Prenter John, Pérez-Staples Diana, Taylor Phillip W
Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
BMC Res Notes. 2010 Nov 16;3:306. doi: 10.1186/1756-0500-3-306.
Locomotor performance in ecologically relevant activities is often linked to individual fitness. Recent controversy over evolution of extreme sexual size dimorphism (SSD) in spiders centres on the relationship between size and locomotor capacity in males. Advantages for large males running over horizontal surfaces and small males climbing vertically have been proposed. Models have implicitly treated running and climbing as functionally distinct activities and failed to consider the possibility that they reflect common underlying capacities.
We examine the relationship between maximum climbing and running performance in males of three spider species. Maximum running and climbing speeds were positively related in two orb-web spiders with high SSD (Argiope keyserlingi and Nephila plumipes), indicating that for these species assays of running and climbing largely reveal the same underlying capacities. Running and climbing speeds were not related in a jumping spider with low SSD (Jacksonoides queenslandica). We found no evidence of a performance trade-off between these activities.
In the web-spiders A. keyserlingi and N. plumipes good runners were also good climbers. This indicates that climbing and running largely represent a single locomotor performance characteristic in these spiders, but this was not the case for the jumping spider J. queenslandica. There was no evidence of a trade-off between maximum running and climbing speeds in these spiders. We highlight the need to establish the relationship between apparently disparate locomotor activities when testing alternative hypotheses that yield predictions about different locomotor activities. Analysis of slopes suggests greater potential for an evolutionary response on performance in the horizontal compared to vertical context in these spiders.
在与生态相关的活动中，运动能力通常与个体健康状况相关。近期关于蜘蛛极端两性体型差异（SSD）进化的争议集中在雄性蜘蛛体型与运动能力之间的关系上。有人提出大型雄性蜘蛛在水平面上奔跑具有优势，而小型雄性蜘蛛在垂直面上攀爬具有优势。以往的模型隐含地将奔跑和攀爬视为功能上不同的活动，并且没有考虑到它们可能反映共同潜在能力的可能性。
我们研究了三种蜘蛛雄性个体的最大攀爬能力与奔跑能力之间的关系。在两种具有高度两性体型差异的圆蛛（克氏黄金圆蛛和横纹金蛛）中，最大奔跑速度和最大攀爬速度呈正相关，这表明对于这些物种而言，奔跑和攀爬测试在很大程度上揭示了相同的潜在能力。在一种两性体型差异较小的跳蛛（昆士兰杰氏跳蛛）中，奔跑速度和攀爬速度没有相关性。我们没有发现这些活动之间存在性能权衡的证据。
在圆蛛克氏黄金圆蛛和横纹金蛛中，善于奔跑的个体也善于攀爬。这表明在这些蜘蛛中，攀爬和奔跑在很大程度上代表了单一的运动性能特征，但对于跳蛛昆士兰杰氏跳蛛而言并非如此。在这些蜘蛛中，没有证据表明最大奔跑速度和最大攀爬速度之间存在权衡。我们强调，在检验对不同运动活动产生预测的替代假设时，需要确定明显不同的运动活动之间的关系。斜率分析表明，与垂直环境相比，这些蜘蛛在水平环境中性能进化响应的潜力更大。
