Potential mates may be attracted to the males in flamboyant jumping spider species because of their bright eyes and scarlet-coloured feet.
It turns out that spiders can’t see their vivid red bodies.
That’s because Saitis barbipes, a common jumping spider found in Europe and North Africa, is actually colour-blind, according to a new study.
Researchers from University of Hamburg and University of Cincinnati discovered that spiders do not have the red photoreceptor in their eyes.
The experts also looked inside the eye for colored filters that might change the red-green sensitivity.
It was previously thought that red barbipes on male Saitis Barbipes could be an addition to the elaborate courtship dances they use for winning over discerning women.
Saitis barbipes are a jumping spider common in Europe and North Africa. However, they lack the ability to detect red light in their eyes according to an international research team.
Researchers from University of Hamburg and University of Cincinnati discovered that spiders have no photoreceptor to red.
We assumed that they communicated using color. David Outomuro is a UC postdoctoral research fellow now at the University of Pittsburgh.
Biologists collected spiders in Slovenia for lab study in Germany and used microspectrophotometry at UC to identify photoreceptors sensitive to various light wavelengths or colours.
They found no evidence of a red photoreceptor but instead identified patches on the spider that strongly absorb ultraviolet wavelengths to appear as bright ‘spider green’ to other jumping spiders.
Researchers concluded that the red colors we see are likely to be similar to black marks on jumping spiders.
Professor Morehouse stated, “It’s quite a puzzle what’s happening here.” “We still haven’t solved what the red is doing.”
Colour is used by animals in many ways.
Professor Morehouse says that bright colors can be confusing.
“We talked a lot about it together. Is there anything more? He said that he felt there was an intriguing story to the mystery.
Cynthia Tedore was a Research Associate at University of Hamburg. The results were unexpected.
“Males display bold reds and blacks on their forward-facing body surfaces, which they use during their courtship dances. However, the females are devoid of any red pigmentation,” she stated.
“This first suggested that the red color played a role in our mate attraction.
“Instead, however, we discovered that black and red are equally or almost so perceived by these spiders. Red is perceived differently from black and is therefore perceived as dark “spider-green” instead of red.
Research suggests that red-and-black colours may help the spider camouflage itself.
Tedore stated that predators with red eyes should be able to see the red colour of the spider from a distance. The red and black color patches can then blend together, creating an intermediate colour orangish-brownish. This would allow the spider to blend into its litter habitat more effectively than all-black.
One possibility was that red barbipes on the male Saitis Barbipes could be used to complement their intricate courtship dances in order to seduce discerning females.
Biologists collected spiders in Slovenia for lab study and used microspectrophotometry at UC to identify photoreceptors sensitive to various light wavelengths or colours
Instead of finding evidence for a red photoreceptor, they discovered patches that absorb UV wavelengths and made the spider appear brighter than other jumping spiders.
Numerous jumping spiders in bright colors see perfectly red, however Morehouse stated that this is an example of animals’ ability to perceive the world differently from humans.
Sunscreen absorbs UV light very well but is invisible to us.
‘If aliens could study us, they might wonder, “Why did their bodies have UV-absorbing colors when they went to the beach?” Professor Morehouse explained that our perceptions of ultraviolet light are completely absent, and we do not know why sunscreen creates these bright colours.
The research also highlights how we might need to think about the differences in animal vision when designing our own world.
“What would a wind turbine, a car window, or high-rise look to a bird who might come into contact with it?” Professor Morehouse agreed.
“We should consider the possibility of their perceptual worlds coexisting. It’s fascinating, however, to see ourselves in the shoes of other animals who experience the world differently than we do.
The Science of Nature published this study.