Interacting Effects of Eyespot Number and Ultraviolet Reflectivity on Predation Risk in Bicyclus anynana (Lepidoptera: Nymphalidae)
Interacting Effects of Eyespot Number and Ultraviolet Reflectivity on Predation Risk in Bicyclus anynana (Lepidoptera: Nymphalidae)
复制标题
DOI：
10.1093/jisesa/iez123
复制
发表时间：
2019-12-12
影响因子：
2.2
通讯作者：
Monteiro, Antonia
中科院分区：
文献类型：
--
作者：
Chan, Ian Z. W.;Rafi, Fathima Zohara;Monteiro, Antonia
鳞翅目动物翅膀边缘的小眼点是吸引捕食者注意力以转移攻击的明显因素，但这些模式中心的紫外线反射率和眼点数量的变化在改变眼点功能中的作用尚不清楚。在此，我们基于眯眼灌木棕蝶（Bicyclus anynana, 1879）的外观，进行了一项基于野外的人工猎物捕食实验。我们测试了翅膀图案的两种视觉特性是如何影响捕食风险的：i)腹侧前翼表面的眼点数量——两个或四个；ii)眼斑中心的紫外线反射率正常（中心的紫外线反射率与周围较暗的环形成强烈对比）或遮挡（这种对比减弱）。在两个地点共部署了807个猎物。我们发现腹前眼斑的数量与眼斑中心的紫外线反射率之间存在显著的相互作用：在眼斑较少的项目中，阻挡紫外线导致捕食风险增加，而在眼斑较多的项目中，阻挡紫外线导致捕食风险降低。如果纸上模型的高捕食率可以等同于高水平的翼缘/眼点显著性，这些结果表明，紫外线反射率是使眼点对捕食者更明显的一个重要因素，并表明特定蝴蝶眼点数量变异的适合度可能取决于其中心是否存在紫外线以及当地捕食者协会检测紫外线的能力。
Small marginal eyespots on lepidopteran wings are conspicuous elements that attract a predator's attention to deflect attacks away from the body, but the role of ultraviolet (UV) reflectivity at the center of these patterns and variation in eyespot number in altering the function of eyespots remains unclear. Here, we performed a field-based predation experiment with artificial prey items based on the appearance of squinting bush brown butterflies Bicyclus anynana (Butler, 1879). We tested how two visual properties of the wing pattern affect predation risk: i) the number of eyespots on the ventral forewing surface-two or four; and ii) the UV reflectivity of eyespot centers-normal (where the UV reflectivity of the centers contrasts strongly with that of the darker surrounding ring) or blocked (where this contrast is reduced). In total, 807 prey items were deployed at two sites. We found a significant interaction between the number of ventral forewing eyespots and UV reflectivity in the eyespot centers: in items with fewer eyespots, blocking UV resulted in increased predation risk whereas in items with more eyespots, blocking UV resulted in decreased predation risk. If higher predation of paper models can be equated with higher levels of wing margin/ eyespot conspicuity, these results demonstrate that UV reflectivity is an important factor in making eyespots more conspicuous to predators and suggest that the fitness of particular butterfly eyespot number variants may depend on the presence or absence of UV in their centers and on the ability of local predator guilds to detect UV.