The Australian National University, Canberra, Australia.
Biol Lett. 2010 Dec 23;6(6):755-7. doi: 10.1098/rsbl.2010.0384. Epub 2010 Jun 2.
Although conspicuous courtship displays are an effective way of attracting the attention of receptive females, they could provide valuable information to rival males on the location of these females. In fiddler crabs, males that see a receptive female wave their single, greatly enlarged claw in a highly conspicuous courtship display. We test whether other males use this courtship display to alert them to the presence of receptive females that they cannot directly see. We show that male fiddler crabs (Uca mjoebergi) eavesdrop on the courtship displays of nearby males to detect mate-searching females. This allows males to begin waving before a female becomes visible. Furthermore, males appear to adjust their waving according to the information available: eavesdropping males wave 12 times faster than non-courting males but only 1.7 times slower than males in full visual contact with the female.
尽管显眼的求偶展示是吸引有接受能力的雌性注意的有效方式，但它们也可以向竞争对手雄性提供有关这些雌性位置的有价值信息。在招潮蟹中，雄性如果看到一只接受性雌性挥舞着它们那只单独的、明显增大的爪子进行高度显眼的求偶展示，就会知道这一信息。我们测试了其他雄性是否会利用这种求偶展示来提醒它们注意到那些它们无法直接看到的有接受能力的雌性。我们发现雄性招潮蟹（Uca mjoebergi）会偷听附近雄性的求偶展示，以探测正在寻找配偶的雌性。这使得雄性可以在雌性变得可见之前就开始挥舞爪子。此外，雄性似乎会根据可用信息来调整自己的挥舞节奏：偷听的雄性挥舞爪子的速度比不进行求偶的雄性快 12 倍，但只比与雌性完全视觉接触的雄性慢 1.7 倍。
