PARENT SESSION
Poster Session #37: Plant Ecology: Populations.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Relating pollination-syndrome characters and flower-visitor spectra among species of Penstemon.

Wilson, Paul^*,1, Castellanos, Maria Clara², Thomson, James², ¹ Dept of Biology, Northridge, CA² Dept of Zoology, Toronto, ON, CANADA

ABSTRACT- There has been much controversy as to the relationship between a flower's characters and the types of animals that principally pollinate the flower. Statistical analysis of comparative data, however, have been nearly non-existent. We therefore measured for 49 species of Penstemon and close relatives both the morphology of the flowers and visitation by pollinators of various sorts. Ordinations show that hummingbird-pollinated species and bee-pollinated species form distinct clusters, although the gap between clusters becomes blurred if only continuous characters are studied. Ordinations of only the bee-pollinated species show weaker relationships between morphology and the size of the principally pollinating bees. After having separated flower species into bee- versus bird-pollination syndromes, we contrasted the syndromes in terms of nectar rewards. Hummingbird-pollinated species produced significantly more nectar that was less concentrated and had a higher sucrose:hexose ratio.

KEY WORDS: pollination, floral evolution, comparative biology, Penstemon