COS 130-5 - Sex specific reproductive components and pollination ecology in Fuchsia microphylla (Onagraceae), a subdioecious shrub

Friday, August 12, 2011: 9:20 AM
9C, Austin Convention Center
Eduardo Cuevas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico and Raúl Jiménez, Universidad Michoacana de San Nicolás de Hidalgo
Background/Question/Methods

In subdioecious populations, male, female and fruiting male individuals coexist. This system gives the opportunity to explore both the contribution of fruiting males on seed production and the pollinator visitation patterns between morphs and therefore the stability of this system in an ecological context. Fuchsia microphylla is a subdioecious shrub where we estimated sex ratio and reproductive components on female and fruiting male individuals in two natural populations. Offspring quality produced by female and fruiting male individuals was evaluated in a greenhouse. We also compare floral display per plant, nectar production, and pollinator visitation rates between morphs.

Results/Conclusions

Flower and fruit production, and fruit mass were significantly greater in female than in fruiting male plants. Viable seed number and their germination rates were not different between morphs but seedlings from female individuals were significantly larger than those from male individuals. Female flowers excluded from pollinators were able to produce viable seeds by apomixis. Corolla diameter and nectar concentration were higher in male flowers but pollinators did not show consistent morph preferences. As expected, a positive association between floral display and number of visits was found for both morphs. Our findings indicate that fruiting males may contribute with a significant amount of viable seeds, therefore in years or populations with low or no pollinator visitation, seed production by males via self fertilization can become relevant.

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