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

Autor: John S. Heywood, Joseph S. Michalski, Braden K. McCann, Kara J. Andres, Allison R. Hall, Amber D. Hartman, Tessa C. Middleton, Amelia Chiles, Sarah E. Dewey, Cay A. Miller
Rok vydání: 2022
Předmět:
Zdroj: American Journal of Botany. 109:1875-1892
ISSN: 1537-2197
0002-9122
DOI: 10.1002/ajb2.16063
Popis: 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.To assess the potential for an evolutionary response to these competing selection pressures, we estimated additive genetic variances (We found significantThe predicted evolutionary decrease in the number of CH flowers available for potential outcrossing, combined with the apparent preclusion of potential diurnal pollinators by the pollen-harvesting activities of sweat bees, suggest that 100% cleistogamy is the likely outcome of evolution in the absence of hawkmoths. However, rare mutations with large effects, such as delaying budbreak until after sunrise, could provide pathways for the restoration of outcrossing that are not reachable by gradual quantitative-genetic evolution.
Databáze: OpenAIRE
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