Abstract Detail

Pollination Biology

De Vos, Jurriaan M [1], Harder, Lawrence D. [2], Edwards, Erika [3].

Evolution of flower number - flower size trade-offs: ecological significance and evolutionary patterns in Lewisia and related genera (Montiaceae).

Understanding of factors and processes affecting the diversification of inflorescences lags far behind understanding of the evolution of floral traits. Theory predicts that, given a finite amount of investment in reproduction, plants can make a limited number of flowers, determined by the particular resource cost per flower. It is poorly understood how the resulting flower number - flower size trade-offs (which are widely documented) evolve among species and whether they constrain evolutionary trajectories of diversification, especially in the face of pervasive evolution of plant body size and resource investment. These issues are explored using Lewisia and closely related genera in Montiaceae - (Portulacineae, Caryophyllales), for which a new phylogenetic marker system is being developed. This group allows for exploring the continuum from few, bigger (e.g. L. rediviva) to many, smaller flowers (e.g. L. columbiana). Based on preliminary sampling, number- and size-traits of flowers (pertaining to various aspects of sepaloids, petaloids, androecium and gynoecium) positively co-vary within and among species. I find evidence for an overall trade-off in flower number per plant and flower "size", between, but not necessarily within species. Deviations from these underlying trends are well explained by evolution of body size: bigger plants can make both bigger and more flowers. The nature of evolution along (or away from) trade-off axes is interpreted through analysis of ecological correlates (patterns of precipitation and temperature). Counterintuitively, my findings predict that plants should have larger flowers in drier habitats, where the climatic window of opportunity for flowering is particularly limited.

1 - Brown University, Department Of Ecology And Evolutionary Biology, 80 Waterman Street, Box G-W, Providence, RI, 02912, USA
2 - University Of Calgary, Department Of Biological Sciences, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
3 - Brown University, Box G-W, 80 Waterman St, Providence, RI, 02912, USA

Keywords:
inflorescence evolution
Trait Covariance
Montiaceae
Caryophyllales
trade-off
floral evolution.

Presentation Type: Oral Paper:Papers for Topics
Session: 32
Location: Firs South/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 9:30 AM
Number: 32007
Abstract ID:659
Candidate for Awards:None