Data from: Vestigial singing behaviour persists after the evolutionary loss of song in crickets

The evolutionary loss of sexual traits is widely predicted. Because sexual signals can arise from the coupling of specialised motor activity with morphological structures, disruption to a single component could lead to overall loss of function. Opportunities to observe this process and characterise any remaining signal components are rare, but could provide insight into the mechanisms, indirect costs, and evolutionary consequences of signal loss. We investigated the recent evolutionary loss of a long-range acoustic sexual signal in the Hawaiian field cricket Teleogryllus oceanicus. Flatwing males carry mutations that remove sound-producing wing structures, eliminating all acoustic signalling and affording protection against an acoustically-orientating parasitoid fly. We show that flatwing males produce wing movement patterns indistinguishable from those that generate sonorous calling song in normal-wing males. Evolutionary song loss caused by the disappearance of structural components of the sound-producing apparatus has left behind the energetically-costly motor behaviour underlying normal singing. These results provide a rare example of a vestigial behaviour and raise the possibility that such traits could be co-opted for novel functions.

性征的演化丢失是学界广泛预测的演化现象。由于性信号可源于特化运动活动与形态结构的耦合，单一组成部分的破坏便可能导致整体功能丧失。观察该过程并表征任何残留信号组分的研究机会十分稀缺，但此类工作可帮助我们深入解析信号丢失的机制、间接成本及其演化后果。我们针对夏威夷田野蟋蟀（Teleogryllus oceanicus）的长距离声学性信号的近期演化丢失展开了研究。平翅雄性个体携带可去除发声翼结构的突变，由此消除了所有声学信号，并使其免受定向声学寄生蝇的寄生侵扰。我们发现，平翅雄性个体的翼部运动模式，与正常翅雄性个体产生洪亮求偶鸣曲的翼部运动模式并无差异。因发声装置结构组分消失而导致的鸣曲演化丢失，仍保留了正常鸣唱背后高能量消耗的运动行为。本研究结果为残遗行为提供了罕见的实例，并提出这类性状可被招募以行使全新功能的可能性。