Abstract Detail

Reproductive biology

Ivey, Christopher T. [1].

Mating system phenology in Mimulus guttatus.

Flowering phenology and mating system are components of plant life history that often have a strong influence on plant fitness. I examined the potential for interactions between these components in a wild population of Mimulus guttatus, an annual herb that produces one to many flowers in its life. Throughout the approximately six-week flowering period of the population, I marked cohorts of co-flowering individual flowers on a total of 200 plants. These plants also captured the range of initial flowering dates of plants within the population. At season’s end, I collected fruits, noting both capsule node position and flowering cohort. I used MLTR to estimate outcrossing rates in plants and capsules, based on allozyme variation in arrays of their progeny. Outcrossing rates among cohorts of flowers varied about 25% throughout the season, with lowest rates among early-opening flowers and highest rates among mid-season flowers. Comparisons of outcrossing rates among groups of plants with different initial flowering dates, however, including all seeds produced by those plants, were not significant. In addition, there were no significant differences in the outcrossing rates of fruits developing from different nodal positions. These results suggest that the variation observed in outcrossing rate was not attributable to plant developmental patterns, but instead due to environmental variation in ecological factors influencing outcrossing rates. Given a nonzero level of inbreeding depression, such variation in outcrossing suggests a temporally dynamic landscape of selection influenced by the ecological circumstances prevailing when a flower is open.

1 - California State University, Biological Sciences, 400 W 1st St., Chico, CA, 95929-0515, USA

Keywords:
Mimulus
outcrossing
phenology
mating system
natural selection.

Presentation Type: Oral Paper:Papers for Topics
Session: 2
Location: Salon 1/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:00 AM
Number: 2005
Abstract ID:522
Candidate for Awards:None