Honest sexual signaling in turtles: experimental evidence of a trade-off between immune response and coloration in red-eared sliders Trachemys scripta elegans

摘要: Sexual signals can be evolutionarily stable if they are honest and condition dependent or costly to the signaler. One possible cost is existence of a trade-off between maintaining immune system elaboration ornaments. This hypothesis has been experimentally tested in some groups animals but not others such as turtles. We challenged female red-eared sliders Trachemys scripta elegans, with bacterial antigen (lipopolysaccharide (LPS)) without pathogenic effects explore whether activation affected visual colorful ornaments head. The LPS injection altered reflectance patterns color In comparison control animals, yellow chin stripes injected exhibited (1) reduced brightness, (2) lower long wavelength (>470 nm) reflectance, (3) values for carotenoid chroma. postorbital patches individuals also showed very (>570 nm) did change Thus, experimental turtles darker less “yellowish” “reddish” at end experiment, whereas their coloration. first evidence supporting expression suggest that this may allow honestly signal individual quality via characteristics coloration, which have an important role intersexual selection processes.