、社会互动和电信号。德氏新头鱼的种群密度更高，但维多利亚裸臀鱼电信号波形的种内多样性更大。在实验室中，维多利亚裸臀鱼表现出强烈的寻求庇护行为和对庇护所的竞争，而德氏新头鱼在有同种个体以及同种信号的电模拟物存在时更有可能放弃庇护所。换句话说，德氏新头鱼表现出社会联系，而维多利亚裸臀鱼表现出社会竞争。此外，德氏新头鱼表现出相关的电信号行为，而维多利亚裸臀鱼表现出反相关的信号行为。这些发现扩展了先前关于裸臀鱼科物种之间社会间距、领地性和栖息地偏好的报道，表明电感觉处理的进化差异与社会行为的差异有关。
