Pollen vigour and the potential for sexual selection in plants

TitlePollen vigour and the potential for sexual selection in plants
Publication TypeJournal Article
Year of Publication1991
AuthorsSnow AA, Spira TP

Discovering whether paternal fecundity varies within populations is crucial for evaluating whether male-male competition and/or female choice can lead to sexual selection. In natural populations of plants, pollinators often deposit mixtures of 'surplus' pollen from several individuals onto receptive stigmas. Therefore within-flower competition among pollen-tubes for ovules could lead to nonrandom paternal success. We found that pollen competition was common in populations of wild rose mallow (Hibiscus moscheutos). Co-occurring individuals often differed in mean pollen-tube growth rates, and this trait was correlated with the number of seeds the plants sired when pollen mixtures were applied to stigmas. Differences between pairs of individuals in pollen-tube growth rates were consistent across maternal plants, suggesting that sexual selection can occur. This unexpected variation in pollen vigour could lead to nonrandom fertilization whenever pollen-tubes compete for access to ovules.