PDF(Pubmed)
Abstract：
A core assumption of sexual selection theory is that sexually selected weapons, specialized morphological structures used directly in male contests, can improve an individual\'s reproductive success but only if the bearer can overcome associated costs, the negative effects on the bearer\'s fitness components. However, recent studies have shown that producing and wielding exaggerated weapons may not necessarily be costly. Rather, some traits can be selected for supporting, or compensating for, the expense of producing and wielding such exaggerated weapons. In the ant-mimicking jumping spider Myrmarachne gisti, exaggerated chelicerae are borne only by adult males and not females, showing sexual dimorphism and steep positive allometry with body size. Here, we determine the potential benefits of bearing exaggerated chelicerae during male contests and explore the potential for costs in terms of prey-capture efficiency and compensation between chelicera size and neighboring trait size. While males with longer chelicerae won most of their male-male contests, we found no significant differences in prey-capture efficiency between males and females regardless of whether prey was winged or flightless. Males\' elongated chelicerae thus do not impede their efficiency at capturing prey. Furthermore, we found that the sizes of all neighboring traits are positively correlated with chelicera size, suggesting that these traits may be under correlational selection. Taken together, our findings suggest that M. gisti males armed with the exaggerated chelicerae that function as weapons win more fights at limited cost for performance in prey capture and compensate for neighboring structures.
摘要：
性选择理论的一个核心假设是性选择武器，专门的形态结构直接用于男性比赛，可以提高个人的生殖成功率，但前提是持证人可以克服相关的成本，对持票人健身成分的负面影响。然而,最近的研究表明，生产和使用夸大的武器不一定昂贵。相反，可以选择一些特征来支持，或者补偿，生产和使用这种夸张武器的费用。在模仿蚂蚁的跳跃蜘蛛Myrmarachnegisti中，夸张的龟科只由成年男性而不是女性携带，显示性二态性和与体型的急剧正异形。这里,我们确定了在男性比赛中携带夸大的龟头的潜在好处，并探讨了在猎物捕获效率和龟头大小与相邻性状大小之间的补偿方面的潜在成本。虽然长毛的男性赢得了大多数男性-男性比赛，我们发现，无论猎物是有翅膀还是没有飞行，雄性和雌性之间的猎物捕获效率都没有显着差异。因此，雄性细长的鳞翅目不会妨碍它们捕获猎物的效率。此外，我们发现，所有邻近性状的大小都与鳞茎大小呈正相关，这表明这些性状可能处于相关选择之下。一起来看,我们的发现表明，携带夸张的chelicerae作为武器的M.gisti雄性以有限的成本赢得了更多的战斗，以捕获猎物并补偿邻近的结构。
