THE CONSEQUENCES OF POLLINATION BIOLOGY FOR SELECTION OF MASS OR EXTENDED BLOOMING

1. A model is developed to explore conditions that favour mass blooming vs extended blooming. It is assumed that the pollinators arriving at a plant visit all flowers on that plant, that pollen uptake and deposition are constant fractions of amounts on the flower and pollinator, respectively, that seed set is limited by resources, and that there are no seasonal restrictions on flowering. 2. If the number of pollinator visits is independent of the flowering strategy, then it is quite immaterial how many flowers are presented at the same time in a self-compatible (SC) species, whereas presenting flowers one at a time is optimal in a self-incompatible (SI) species. Depending on the values of other parameters, mass blooming can be an evolutionarily stable strategy (ESS) if plants that practice it attract more pollinators. Selection for mass blooming is more likely to occur in SC species than in SI species, if pollinators are scarce and if pollen transfer rates are low. 3. Empirical data are discussed in relation to optimization of flower presentation under time-constraints.