Evidence for and against red camouflage in jumping spiders (Saitis barbipes)

Investigating how an animal’s color patterns stand out to different observers is critical to understanding animal function. This study examines the special case of jumping spiders (Cytis Barbipes) The male displays red and black ornaments during courtship, even though he is apparently unable to distinguish between these colors. We believe that when seen through the eyes of a predator, red may actually be a better match than black for the spider’s fallen leaf background, and that the black edge of the hairs surrounding the red ornament is a natural predator. We suggest that the person’s acuity and observation distance may produce a blurred background in red. – Matches desaturated red. In a field experiment, we tested whether red ornaments reduced predation compared to red ornaments painted black and found that, unexpectedly, spiders with red ornaments were predated more often. I understand. Having established that birds are the main predators of spiders, we use an avian visual camera to photograph spiders in their natural habitat. Red has a similar color contrast with the background than black, but you can see that achromatic colors have less contrast. Also, with typical avian visual acuity and viewing distances, the red and black elements are blurred together, making the chromatic and achromatic colors more distinct from the background than what appears to animals with higher visual acuity or closer viewing distances. I also noticed that the contrast was lower. Interestingly, red ornaments appear orange or yellow when viewed from an angle, reducing achromatic contrast with the background but not chromatic contrast. Although our imaging results support the hypothesis that red is camouflaging, the results of predation experiments do not. Therefore, the functional significance of red color in spiders remains unresolved.

Gerfen, JL, Tedore, C. Hidden in red: The pros and cons of red camouflage in jumping spiders (Cytis Barbipes). science nuts 11158 (2024). https://doi.org/10.1007/s00114-024-01945-1