The environmental factors affecting plant reproduction and effective dispersal, in particular biotic interactions, have a strong influence on plant expansion dynamics, but their demographic and genetic consequences remain an understudied body of theory. Here, we use a mathematical model in a one-dimensional space and on a single reproductive period to describe the joint effects of predispersal seed insect predators foraging strategy and plant reproduction strategy (masting) on the spatio-temporal evolution of seed sources diversity in the colonisation front of expanding plant populations. We show that higher seed predation rate in the colonisation front than in the core of the population induces an Allee effect. This Allee effect reduces the founder effect and increases the contribution of seed source from the core to the colonisation front. The exact opposite trend is found when the seed predators are absent. Long distance dispersal enhances such contribution. We demonstrate a novel impact of predispersal seed predationinduced Allee effect: by reducing the founder effects, Allee effect lower the erosion of diversity in expanding population. We use rearrangement inequalities to show that masting has a buffering role: it mitigates this seed predation-induced Allee effect. This study shows that predispersal seed predation, plant reproductive strategies and seed dispersal patterns can be intermingled drivers of the diversity of seed sources in expanding plant populations, and opens new perspectives concerning the analysis of more complex models such as integro-difference or reaction-diffusion equations.