Plant-pollinator interaction model with separate pollen and nectar dynamics.

The mutualism between plants and pollinators involves the exchange between plant resources and pollen dispersal services among con-specific plants. Since many pollinators are generalist foragers, the quality of pollination is compromised by inter-specific pollen transfer (IPT). This article proposes a mechanistic approach to model plant-pollinator interactions that considers the dynamics of pollen pick-up and its delivery to con-specific and hetero-specific targets, in parallel but separated from the consumption dynamics of plant rewards by the pollinators. This mechanism can model the interference effect caused by IPT on plant fitness, and predicts saturating effects on the quantity and efficiency of pollination. By coupling the mechanism with population dynamics, the resulting model demonstrates how plant-pollinator associations can shift between net mutualism and parasitism, depending on the ecological context and species traits.