Sexual Dimorphism in Plant Reproductive Strategies

Sexual dimorphism in plants encompasses the morphological, physiological and phenological differences between male and female reproductive functions. In dioecious species, separate individuals bear only male or only female flowers, leading to trade-offs in resource allocation that shape flower size, display, nectar rewards and pollen production. Gynodioecious populations combine hermaphrodite and female morphs, where differences in floral form and timing of pollen presentation can influence pollinator behaviour and outcrossing rates. In monoecious and sequentially hermaphroditic species, temporal separation of male and female functions within the same individual further generates sex-specific floral traits, such as changes in petal reflectance or nectar secretion. These patterns are driven by the interplay of pollinator preferences, sexual selection, inbreeding depression and environmental resource availability. Understanding these dynamics has global significance for crop breeding strategies, restoration of dioecious taxa in fragmented landscapes and the conservation of pollination networks under climate change.

Research from Nature Portfolio

Recent studies have demonstrated that sexually dimorphic floral traits can actively manipulate pollinator sequences to enhance pollen transfer. In one dioecious tree species, male flowers exhibit more conspicuous petal coloration while female flowers offer higher-quality rewards. Behavioural experiments and simulation models showed that pollinators preferentially move from male to female flowers, suggesting that evolved differences in reward and display serve to maximise cross-pollination efficiency.

Sexual Dimorphism in Plant Reproductive Strategies publication trend

The graph below shows the total number of articles in sexual dimorphism in plant reproductive strategies across all publications each year (not limited to Nature Index journals).

Technical terms

Dioecy: A sexual system in which individual plants produce exclusively male or exclusively female flowers.

Gynodioecy: A mixed sexual system in which populations comprise hermaphrodite and female individuals.

Monoecy: A condition in which a single individual bears both male and female flowers separately.

Sequential hermaphroditism: The temporal separation of male and female functions within the same flower or individual.

Sex allocation: The partitioning of resources between male (pollen) and female (ovule, seed) functions.

Bateman gradient: A measure of the relationship between mating success and reproductive success, indicating the strength of sexual selection.

References

1. Dimorphic flowers modify the visitation order of pollinators from male to female flowers. Scientific Reports (2020).
2. Sexual selection on male but not female function in monoecious and dioecious populations of broadleaf arrowhead (Sagittaria latifolia). Proceedings of the Royal Society B (2022).
3. Sex-differential reproduction success and selection on floral traits in gynodioecious Salvia pratensis. BMC Plant Biology (2019).
4. Sex‐specific floral attraction traits in a sequentially hermaphroditic species. Ecology and Evolution (2020).