Flying high: Horse research recognised with Ig Nobel Prize

During the experiment the scientists used plastic horses covered in glue. In the picture, a black horse covered with horse-flies. Photo: G. Horvath
During the experiment the scientists used plastic horses covered in glue. The picture shows a black horse covered with horse flies. Photo: Gábor Horváth

Horse-related research carried out by a team of European scientistsas been recognised with an Ig Nobel Prize.

The annual Ig Nobel Prizes, a play on the word ignoble, have been awarded since 1991 and are a parody of the Nobel Prizes.

The awards are organised by the scientific humor magazine Annals of Improbable Research with the stated aim to “honor achievements that first make people laugh, and then make them think”.

While the 10 awards given annually can highlight seemingly absurd research, they can also recognise unusual avenues of study that can yield useful knowledge, as was the case with the research by Susanne Åkesson, a professor of evolutionary ecology at Sweden’s Lund University, and her colleagues from Hungary and Spain.

Lund University was quick to acknowledge the efforts of Åkesson, who shares the prize with six other researchers, Gábor Horváth, Miklós Blahó, György Kriska, Ramón Hegedüs, Balázs Gerics and Róbert Farkas.

They discovered that white horses weren’t particularly bothered by blood-sucking horse-flies. Why? Well, in simple terms, because they are white. Their efforts were honored in the Physics category.

Åkesson travelled to the award ceremony at Harvard University in Boston to receive the award this week.

The research was presented six years ago in an article in the scientific journal Proceedings of the Royal Society B. The article revealed that white horses were not bothered by blood-sucking horse-flies in the same way as their darker fellow species members.

They explained in their paper, “An unexpected advantage of whiteness in horses: the most horsefly-proof horse has a depolarizing white coat”, that when the sun shines on a dark, black or brown coat, it reflects a signal – a linear polarised light – in the same direction as the horizon.

The signal is the same as when sunlight is reflected from a water surface. It can be detected by horse-flies (tabanidae) looking for water where they can lay eggs on aquatic plants and in shrubs near the water. This is an important part of the life cycle of the horse-fly as the larvae, once they have hatched, fall into the water where they continue to develop. The polarised light reflected from a dark coat also sends out a signal to females that this is a place where they can find blood, and a solid meal of blood can enable the female horse-fly to lay more eggs.

In contrast, white horses reflect an unpolarised light – that is, the light vibrates not only in one but in several directions perpendicular to that of the light, and for the horse-fly this is very hard to detect.

In later studies, Åkesson and her colleagues continued their research in this area and concluded that a striped coat is even better than a white one at avoiding being bitten by blood-sucking horse-flies.

Ever since Alfred Russell Wallace and Charles Darwin discussed the topic in the late 1800s, the prevailing theory has been that zebras initially developed their striped patterns to avoid attacks from predators. But in light of their results, the present researchers argue that the zebra developed its stripes to protect them from blood-sucking horse-flies, rather than a lion on the hunt.

One of the results of Susanne Åkesson’s research is that there are now zebra-striped horse covers.

The original paper can be read here

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