Pollinators are often given precedence as the primary drivers behind the evolution of floral traits. Yet a growing body of research is beginning to stress the importance of other significant selective agents, particularly the role of herbivores that damage flower and fruit structures.
By experimentally manipulating a population of Lythrum salicaria, Thomsen and Sargent demonstrate that leaf damage alone imposes selection on floral traits and constitutes an even stronger agent of change than selection by pollinators. Herbivores can have a greater impact on floral traits than pollinators, when such floral traits are relevant to a plant’s defense or compensation mechanisms.
Thomsen, C. J. M., & Sargent, R. D. (2017). Evidence that a herbivore tolerance response affects selection on floral traits and inflorescence architecture in purple loosestrife (Lythrum salicaria). Annals of Botany, 119(8), 1295–1303. https://doi.org/10.1093/aob/mcx026