Odum School of Ecology, The University of Georgia, Athens, Georgia, United States of America.
PLoS One. 2012;7(7):e41323. doi: 10.1371/journal.pone.0041323. Epub 2012 Jul 25.
The distinctive orange and black wings of monarchs (Danaus plexippus) have long been known to advertise their bitter taste and toxicity to potential predators. Recent work also showed that both the orange and black coloration of this species can vary in response to individual-level and environmental factors. Here we examine the relationship between wing color and flight performance in captive-reared monarchs using a tethered flight mill apparatus to quantify butterfly flight speed, duration and distance. In three different experiments (totaling 121 individuals) we used image analysis to measure body size and four wing traits among newly-emerged butterflies prior to flight trials: wing area, aspect ratio (length/width), melanism, and orange hue. Results showed that monarchs with darker orange (approaching red) wings flew longer distances than those with lighter orange wings in analyses that controlled for sex and other morphometric traits. This finding is consistent with past work showing that among wild monarchs, those sampled during the fall migration are darker in hue (redder) than non-migratory monarchs. Together, these results suggest that pigment deposition onto wing scales during metamorphosis could be linked with traits that influence flight, such as thorax muscle size, energy storage or metabolism. Our results reinforce an association between wing color and flight performance in insects that is suggested by past studies of wing melansim and seasonal polyphenism, and provide an important starting point for work focused on mechanistic links between insect movement and color.
帝王蝶（Danaus plexippus）的翅膀具有独特的橙色和黑色，长期以来一直被认为是向潜在捕食者表明其苦味和毒性的标志。最近的研究还表明，这种物种的橙色和黑色着色都可以根据个体水平和环境因素而变化。在这里，我们使用系绳飞行仪装置检查了圈养饲养的帝王蝶的翅膀颜色与飞行性能之间的关系，以量化蝴蝶的飞行速度、持续时间和距离。在三个不同的实验（共 121 只个体）中，我们在飞行试验之前使用图像分析来测量新出现的蝴蝶的身体大小和四个翅膀特征：翅膀面积、长宽比（长度/宽度）、黑化和橙色色调。结果表明，在控制性别和其他形态特征的分析中，翅膀橙色较深（接近红色）的帝王蝶比翅膀橙色较浅的帝王蝶飞行距离更长。这一发现与过去的研究一致，即在野外的帝王蝶中，那些在秋季迁徙期间采样的蝴蝶比非迁徙的帝王蝶颜色更深（更红）。这些结果表明，在变态过程中色素沉积到翅膀鳞片上可能与影响飞行的特征有关，例如胸部肌肉大小、能量储存或代谢。我们的结果加强了过去对翅膀黑化和季节性多态性的研究中提出的昆虫翅膀颜色与飞行性能之间的联系，并为专注于昆虫运动和颜色之间的机制联系的工作提供了重要的起点。
