Zebra stripes seen as bug defense

BUDAPEST, Hungary, Feb. 9 (UPI) -- A zebra's black and white stripes, puzzling biologists for centuries, may have been an evolutionary defense against biting insects, Hungarian researchers say.

Adam Egri at Eotvos University in Budapest said he and international colleagues confirmed a theory first proposed in 1930 and backed up in 1981 when it was demonstrated biting tsetse flies were least attracted to striped animal models, when compared to black or white models.

Egri says his research shows horseflies -- tabanids -- also avoid the stripes, NewScientist.com reported Thursday

Biting insects transmit several equine diseases, such as equine infectious anemia, as well as leaving painful bites.

At a fly-infested farm in Budapest the researchers painted trays with different black and white patterns, and filled them with salad oil to trap the horseflies.

Trays coated with thick horizontal stripes attracted fewer flies than diagonal lines, or criss-crosses. Thin black stripes like those on a zebra drew fewer flies than thick lines, Egri said.

"The stripes are messing with [the insects'] heads," Justin Marshall, a sensory neurobiologist at the University of Queensland in Australia, said. "It confuses them and provides an unattractive surface to land on."