Abstract Detail

Pacific Biogeography

Yomai, Viann Marie [1], Williams, Joseph [1].

Breeding systems on small, isolated islands: Malvaceae, Melastomataceae, and Fabaceae on Pohnpei, Micronesia.

There is a wide gap in understanding factors that facilitate successful colonization of islands by plants, and this is especially true of the Federated States of Micronesia (FSM), a group of islands that stretches from the middle of the Pacific, just north of the equator, to Southeast Asia. Reproductive traits that determine breeding systems should be excellent candidates for directly observing “factors” that allow successful colonization on islands. Because colonizers of isolated islands are initially rare and few pollinators are available, species that persist are likely to reproduce via self-pollination or by wind-pollination. In this study, we focused on testing for self-compatibility, pollen ovule (P:O) ratios, dichogamy/herkogamy, and observations of floral traits associated with pollination system. We chose to work on three families – Fabaceae, Malvaceae, and Melastomataceae – based on their variation in colonization status (native, endemic, invasive) and availability of data for mainland relatives. We carried out experiments and observations on 26 species in Pohnpei, the capital state of FSM. Our results showed that all 26 species were hermaphroditic, and of 11 species that were hand-pollinated, all were self-compatible. Three of the 11 self-compatible species on Pohnpei are known to be self-incompatible in Hawaii and Southeast Asia. Floral traits related to pollinator attraction showed floral sizes were generally smaller compared to their mainland relatives. P:O ratios ranged from 9.28 to 557.37, and the median was 87.13. Based on our results, we concluded that all but one species are either obligately or facultatively selfing. These results support the idea that self-compatibility is overrepresented on islands with tropical rainforests, where wind pollination is not a workable option.

1 - University Of Tennessee, Ecology And Evolutionary Biology, 1406 Circle Drive, Hesler 341, Knoxville, TN, 37996, United States

Breeding System
Pollen ovule ratio
reproductive biology.

Presentation Type: Colloquium Presentations
Abstract ID:531
Candidate for Awards:None

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