Do Zebra Stripes Confuse Biting Flies?
Zebra stripes have fascinated people for millennia, and there are a number of different theories to explain why these wild horses should be so brightly marked. A handful of laboratories around the world – including one lead by UC Davis wildlife biologist Tim Caro – have been putting these theories to the test. A new paper from Caro’s group, led by Ken Britten at the UC Davis Center for Neuroscience, puts a hole in one idea: that the stripes confuse biting flies by breaking up polarized light.
The paper is published in the May 25 issue of PLOS ONE.
Britten said Caro brought him in as a vision specialist on the project to understand why flies would or would not be attracted to zebra stripes. Horse flies and tsetse flies are common in the regions of Africa where zebras live. Not only do they suck their host’s blood, but they also carry diseases – for example tsetse notoriously spread trypanosome parasites that cause disease in wild animals, livestock and people (the human disease is known as sleeping sickness). Horse flies in particular can carry diseases fatal to equids.