Natures wonders: zebra stripes thwart flies (Introduction)

by David Turell , Sunday, February 26, 2023, 15:57 (418 days ago) @ David Turell

Studies with different blanket patterns proved it:

https://www.sciencealert.com/we-now-know-why-zebras-stripes-are-so-effective?utm_source...

"'We knew that horse flies are averse to landing on striped objects," says evolutionary ecologist Tim Caro from the University of Bristol in the UK. "A number of studies have now shown this, but it is not clear which aspects of stripes they find aversive."

"'Is it the thinness of the stripes? The contrast of black and white? The polarized signal that can be given off objects? So we set out to explore these issues using different patterned cloths draped over horses and filmed incoming horse flies."

"While the horse flies were most attracted to large dark objects in their environment – with all-gray blankets resulting in the most landings – once the dark color is broken up with some white, the flies become less keen to interact.

"Coats with large black triangles placed in different positions were shown to be the next most popular design amongst flies, followed by coats with small checkerboard patterns. Stripes were the most off-putting for flies, with higher contrast stripes attracting the fewest fly landings during tests.

"The researchers think the key is eliminating the strong outline of a large dark patch in the field of view of horse flies, something which stark black and white stripes do rather well. In other words, it means zebras look like less of a target.

***

"Based on the findings of this study, the flies aren't being put off by any kind of optical illusion effect or by light polarization (certain parts of the zebra appearing brighter). The pattern of thin stripes that acts as a kind of camouflage after all; not against large predators, but tiny ones.

"Scientists have been trying to figure out the purpose of the zebra's stripes for years – it's previously been suggested that they're some kind of temperature control mechanism or a way of confusing approaching horse flies.

"The next question up for debate is why are zebras the only hoofed mammals we know of to have evolved this special design on their bodies. That's something that can be looked at in the future.

Comment: strangely, in Africa zebras stood out, but then I'm not a fly. Is this a God design?