Phenotypic selection on flowering phenology and pollination efficiency traits between Primula populations with...

Area of Science:

• Ecology
• Evolutionary Biology
• Plant Science

Background:

• Floral traits are often shaped by plant-pollinator interactions.
• The precise role of real pollinators in driving floral trait evolution requires further investigation.

Purpose of the Study:

• To quantify pollinator-mediated selection on flowering phenology and floral traits in two populations of *Primula secundiflora*.
• To compare the strength and direction of selection exerted by different pollinator groups.

Main Methods:

• Conducted pollinator observations to identify dominant pollinator species.
• Estimated selection gradients under open and supplemental hand pollination to isolate pollinator effects.
• Analyzed selection on flowering phenology and corolla tube entrance diameter.

Main Results:

• Directional selection favored earlier flowering with syrphid flies, while bumblebees selected for later flowering.
• Stabilizing selection on flowering phenology occurred with syrphid flies; disruptive selection occurred with bumblebees.
• Wider corolla tube entrance diameter was selected in both populations, with stronger selection by syrphid flies.

Conclusions:

• Pollinator assemblages significantly influence the direction and strength of selection on floral traits.
• Pollinator-mediated selection is a key driver of variation in floral evolution between populations.
• Understanding pollinator diversity is crucial for predicting plant evolutionary trajectories.