<b>Silent Selectors: Hand-Mediated Phenotypic Selection for Floral Display Traits in Greenhouse Tomato (</b><b><i>Solanum lycopersicum</i></b><b>)</b>

Background Understanding how different pollinator species shape phenotypic selection on floral traits is critical for predicting the evolutionary trajectory of the mating system of flowering plants in changing pollination environments. This study examines the differential effects of buzz pollination by bumblebees (Bombus terrestris) and hand pollination on directional and nonlinear phenotypic selection for two floral display traits—flower size and flower number—through female reproductive success in greenhouse tomatoes (Solanum lycopersicum). Results The results indicate that hand pollination drives directional phenotypic selection for increased flower number (β = 0.16 ± 0.04, P &lt; 0.001) and disruptive phenotypic selection for flower size (γ = 0.06 ± 0.03, P = 0.025), whereas bumblebee pollination enhances fruit yield without exerting significant phenotypic selection on the two floral display traits. Conclusions This study demonstrated that hand and bumblebee pollination exert fundamentally different selective pressures on floral traits, suggesting that relying on natural pollinators may maintain floral trait diversity while still optimizing yield. These findings have important implications for conservation, evolutionary biology, and agricultural practices.