Department of Biology, University of Florida, Gainesville, FL 32611, USA.
McGuire Center for Lepidoptera and Biodiversity, Florida museum of Natural History, University of Florida, Gainesville, FL 32611, USA.
Biol Lett. 2023 Feb;19(2):20220428. doi: 10.1098/rsbl.2022.0428. Epub 2023 Feb 1.
Traits are often caught in a dynamic tension of countervailing evolutionary pressures. Trade-offs can be imposed by predators evolutionarily curtailing the conspicuousness of a sexually selected trait, or acting in opposition to another natural selection pressure, for instance, a different predator with a divergent hunting strategy. Some moon moths (Saturniidae) have long hindwing tails that thwart echolocating bat attacks at night, allowing the moth to escape. These long tails may come at a cost, however, if they make the moth's roosting form more conspicuous to visually foraging predators during the day. To test this potential trade-off, we offered wild-caught Carolina wrens () pastry dough models with real wings that were either intact or had tails experimentally removed. We video recorded wrens foraging on models and found that moth models with tails did not experience increased detection and attack by birds. Thus, this elaborate trait, while obvious to human observers, does not seem to come at a cost of increased avian predator attention. The evolution of long hindwing tails, likely driven by echolocating predators at night, does not seem to be limited by opposing diurnal constraints. This study demonstrates the importance of testing presumed trade-offs and provides hypotheses for future testing.
特征通常处于相互制衡的进化压力的动态紧张之中。权衡可能是由捕食者施加的，捕食者通过进化来削弱性选择特征的显著性，或者与另一种自然选择压力相对立，例如具有不同狩猎策略的另一种捕食者。一些月蛾（Saturniidae）具有长长的后翅尾巴，可以在夜间挫败回声定位蝙蝠的攻击，使飞蛾得以逃脱。然而，如果这些长尾使飞蛾在白天的栖木形式对视觉觅食的捕食者更加显眼，那么它们可能会付出代价。为了检验这种潜在的权衡，我们为野生捕获的卡罗来纳嘲鸫（）提供了带有真实翅膀的糕点面团模型，这些翅膀要么完好无损，要么经过实验切除了尾巴。我们对嘲鸫在模型上觅食进行了视频记录，发现带有尾巴的飞蛾模型并没有增加鸟类捕食者的发现和攻击。因此，这种复杂的特征虽然对人类观察者来说很明显，但似乎并没有增加鸟类捕食者的注意。长后翅尾巴的进化可能是由夜间回声定位的捕食者驱动的，而不会受到白天的限制。这项研究表明了检验假定权衡的重要性，并为未来的检验提供了假设。
