Tobias Joseph A, Seddon Nathalie
Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
Curr Biol. 2009 Apr 14;19(7):577-82. doi: 10.1016/j.cub.2009.02.036. Epub 2009 Mar 12.
Signal evolution in social animals has produced a wide variety of communal displays, many of them remarkable feats of complex coordination. The two main explanations for this temporal precision are: (1) it evolves as a cooperative signal of coalition quality or (2) it minimizes signal jamming (i.e., interference of one signal by another). However, support for the first hypothesis is inconclusive, and the role of jamming in communal signaling strategies remains unknown. Here, we use playback experiments to examine how social context influences the structure of duets in a pair-living antbird (Hypocnemis peruviana). The results show that, although resident pairs produced coordinated duets when responding to rival pairs, conflicts of interest caused duet coordination to break down. Specifically, females responded to unpaired sexual rivals by jamming the signals of their own mates, who in turn compensated by adjusting their signals to avoid interference. In demonstrating this interaction, we provide the first evidence that signal jamming occurs between mates and that strategies for reducing jamming can result in increased signal complexity. These findings highlight the importance of jamming avoidance in determining the structure of duets and suggest that conflict between signalers, rather than cooperation alone, may drive the evolution of sophisticated communal displays in social animals.
群居动物的信号演变产生了各种各样的群体展示行为，其中许多都是复杂协调的非凡壮举。对于这种时间精度的两种主要解释是：（1）它作为联盟质量的合作信号而演变，或者（2）它将信号干扰（即一个信号对另一个信号的干扰）降至最低。然而，对第一个假设的支持尚无定论，干扰在群体信号策略中的作用仍然未知。在这里，我们使用回放实验来研究社会环境如何影响成对生活的蚁鸟（秘鲁蚁鸫）二重唱的结构。结果表明，虽然常住配对在回应竞争配对时会产生协调的二重唱，但利益冲突会导致二重唱协调破裂。具体而言，雌性通过干扰自己配偶的信号来回应未配对的性对手，而配偶则通过调整信号来避免干扰作为补偿。在证明这种相互作用时，我们提供了第一个证据，表明配偶之间会发生信号干扰，并且减少干扰的策略可能会导致信号复杂性增加。这些发现突出了避免干扰在决定二重唱结构中的重要性，并表明信号发送者之间的冲突，而不仅仅是合作，可能推动群居动物中复杂群体展示行为的演变。
