School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Proc Biol Sci. 2010 Jun 22;277(1689):1923-8. doi: 10.1098/rspb.2009.2196. Epub 2010 Feb 24.
The most commonly assumed cost for exaggerated male ornamentation is increased predation pressure owing to decreased locomotor performance or increased conspicuousness to predators. Despite its intuitive basis, the locomotor costs of male ornamentation are not well established. We tested the hypothesis that multiple male signals that are used independently during female choice and male competition could lead to varied locomotor costs. Multiple signals with varied costs could provide a more detailed indicator of overall male quality, as only the highest-quality individuals could support all costs. To test this idea, we investigated the burst locomotor consequences of multiple ornaments for males of the pacific blue-eye (Pseudomugil signifer). We evaluated five competing models relating body size, ornament size and performance traits to field measures of dominance and attractiveness. Non-propulsive male fin ornaments used during male competition were different from those used in female choice. First dorsal fin length was the most important predictor of male attractiveness, while dominance was only associated with anal fin length. Furthermore, first dorsal fin length was positively correlated with swim speed, while anal fin length was negatively associated with speed. Our study shows that multiple male signals that are used independently during male competition and female choice also differ in their associated costs. This provides a mechanism for understanding why locomotor costs for exaggerated male ornamentation are not often empirically demonstrated.
雄性夸张装饰物最常被假定的成本是由于运动表现下降或对捕食者的可见度增加而导致的捕食压力增加。尽管这种假设具有直观的基础,但雄性装饰物的运动成本尚未得到很好的确定。我们检验了这样一个假设,即用于雌性选择和雄性竞争的多个雄性信号可能会导致不同的运动成本。具有不同成本的多种信号可以提供更详细的整体雄性质量指标,因为只有最高质量的个体才能支持所有成本。为了验证这个想法,我们研究了雄性太平洋蓝眼鱼(Pseudomugil signifer)多种装饰物对其爆发式运动的影响。我们评估了五个竞争模型,这些模型将体型、装饰物大小和性能特征与实地测量的支配力和吸引力联系起来。在雄性竞争中使用的非推进性雄性鳍装饰物与用于雌性选择的装饰物不同。第一背鳍长度是雄性吸引力的最重要预测因子,而支配力仅与臀鳍长度有关。此外,第一背鳍长度与游泳速度呈正相关,而臀鳍长度与速度呈负相关。我们的研究表明,在雄性竞争和雌性选择中独立使用的多种雄性信号在相关成本上也存在差异。这为理解为什么夸张的雄性装饰物的运动成本通常没有被经验证明提供了一种机制。