Pollen Limitation Is Common--Should It Be?

Area of Science:

• Ecology
• Evolutionary Biology
• Plant Sciences

Background:

• Meta-analyses suggest widespread pollen limitation of seed output in flowering plants.
• A 2014 theoretical model predicted infrequent pollen limitation, contradicting empirical data.
• The model's assumptions regarding fertilization costs and ovule fertilization variance may be unrealistic.

Purpose of the Study:

• To re-evaluate the theoretical model of Rosenheim et al. (2014) concerning pollen limitation.
• To investigate the sensitivity of the model's predictions to its underlying assumptions.
• To reconcile theoretical predictions with empirical observations of plant reproductive success.

Main Methods:

• Analysis of the theoretical model by Rosenheim et al. (2014).
• Sensitivity analysis of model predictions based on varying assumptions about fertilization costs and ovule fertilization variance.
• Comparison of model-generated predictions with empirical data from meta-analyses.

Main Results:

• The model's predictions are highly sensitive to assumptions about prefertilization and postfertilization costs.
• Unrealistically low cost ratios and narrow variance in ovule fertilization in the original model lead to inaccurate predictions.
• More realistic distributions of pollination variation align model predictions with empirical findings of pervasive pollen limitation.

Conclusions:

• Pollen limitation of seed output in flowering plants is likely pervasive, contrary to the 2014 model's predictions.
• The assumptions within the Rosenheim et al. (2014) model require revision to accurately reflect ecological realities.
• Further research is needed to understand the full extent of lifetime pollen limitation in plants.