Dimorphic male midshipman fish: reduced sexual selection or sexual selection for reduced characters?
Dimorphic male midshipman fish: reduced sexual selection or sexual selection for reduced characters?
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DOI：
10.1093/beheco/ark015
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发表时间：
2006-07-01
影响因子：
2.4
通讯作者：
Bass, Andrew H.
中科院分区：
文献类型：
--
作者：
Lee, Jonathan S. F.;Bass, Andrew H.
在大多数具有雄性二态性的分类群中，一些雄性体型较大，第二性征较大（形态夸张），而同一种群中的其他雄性体型较小，第二性征较小（形态弱化）。什么选择压力导致雄性二态性？当a)一些雄性进化出一种形态，在没有性别选择压力的情况下，这种形态可以减少能量和发育成本，或者b)一些雄性选择另一种形态，这种形态在另一种行为策略（如绿帽子）中表现良好。这两种机制可以一起起作用，但理论上每一种机制都足以驱动二态态。在这里，我们在普通鳍鱼（Porichthys notatus）中测试了假设“b”（减少性状的性选择）。在夸张的雄性形态（类型1）中，领地性和绿帽子之间的行为可塑性允许直接比较夸张的雄性形态和减少的雄性形态（类型11）的绿帽子。与I型绿帽子者相比，11型绿帽子者；在被领地I型雄性追逐之前，能够在巢穴附近停留更长的时间，这表明11型的形态减少了11型雄性在被领地I型雄性攻击前的时间。结合其他研究表明性选择在维持夸大的形态中所起的作用，这些数据支持了“减少特征的性选择”假说，并阐明了性选择如何以不同的方式作用于不同的雄性，以维持同一物种内的两种雄性形态。
In most taxa with male dimorphisms, some males are large in body size with exaggerated secondary sexual characters (exaggerated morph), whereas other males in the same population are small and have reduced secondary sexual characters (reduced morph). What selective pressures cause male dimorphisms? Reduced morphologies may result when a) some males develop a morphology that, in the absence of sexual selection pressures for an exaggerated morphology, reduces energetic and developmental costs and/or b) some males opt for an alternative morphology that does well at an alternative behavioral tactic such as cuckoldry. The 2 mechanisms could act together, but each alone is theoretically sufficient to drive dimorphisms. Here, we tested hypothesis "b" (sexual selection for reduced characters) in the plainfin midshipman fish, Porichthys notatus. Behavioral plasticity between territoriality and cuckoldry in an exaggerated male morph (type 1) allows for a direct comparison of cuckoldry by exaggerated morph males to cuckoldry by reduced morph (type 11) males. Compared with type I cuckolders, type 11 cuckolders; were able to remain near the nest for longer periods before being chased by the territorial type I male, suggesting that the reduced type 11 morphology allows type 11 males to prolong the time before attack by territorial males. Combined with other studies showing a role of sexual selection in maintaining the exaggerated morph, the data support the "sexual selection for reduced characters" hypothesis and elucidate how sexual selection can act in different ways on different males to maintain 2 male morphologies within a single species.