Evolution of pollination-induced plasticity of flower longevity

In many plants, pollen deposition or removal can lead to early flower senescence, while flowers will live longer when pollination is excluded, and the strength of this pollination-induced plasticity of flower longevity varies across populations. This study builds models to investigate the evolution of the plasticity of flower longevity through group and individual selection under stochastic pollination environments. Generally, stronger plasticity evolves when female and male fitness accrual rates are higher and more volatile, and the evolution of plasticity is also strongly affected by daily maintenance cost of flowers relative to construction costs. Group selection only selects for plasticity in the female function (i.e., ovule fertilization) but not in the male function (i.e., pollen removal), and plasticity is optimal in maximizing fitness only when saved resources through plasticity greatly enhance individual fitness. Plasticity is more likely to evolve under individual selection, but under the same pollination environment, any combination of the plasticity in female and male functions that adds up to a certain overall strength of plasticity can be evolutionarily stable. Given the fact that plasticity in the male function is rare in hermaphroditic populations, the plasticity of flower longevity may evolve mainly through group selection instead of individual selection.