University of Hyogo/Museum of Nature and Human Activities, 6 Yayoigaoka, Sanda, Hyogo, 669-1546, Japan.
School of Human Sciences, Kobe College, Okadayama 4-1, Nishinomiya, Hyogo, 662-8505, Japan.
Sci Rep. 2020 Oct 26;10(1):18279. doi: 10.1038/s41598-020-75010-y.
Accurate morphological ant mimicry by Myrmarachne jumping spiders confers strong protective benefits against predators. However, it has been hypothesized that the slender and constricted ant-like appearance imposes costs on the hunting ability because their jumping power to capture prey is obtained from hydraulic pressure in their bodies. This hypothesis remains to be sufficiently investigated. We compared the jumping and prey-capture abilities of seven Myrmarachne species and non-myrmecomorphic salticids collected from tropical forests in Malaysian Borneo and northeastern Thailand. We found that the mimics had significantly reduced abilities compared with the non-mimics. The analysis using geometric morphometric techniques revealed that the reduced abilities were strongly associated with the morphological traits for ant mimicry and relatively lower abilities were found in Myrmarachne species with a more narrowed form. These results support the hypothesis that the jumping ability to capture prey is constrained by the morphological mimicry and provide a new insight into understanding the evolutionary costs of accurate mimicry.
跳蛛科拟态蚂蚁的形态能够提供精准的保护，免受捕食者的侵害。然而，有人假设这种细长且收缩的蚂蚁状外观会对捕食能力造成影响，因为它们跳跃以捕捉猎物的力量来自于身体内的液压。这个假设仍需要充分研究。我们比较了来自马来西亚婆罗洲和泰国东北部热带森林的七种拟态跳蛛和非拟态的跳蛛科蜘蛛的跳跃和捕食能力。我们发现，与非拟态蜘蛛相比，拟态蜘蛛的能力显著降低。通过几何形态测量技术的分析表明，这种能力的降低与蚂蚁拟态的形态特征密切相关，而且在形态更狭窄的拟态跳蛛物种中发现了相对较低的能力。这些结果支持了这样的假设，即捕食猎物的跳跃能力受到形态拟态的限制，并为理解精确拟态的进化成本提供了新的视角。
