Does floral herbivory reduce pollination-mediated fitness in shelter rewarding Royal Irises?

Florivory, the damage to flowers by herbivores, can make flowers less attractive to pollinators. Even when pollinated, flower consumed by florivores may fail to produce fruit or will produce lower seed set. Despite the widespread evidence of florivory across ecosystems and plant taxa, only a few studies tested experimentally the interaction of florivory and pollination by manipulative study. We studied the effect of two levels of florivory on both pollinator visitation and reproductive success over two flowering seasons in three Iris species. We hypothesized that florivory will reduce pollen deposition due to reduced attractiveness to pollinators, and that fruiting probability and seed set will depend on the extent of florivory. We performed artificial florivory treatments, representing high, low, and no florivory (control) in two experiments. In the first experiment, each of the three floral units of the same flower was subject to either low, high or no artificial florivory, after which we counted the number of pollen grains present on the stigma. In the second experiment, three flowers of the same plant were treated and were further recorded for fruit and seed production. Surprisingly, and against our hypotheses, in all three species no significant effect was found among and between florivory treatments and control, neither in pollen grain deposited nor in fruit and seed set. The results undermine the assumption that flower herbivory is necessarily antagonistic interaction and suggests that florivores are not strong selection agents on floral reproductive biology in the Oncocyclus irises.