In many species, males possess conspicuous characteristics to attract females. These traits often attract predators as well, and males thus may have to balance the conspicuousness of their signals in relation to the prevailing predation risk. Here we develop a theoretical model of optimal signaling and risk-taking behavior for males differing in the attractiveness of their signals. All else being equal, more attractive males should behave more cautiously. Yet this prediction may drastically change if males differ in any additional characteristic, especially if basal mortality rate or signaling costs are higher or if the vulnerability to predators is lower for attractive males. A key insight from our model is that male competition will create a positive feedback so that selection on male risk-taking strategies is acting in opposite directions. If selection acts on one male type to behave more cautiously, this will strengthen selection on males of the other types to take higher risks and vice versa. Our results further demonstrate that the asset-protection principle, which states that individuals with higher future expectations should behave more cautiously, may often be violated. We also offer an alternative to the handicap principle explaining the often found positive association between male ornamentation and viability: attractive males may simply behave more cautiously.

作者：Leif, Engqvist；Nils, Cordes；Klaus, Reinhold

来源：Evolution; international journal of organic evolution 2015 年 69卷 2期