Pollinator-Mediated Selection on Floral Traits and Color Variation

Flower colour and form represent key interfaces between plants and their pollinators. Variation in petal hue, pattern and morphology can influence pollinator attraction, foraging efficiency and ultimately plant reproductive success. Pollinator-mediated selection arises when differences among floral phenotypes confer differential visitation rates or pollen transfer, driving directional or stabilising selection on traits such as colour intensity, ultraviolet patterning, symmetry and display size. Floral polymorphisms may be maintained by spatio-temporal shifts in pollinator communities, fitness trade-offs among morphs or heterozygote advantage. Abiotic factors including temperature, light and moisture often interact with biotic agents to shape pigmentation and form. Recent advances combine molecular, phenotypic and ecological approaches to link pigment biosynthesis pathways with pollinator behaviour, revealing mechanisms underpinning floral diversification. Understanding these processes is crucial for conserving pollination networks under global change and for improving crop pollination through targeted breeding of floral signals.

Research from Nature Portfolio

One seminal study has demonstrated genuine overdominance in a wild orchid, where three colour morphs—white, red and black—are controlled by variants in an anthocyanidin synthase regulatory gene. Heterozygous individuals producing red flowers attracted both bee and fly pollinators more evenly than either homozygote, leading to higher seed set without deleterious effects. Metabolomic and transcriptomic analyses pinpointed differences in cyanidin pigment concentration and the action of an R2R3-MYB transcription factor. This work provides a clear example of pollinator-mediated maintenance of non-deleterious floral polymorphism via heterozygote advantage and highlights the power of combining genetic and ecological data to unravel selection dynamics in natural populations.

Pollinator-Mediated Selection on Floral Traits and Color Variation publication trend

The graph below shows the total number of articles in pollinator-mediated selection on floral traits and color variation across all publications each year (not limited to Nature Index journals).

Technical terms

Pollinator-mediated selection: Differential reproductive success of plant phenotypes driven by pollinator preference or behaviour.

Floral polymorphism: The occurrence of two or more distinct flower forms or colours within a species.

Anthocyanin: A class of water-soluble pigments responsible for red, purple and blue hues in petals.

Overdominance: A form of selection in which heterozygous genotypes have higher fitness than either homozygote.

Transcription factor: A protein that binds DNA to regulate expression of target genes, including those in pigment pathways.

References

1. Maintenance of flower color dimorphism in Ophiorrhiza japonica (Rubiaceae): responses to fluctuating temperatures in a dolomite Karst region. Frontiers in Plant Science (2024).
2. Flower color polymorphism of a wild Iris on the Qinghai-Tibet plateau. BMC Plant Biology (2023).
3. Emergence of a floral colour polymorphism by pollinator-mediated overdominance. Nature Communications (2019).