Frequency-dependent selection and the evolution of continuous cheating strategies in plant-pollinator interactions

We provide a conceptual framework and empirical evidence to support the hypothesis that within-individual and independent variation in floral reward and signal traits represents a continuous, variable cheating strategy. We propose that within-individual variation can reduce the ability of pollinators to punish cheaters and allow plants to save resources, thus acting as an effective mechanism of pollinator manipulation. We present a frequency-dependent model, simulations and analytical determination of equilibria complemented with two empirical cases supporting the hypothesis. Analyses showed that variable strategists are more likely to persist and coexist with cheater plants than with those that offer a predictable amount of reward (honest plants). Despite evidence of pollinator-mediated selection for floral honesty, honesty was not related to the total allocation of reward and dishonest (variable) plants are common in natural populations. Pollinator-mediated frequency-dependent selection can drive the evolution of more effective cheating strategies. Results suggest that honesty is not evolutionarily stable and can be replaced by populations composed of variable and cheater strategists, supporting the idea that within-individual variation in floral rewards and signals, as well as their association, may represent an underrecognized source of variation that can promote the evolution of stable cheating strategies in plant-pollinator interactions. This article is part of the theme issue 'Exploring negative frequency dependent selection across levels: from genetics to ecology and back again'.