Masters Thesis

A test of the pollination syndrome concept using the Jamaican Blue Mahoe, Hibiscus elatus

In this study I tested the ability of the pollination syndrome model to predict the most effective pollinator of a tropical forest tree, Hibiscus elatus (Malvaceae), at three sites in Jamaica, West Indies. The floral characteristics of this species suggested pollination by both bees and bats. Bat syndrome traits include large bowl-shaped flowers borne on stout pedicles that open in the late afternoon or early evening, thick and waxy petals, and copious amounts of dilute nectar secreted at night. Bee-related floral traits include brightly colored petals with nectar guides, diurnal nectar secretion, and a sweet fragrance. This combination of floral syndromes did not accurately predict the most common and effective pollinators of these flowers: bats accounted for almost all pollination while day-flying visitors (honeybees, hummingbirds, flies and wasps) and other night-flying-visitors (moths, flies, and wasps) contributed minimally. This conclusion rests on the much higher visit rates of bats, their much higher likelihood of contacting anthers and stigmas during visits, and the fact that > 99% of pollination occurred at night. The bee syndrome traits of H. elatus are probably vestiges inherited from a bee-pollinated ancestor that have been retained due to lack of fitness trade-offs. H. elatus is likely in a transitional state evolving towards increased specialization for pollination by bats.

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