Abstract
In animal-pollinated plants, two factors affecting pollen flow and seed production
are changes in floral display and the availability of compatible mates. Changes in
floral display may affect the number of pollinator visits and the availability of
compatible mates will affect the probability of legitimate pollination and seed production.
Distyly is a floral polymorphism where long-styled (pin) and short-styled (thrum)
floral morphs occur among different individuals. Distylous plants frequently exhibit
self and intra-morph incompatibility. Therefore changes in morph abundance directly
affect the arrival of compatible pollen to the stigmas. Floral morph by itself may
also affect female reproductive success because floral morphs may display differences
in seed production. We explored the effects of floral display, availability of neighboring
compatible mates, and floral morph on seed production in the distylous herb Arcytophyllum lavarum. We found that floral display does not affect the mean number of seeds produced per
flower. There is also no effect of the proportion of neighboring legitimate pollen
donors on seed production in pin or thrum flowers. However, floral morphs differed
in their female reproductive success and the thrum morph produced more seeds. Hand
pollination experiments suggest that differences in seed production between morphs
are the result of pollen limitation. Future research will elucidate if the higher
seed production in thrum flowers is a consequence of higher availability of pollen
donors in the population, or higher efficiency of the pin morph as pollen donor.
Key words
Arcytophyllum lavarum
- Costa Rica - distyly - floral display - Páramo - pollen donors.
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C. García-Robledo
Department of Biology
University of Miami
P.O. Box 24 91 18
Coral Gables, FL 33124-0421
USA
eMail: carlos@bio.miami.edu
Editor: J. T. M. Elzenga
