Krobath I, Römer H, Hartbauer M
Institute of Zoology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
Behav Ecol Sociobiol. 2017;71(11):164. doi: 10.1007/s00265-017-2381-6. Epub 2017 Oct 24.
Males of a trilling species in the complex produce conspicuous calling songs that consist of two motifs: an amplitude-modulated motif with alternating loud and soft segments (AM-motif) and a continuous, high-intensity trill. The function of these song motifs for female attraction and competition between males was investigated. We tested the hypothesis that males modify their signaling behavior depending on the social environment (presence/absence of females or rival males) when they compete for mates. Therefore, we analyzed acoustic signaling of males in three different situations: (1) solo singing, (2) acoustic interaction with another male, and (3) singing in the presence of a female. In addition, the preference of females for these song motifs and further song parameters was studied in two-choice experiments. As expected, females showed a preference for conspicuous and loud song elements, but nevertheless, males increased the proportion of the AM-motif in the presence of a female. In acoustic interactions, males reduced bout duration significantly compared to both other situations. However, song bouts in this situation still overlapped more than expected by chance, which indicates intentionally simultaneous singing. A multivariate statistical analysis revealed that the proportion of the AM-motif and the duration of loud segments within the AM-motif allow a reliable prediction of whether males sing in isolation, compete with another male, or sing in the presence of a female. These results indicate that the AM-motif plays a dominant role especially in close-range courtship and that males are challenged in finding a balance between attracting females and saving energy during repeated acoustic interactions.
Males of acoustic insects often produce conspicuous calling songs that have a dual function in male-male competition and mate attraction. High signal amplitudes and signal rates are associated with high energetic costs for signal production. We would therefore predict that males adjust their signaling behavior according to their perception of the social context. Here we studied signal production and mate choice in a katydid, where males switch between loud and soft song segments in a dynamic way. Additionally, we examined the attractiveness of different song elements in female choice tests. Our results show how males of this katydid deal with the conflict of remaining attractive for females and competing with a costly signal with rivals.
该复合体中一个颤音物种的雄性会发出引人注目的求偶鸣叫，其由两个主题组成：一个具有交替的响亮和柔和片段的调幅主题（调幅主题）和一个连续的高强度颤音。研究了这些鸣叫主题在吸引雌性和雄性之间竞争中的作用。我们检验了这样一个假设：当雄性争夺配偶时，它们会根据社会环境（雌性或竞争雄性的存在与否）来改变其信号行为。因此，我们分析了雄性在三种不同情况下的声学信号：（1）独唱，（2）与另一只雄性进行声学互动，以及（3）在雌性面前鸣叫。此外，在二选一实验中研究了雌性对这些鸣叫主题和其他鸣叫参数的偏好。正如预期的那样，雌性表现出对显眼且响亮的鸣叫元素的偏好，但尽管如此，雄性在有雌性在场时会增加调幅主题的比例。在声学互动中，与其他两种情况相比，雄性显著缩短了鸣叫回合的持续时间。然而，这种情况下的鸣叫回合仍然比随机预期的重叠更多，这表明存在故意同时鸣叫的情况。多变量统计分析表明，调幅主题的比例以及调幅主题内响亮片段的持续时间能够可靠地预测雄性是独自鸣叫、与另一只雄性竞争还是在雌性面前鸣叫。这些结果表明，调幅主题尤其在近距离求偶中起主导作用，并且雄性在吸引雌性和在反复的声学互动中节省能量之间找到平衡时面临挑战。
声学昆虫的雄性通常会发出引人注目的求偶鸣叫，这些鸣叫在雄性间竞争和配偶吸引中具有双重功能。高信号幅度和信号速率与信号产生的高能量成本相关。因此，我们预计雄性会根据它们对社会环境的感知来调整其信号行为。在这里，我们研究了一种螽斯中的信号产生和配偶选择，其中雄性以动态方式在响亮和柔和的鸣叫片段之间切换。此外，我们在雌性选择测试中检验了不同鸣叫元素的吸引力。我们的结果展示了这种螽斯的雄性如何应对在对雌性保持吸引力和与竞争对手进行代价高昂的信号竞争之间的冲突。
