Intrinsic climatic predictability affects ornamental coloration of adult males: Evidence for compensation among carotenoid- and melanin-based coloration

Abstract

1. Ornamental coloration is frequently an honest signal of quality associated with sexual selection. While changes in average environmental conditions affect carotenoid-and melanin-based coloration, no evidence exists that changes in intrinsic environmental predictability affect coloration. 2. Here we experimentally manipulated the intrinsic predictability of precipitation in semi-natural populations of common lizards Zootoca vivipara and tested its effect on ornamental coloration and reproduction of adult males. 3. Less predictable precipitation decreased hue of carotenoid-based coloration and the extent of melanin-based coloration. Hue was positively correlated and the extent of melanin-based coloration was negatively correlated with the male's number of confirmed mate partners. 4. Treatment effects on hue were associated with reduced, and treatment effectson the extent of melanin-based coloration with increased access to females, in line with differential effects on sexual selection. 5. Neither survival nor reproductive success of adult males significantly differed among predictability treatments, suggesting that negative effects on reproduction caused by changes in carotenoid-basedcoloration may have been compensated by changes in melanin-based coloration. 6. The results also showed that ornamentation, rather than reproduction and survival of adult males, was affected by less favourable conditions. Together with previous results, this suggests that coloration might be more sensitive to changes in environmental conditions than direct fitness proxies.