Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
Department of Anthropology, Hunter College of the City University of New York, New York, NY, USA.
Sci Rep. 2022 Nov 3;12(1):18617. doi: 10.1038/s41598-022-22333-7.
The best-supported hypothesis for why zebras have stripes is that stripes repel biting flies. While this effect is well-established, the mechanism behind it remains elusive. Myriad hypotheses have been suggested, but few experiments have helped narrow the field of possible explanations. In addition, the complex visual features of real zebra pelage and the natural range of stripe widths have been largely left out of experimental designs. In paired-choice field experiments in a Kenyan savannah, we found that hungry Stomoxys flies released in an enclosure strongly preferred to land on uniform tan impala pelts over striped zebra pelts but exhibited no preference between the pelts of the zebra species with the widest stripes and the narrowest stripes. Our findings confirm that zebra stripes repel biting flies under naturalistic conditions and do so at close range (suggesting that several of the mechanisms hypothesized to operate at a distance are unnecessary for the fly-repulsion effect) but indicate that interspecific variation in stripe width is associated with selection pressures other than biting flies.
斑马有条纹的最佳解释是条纹可以驱赶咬人的苍蝇。虽然这种效果已经得到证实，但背后的机制仍然难以捉摸。已经提出了无数的假设，但很少有实验有助于缩小可能的解释范围。此外，真正斑马皮毛的复杂视觉特征和条纹宽度的自然范围在实验设计中基本上被忽略了。在肯尼亚萨凡纳的配对选择野外实验中，我们发现，在一个围栏中释放的饥饿的厩蝇强烈地更喜欢降落在均匀的棕褐色黑斑羚皮上，而不是条纹斑马皮上，但它们在最宽条纹和最窄条纹的斑马物种的皮毛之间没有表现出偏好。我们的发现证实，在自然条件下，斑马条纹可以驱赶咬人的苍蝇，而且在近距离内（这表明在远距离起作用的几种机制对于苍蝇驱避效应来说是不必要的），但这表明条纹宽度的种间变异与除了咬蝇之外的其他选择压力有关。
