Santos Juan C, Baquero Margarita, Barrio-Amorós César, Coloma Luis A, Erdtmann Luciana K, Lima Albertina P, Cannatella David C
Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 National Evolutionary Synthesis Center, Suite A200, 2024 West Main St., Durham, NC 27705, USA
Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA.
Proc Biol Sci. 2014 Dec 7;281(1796):20141761. doi: 10.1098/rspb.2014.1761.
Multimodal signals facilitate communication with conspecifics during courtship, but they can also alert eavesdropper predators. Hence, signallers face two pressures: enticing partners to mate and avoiding detection by enemies. Undefended organisms with limited escape abilities are expected to minimize predator recognition over mate attraction by limiting or modifying their signalling. Alternatively, organisms with anti-predator mechanisms such as aposematism (i.e. unprofitability signalled by warning cues) might elaborate mating signals as a consequence of reduced predation. We hypothesize that calls diversified in association with aposematism. To test this, we assembled a large acoustic signal database for a diurnal lineage of aposematic and cryptic/non-defended taxa, the poison frogs. First, we showed that aposematic and non-aposematic species share similar extinction rates, and aposematic lineages diversify more and rarely revert to the non-aposematic phenotype. We then characterized mating calls based on morphological (spectral), behavioural/physiological (temporal) and environmental traits. Of these, only spectral and temporal features were associated with aposematism. We propose that with the evolution of anti-predator defences, reduced predation facilitated the diversification of vocal signals, which then became elaborated or showy via sexual selection.
多模态信号在求偶过程中有助于与同种个体进行交流，但它们也可能会提醒窃听的捕食者。因此，信号发送者面临两种压力：吸引伴侣交配和避免被敌人发现。对于逃脱能力有限且没有防御能力的生物来说，预计它们会通过限制或改变信号来尽量减少捕食者的识别，而非吸引配偶。或者，具有反捕食机制（如警戒色，即通过警告信号表明不可食用）的生物可能会由于捕食压力降低而精心设计交配信号。我们假设叫声的多样化与警戒色有关。为了验证这一点，我们为一个昼行性的具有警戒色和隐秘/无防御能力的类群——箭毒蛙，建立了一个大型声学信号数据库。首先，我们发现具有警戒色和不具有警戒色的物种灭绝率相似，且具有警戒色的谱系分化更多，很少会恢复到不具有警戒色的表型。然后，我们根据形态学（频谱）、行为/生理学（时间）和环境特征对交配叫声进行了特征描述。其中，只有频谱和时间特征与警戒色有关。我们认为，随着反捕食防御机制的进化，捕食压力的降低促进了声音信号的多样化，这些信号随后通过性选择变得更加复杂或显眼。
