The potential for floral evolution in response to competing selection pressures following the loss of hawkmoth pollination in Ruellia humilis.

Premise: In the absence of hawkmoth pollinators, chasmogamous (CH) flowers of Ruellia humilis self-pollinate by two secondary mechanisms. Other floral visitors might exert selection on CH floral traits to restore outcrossing, but at the same time preferential predation of CH seeds generates selection to increase the allocation of resources to cleistogamous (CL) flowers.

Methods: To assess the potential for an evolutionary response to these competing selection pressures, we estimated additive genetic variances ( ) and covariances for 14 reproductive traits and three fitness components in a Missouri population lacking hawkmoth pollinators.