Department of Biology and Monte L. Bean Museum, Brigham Young University, 4102 LSB, Provo, UT 84602, USA.
Research and Collections Division, The Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, OH 44106, USA.
Proc Biol Sci. 2022 Jul 27;289(1979):20220821. doi: 10.1098/rspb.2022.0821. Epub 2022 Jul 20.
We understand very little about the timing and origins of bioluminescence, particularly as a predator avoidance strategy. Understanding the timing of its origins, however, can help elucidate the evolution of this ecologically important signal. Using fireflies, a prevalent bioluminescent group where bioluminescence primarily functions as aposematic and sexual signals, we explore the origins of this signal in the context of their potential predators. Divergence time estimations were performed using genomic-scale datasets providing a robust estimate for the origin of firefly bioluminescence as both a terrestrial and as an aerial signal. Our results recover the origin of terrestrial beetle bioluminescence at 141.17 (122.63-161.17) Ma and firefly aerial bioluminescence at 133.18 (117.86-152.47) Ma using a large dataset focused on Lampyridae; and terrestrial bioluminescence at 148.03 (130.12-166.80) Ma, with the age of aerial bioluminescence at 104.97 (99.00-120.90) Ma using a complementary Elateroidea dataset. These ages pre-date the origins of all known extant aerial predators (i.e. bats and birds) and support much older terrestrial predators (assassin bugs, frogs, ground beetles, lizards, snakes, hunting spiders and harvestmen) as the drivers of terrestrial bioluminescence in beetles. These ages also support the hypothesis that sexual signalling was probably the original function of this signal in aerial fireflies.
我们对生物发光的时间和起源知之甚少，特别是作为一种逃避捕食者的策略。然而，了解其起源的时间可以帮助阐明这种生态重要信号的进化。利用萤火虫，一个普遍的生物发光群体，生物发光主要作为警戒和性信号，我们在它们潜在的捕食者的背景下探索这种信号的起源。使用基因组规模的数据集进行分歧时间估计，为萤火虫生物发光作为陆地和空中信号的起源提供了可靠的估计。我们的结果通过使用专门针对萤科的大型数据集，将陆地甲虫生物发光的起源恢复为 141.17（122.63-161.17）Ma，而萤火虫空中生物发光的起源为 133.18（117.86-152.47）Ma；使用互补的 Elateroidea 数据集，陆地生物发光的起源为 148.03（130.12-166.80）Ma，空中生物发光的年龄为 104.97（99.00-120.90）Ma。这些年龄早于所有已知现存的空中捕食者（即蝙蝠和鸟类）的起源，并支持更早的陆地捕食者（刺客虫、青蛙、步甲、蜥蜴、蛇、狩猎蜘蛛和盲蛛）是甲虫中陆地生物发光的驱动因素。这些年龄也支持这样的假设，即性信号可能是空中萤火虫中这种信号的原始功能。
