| Interactions between flowers and insects have been intensively studied, but the hypothesis on the evolution of floral traits have considered primarily the role of mutualists, and for the most part neglect the interaction with florivores (organisms that eat and destroy flowers). Pollinators and florivores may generate ecological and evolutionary conflicts, and by studying their simultaneous effects, we can gain a better understanding on the evolution of reproductive strategies in plants.; In the first section I review and integrate the existing literature reporting florivores. I find that the Coleoptera, Diptera and Lepidoptera, the insect orders that are considered to include the ancient pollinators, are also the orders in which most florivores are found. This supports the idea that pollination was the result of an antagonistic interaction evolving into a mutualism. I also find that within Diptera and Lepidoptera, there are many species specializing on one or few hosts. In contrast, very few pollinators specialize on only one species of flower throughout their lifetime. Because of their specialization, florivores may be a more powerful selective force on flowers than are generalist pollinators, the "conventionally studied" selective force in flower-insect interactions.; The other sections are field studies on the interaction between Penstemon serrulatus (Scrophulariaceae), and its florivores and pollinators. The florivores are Cecidomyiid flies, whose larvae develop inside P. serrulatus buds, destroying the reproductive structures before the flowers are available to pollinators. The timing of emergence of florivores is highly synchronized with the beginning of flower bud formation, and buds produced early in the season have a higher incidence of attack. In contrast, the pollinators are generalists, active before P. serrulatus begins flowering. The blooming peak of P. serrulatus occurs towards the middle of its flowering season, and pollination visitation increases with the increase in open flowers. Florivores and pollinators appear to affect the flowering phenology of P. serrulatus, selecting for delay of the blooming peak. Buds produced in the middle of the season have the highest chance of producing seeds, by having a higher chance of escaping from florivores, and the plant attracting more pollinators. |
