DATWYLER, SHANNON*, DANA HUEBERT, and GEORGE WEIBLEN. Department of Plant Biological Sciences, University of Minnesota, 220 Biological Sciences Ctr., 1445 Gortner Ave., St. Paul, MN 55108. - Inflorescence evolution and the origin of a pollination mutualism in Moraceae.
The mulberry family Moraceae include 37 genera and approximately 1100
species displaying spectacular variation in inflorescence
architecture, breeding systems, and pollination syndromes, with the
majority of diversity occurring in Ficus. Inflorescences vary
from solitary flowers and simple spikes to capitula and the urceolate
syconium of Ficus. Breeding systems range from monoecy to
dioecy in the family, with pollination syndromes including wind and
highly specialized wasps in Ficus. Fig pollination is
considered a model system for the study of coevolved mutualism due to
the co-dependent life cycle of figs and fig wasps. However, the
evolution of the fig inflorescence has remained enigmatic because of
its highly derived structure. Several evolutionary pathways to the
syconium have been suggested. We are currently examining relationships
among Moraceae to evaluate phylogenetic hypotheses on the origin of
morphology associated with fig pollination. Sequences from the
chloroplast gene, ndhF, provide a wealth of information on
Moraceae relationships. Preliminary results suggest that the syconium
may have evolved from an urn-shaped inflorescence similar to that of
several insect-pollinated Artocarpeae and Castilleae. These data
enhance our knowledge of subfamilial relationships in Moraceae, and
sequences of change in reproductive traits associated with the origin
of coevolved mutualism in Ficus.
Key words: coevolution, Ficus, inflorescence evolution, Moraceae, ndhF