Scientists found zebra‘s black strips prevents bloodsuckers to feed on them. We all know that formal studies say a zebra’s black-and-white stripes camouflage the animal in tall grass—the better to evade the colorblind lion.
But a new study says the pattern scrambles the vision of a tinier biter: the bloodsucking horseflies.
Only the female horseflies are bloodsuckers
Female horseflies which feed on blood, are attracted to polarized light—light waves that are oriented in a particular direction and that we experience as glare. This glare lures the bugs most likely because it resembles light reflected off water, where they lay their eggs.
What do researchers have to say?
Researchers from the University of Bristol in the UK and the University of California (UC) Davis in the US have added evidence to the theory that the primary purpose of zebras’ stripes is for avoiding blood-sucking parasites.
The researchers investigated the behaviors of Tabanidae horse flies around captive zebras and domestic horses at a livery in North Somerset, using video analysis techniques.
Experiments and further approaches to understanding zebra’s behaviors against horseflies
In a video, it is observed that the horse flies just seem to fly over zebra stripes or bump into them, but this did not happen with horses. Consequently, far fewer successful landings were experienced by zebras compared to horses,” said Professor Tim Caro from the University of Bristol.
Their second experiment was to observe horse fly behavior around the same horses wearing different colored cloth coats: black, white, or zebra-striped livery. This excluded any differences in behavior or smell between horses and zebras.
Conclusion of the two types of research and experiments
Stripes may dazzle flies in some way once they are close enough to see them with their low-resolution eyes,” one of the researchers said in a statement.
The research also directly observed zebra and horse behavior in response to biting flies. Zebras exhibited preventative behavior, such as running away and tail swishing at a far higher rate than horses.
Disease which is spread by horseflies to zebra and horses
Zebras which are native to Africa, the horse flies carry dangerous debilitating diseases such as trypanosomiasis and African horse sickness which cause wasting and often death, researchers said. Unsurprisingly, zebras utilize both behavioral defenses and morphological striping to avoid horse flies, they said.
This research provides new evidence for the theory that zebras evolved dichromatic striped coats to evade biting flies and has considerable implications for the horse industry.