Fighting with an unreliable weapon: opponent choice and risk avoidance in fiddler crab contests
Fighting with an unreliable weapon: opponent choice and risk avoidance in fiddler crab contests
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DOI：
10.1007/s00265-016-2094-2
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发表时间：
2016-04
影响因子：
2.3
通讯作者：
Daisuke Muramatsu;T. Koga
中科院分区：
文献类型：
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作者：
Daisuke Muramatsu;T. Koga
摘要目前的信号理论预测动物的信号通常是诚实的，但每种信号系统都允许一些欺骗的混合。雄性招潮蟹会利用它们长在左侧或右侧的大爪进行激烈的战斗。有些雄蟹有脆弱的再生爪（再生雄蟹），有些雄蟹有强健的原始爪（原始雄蟹），但螃蟹在视觉上无法区分这两种类型。在本研究中，我们对一群uca乳牛进行了实地观察，以研究再生的雄性如何使用它们的劣势武器进行战斗，以及其他雄性如何应对潜在的欺骗。再生的雄性使用恐吓策略；他们假装咄咄逼人以威慑对手，但在战斗升级时投降了。再生的雄性倾向于选择体型更小、手相对的对手，可能是因为在同手搏斗中，爪子可以紧紧抓住。恫吓策略似乎是部分成功的，因为再生雄性没有选择性地受到其他雄性的挑战，并且在41.7%的情况下击败了原始雄性。然而，原始的雄性进化出了对抗虚张声势的策略，比如选择同手的对手，即使对手更大，也要坚持比赛。因此，在42.9%的情况下，原始雄性打败了拥有更长的爪子的再生雄性。在最令人震惊的案例中，一只原始雄性将一只常驻雄性驱逐出洞穴，尽管它的爪子再生了42.7%。这种反虚张声势策略减少了对力量信号（武器大小）的依赖，限制了虚张声势的好处。雄性招潮蟹（Uca lactea）用其长在左侧或右侧的主爪进行战斗。然而，具有脆弱的再生爪子的雄性（再生雄性）与原始爪子大小相似，在战斗中会欺骗。再生的雄性使用恐吓策略；他们表现得咄咄逼人，以威慑对手，但在战斗升级时投降了。它们选择了体型较小且手相对的对手，因为在同手搏斗中，爪子可以紧紧抓住。结果，在41.7%的情况下，它们用原始爪（原始雄性）击败了雄性。然而，有趣的是，原始的雄性进化出了一种对抗虚张声势的策略：它们选择同手的对手，即使对手更大，它们也会坚持比赛。因此，42.9%的原始雄性打败了配备更大爪子的再生雄性。这种反虚张声势策略的作用是“揭穿虚张声势”，限制虚张声势的好处。
AbstractCurrent signaling theories predict that animal signals are generally honest, but each signaling system allows some admixture of deception. Male fiddler crabs fight aggressively through use of their greatly enlarged major claw, which grows on the left or right side. Some males have fragile regenerated claws (regenerated males) and others have robust original claws (original males), but crabs cannot visually discriminate between the two types. In the present study, we conducted field observations in a population ofUca lacteato investigate how regenerated males fight with their inferior weapons, and how other males deal with the potential deception. Regenerated males employed bluffing tactics; they pretended to be aggressive to deter opponents, but surrendered when the fight escalated. Regenerated males tended to choose smaller and opposite-handed opponents, probably because claws can be grappled tightly in same-handed fights. The bluffing tactics seemed to be partially successful, because regenerated males were not selectively challenged by other males and defeated original males in 41.7 % of the cases. However, original males developed counter-bluff tactics, such as choosing same-handed opponents and persisting in contests even when the opponent was larger. Consequently, original males defeated regenerated males equipped with longer a claw in 42.9 % of the cases. In the most striking case, an original male evicted a resident male from his burrow despite the 42.7 % longer regenerated claw. This counter-bluff tactic decreases the reliance on the signal of strength (weapon size) and limits the benefit of bluffing.Significance statementMale fiddler crab (Uca lactea) fight with their major claw, which grows on either the left or right side. However, males with fragile a regenerated claw (regenerated males) which were similar in size to an original claw made deception in the fights. Regenerated males employed bluffing tactics; they behaved aggressively to deter opponents, but surrendered when the fight escalated. They chose smaller and opposite-handed opponents, because claws can be grappled tightly in same-handed fights. As a result, they defeated males with an original claw (original males) in 41.7 % of the cases. Interestingly, however, original males developed a counter-bluff tactic: they chose same-handed opponents and persisted in contests even when the opponent was larger. Consequently, 42.9 % of original males defeated regenerated males equipped with a larger claw. This counter-bluff tactic serves to “call the bluff” and limit the benefits of bluffing.