白馬在野外的生存很艱難。它們被證明患上了一種皮膚癌,，并且更容易遭到食肉動(dòng)物的攻擊,。但是白馬卻有一個(gè)優(yōu)勢(shì)：與棕馬或黑馬相比，它們對(duì)吸血的馬蠅的吸引力要低得多,。
據(jù)美國(guó)《科學(xué)》雜志在線新聞報(bào)道,，這一結(jié)果與物理學(xué)因素有關(guān)。研究人員發(fā)現(xiàn)，這些馬蠅通過(guò)偏振光來(lái)追蹤獵物——馬匹光澤的皮毛會(huì)反射大量的偏振光,。然而白馬蒼白的皮毛卻會(huì)反射大量的非偏振光,。這些不規(guī)則的信號(hào)似乎在告訴饑餓的馬蠅：“我不好吃。”研究人員在2月3日的英國(guó)《皇家學(xué)會(huì)學(xué)報(bào)B卷》（Proceedings of the Royal Society B）網(wǎng)絡(luò)版上報(bào)告了這一發(fā)現(xiàn),。（生物谷Bioon.com）
生物谷推薦原始出處：
Proceedings of the Royal Society B February 3, 2010, doi: 10.1098/rspb.2009.2202
An unexpected advantage of whiteness in horses: the most horsefly-proof horse has a depolarizing white coat
Gábor Horváth1,*, Miklós Blahó1, Gy?rgy Kriska2, Ramón Hegedüs3, Balázs Gerics4, Róbert Farkas5 and Susanne ?kesson6
1Environmental Optics Laboratory, Department of Biological Physics, Physical Institute, E?tv?s University, 1117 Budapest, Pázmány sétány 1, Hungary
2Group for Methodology in Biology Teaching, Biological Institute, E?tv?s University, 1117 Budapest, Pázmány sétány 1, Hungary
3Computer Vision and Robotics Group, University of Girona, Campus de Montilivi, Edifici P4, 17071 Girona, Spain
4Faculty of Veterinary Science, Department of Anatomy and Histology, Szent István University, 1078 Budapest, István u. 2, Hungary
5Faculty of Veterinary Science, Department of Parasitology and Zoology, Szent István University, 1078 Budapest, István u. 2, Hungary
6Department of Animal Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden
White horses frequently suffer from malign skin cancer and visual deficiencies owing to their high sensitivity to the ultraviolet solar radiation. Furthermore, in the wild, white horses suffer a larger predation risk than dark individuals because they can more easily be detected. In spite of their greater vulnerability, white horses have been highly appreciated for centuries owing to their natural rarity. Here, we show that blood-sucking tabanid flies, known to transmit disease agents to mammals, are less attracted to white than dark horses. We also demonstrate that tabanids use reflected polarized light from the coat as a signal to find a host. The attraction of tabanids to mainly black and brown fur coats is explained by positive polarotaxis. As the host's colour determines its attractiveness to tabanids, this parameter has a strong influence on the parasite load of the host. Although we have studied only the tabanid–horse interaction, our results can probably be extrapolated to other host animals of polarotactic tabanids, as the reflection–polarization characteristics of the host's body surface are physically the same, and thus not species-dependent.
