Abstract Detail

Ecology

Braum, Anna [1], Steger, Laura [2], Fant, Jeremie [3].

Maintenance of color polymorphism in the scarlet paintbrush (Castilleja coccinea).

Knowledge of the factors that contribute to the maintenance of polymorphism is key to our understanding of speciation processes. Castilleja coccinea demonstrates polymorphism in floral bract color throughout its range, though little is known about how this variation is maintained. In this study, we sought to correlate distribution patterns of C. coccinea morphs with potential drivers of polymorphic variation in this species. We characterized the spatial distribution of morphs in relation to habitat characteristics across the range of the species, compared fitness and morphology between morphs in regional populations, and established a common garden to examine heritability of floral bract color. Morphs were non-randomly distributed throughout the range of the species, and most populations were comprised of a single morph. Yellow morphs were most common in the upper Midwest, and most frequently associated with open wetlands and high soil organic content. Red morphs were more common at drier sites with greater canopy cover. Shifts in floral color were associated with differences in floral morphology, as well as with higher fitness for the yellow morph under common garden conditions. The distribution of morphs across the range of the species is consistent with selection as the primary driver of polymorphism in this species. Differences in habitat type for each of the morphs are indicative of diversification associated with a shift in ecological niche, while variation in floral structures and fitness between morphs may be associated with adaptation to the pollinator environment.

1 - The Wetlands Initiative, 53 W. Jackson Blvd., Chicago, IL, 60604, USA
2 - Arizona State University, School of Life Sciences, 427 E. Tyler Mall, Tempe, AZ, 85281, USA
3 - Chicago Botanic Garden, Plant Biology and Conservation, 1000 Lake Cook Road, Glencoe, IL, 60022, USA

Keywords:
flower color
Pleiotropy
pollination
polymorphism
Orobanchaceae.

Presentation Type: Oral Paper
Session: 14, Ecology Section - Reproductive Biology
Location: 106/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 2:45 PM
Number: 14006
Abstract ID:697
Candidate for Awards:None