Overcompensation through the paternal component of fitness in Ipomopsis arizonica.

Estimates of the effects of herbivory on plant fitness based on female fitness alone may be misleading if plants experience either reduced or increased male fitness. Because there are many plants that produce more flowers following herbivory where seed set is unaffected or reduced, total fitness may be enhanced through the paternal component alone. Here we show that herbivory results in an increase in reproductive success due solely to an increase in paternal fitness in the monocarpic biennial Ipomopsis arizonica. These results suggest that overcompensation may be more common than presently thought, requiring a reexamination of the fitness consequences of herbivory for many plant species.