| Abstract Detail
Reproductive Processes Deans, Susan [1], Walsh, Seana [1]. Pollination ecology of the endangered Hawaiian tree species Hibiscus waimeae subsp. hannerae (Malvaceae). Hibiscus waimeae subsp. hannerae is a federally endangered taxon endemic to Kauaʻi, one of the eight main islands making up the Hawaiian archipelago. With possibly as few as 150 individuals persisting in the wild, recruitment failure will mean extinction unless conservation actions are taken. The Hawaiian Islands are home to many unique, codependent plant/pollinator mutualisms which, when disrupted by invasive species, can lead to the decline of one or both obligate partners. Hibiscus waimeae subsp. hannerae is a small tree with large, white, fragrant flowers that stay open throughout the night. These combined traits conform to a moth pollination syndrome. To examine whether flowers of this taxon are attracting sphingid moths, pollinator observations were carried out on cultivated individuals in the Limahuli Garden of the National Tropical Botanical Garden over a period of four months. Floral visitors were photographed or captured for identification. To evaluate the importance of pollinators for seed set, subsets of flowers were either 1) bagged to exclude pollinators, 2) hand self-pollinated, 3) hand outcross-pollinated, or 4) unmanipulated and unbagged as a control. Fruit set, seed set, seed weight, and viability were compared among treatments. All floral visitors were non-native insect and bird species, and most were nectar thieves, visiting the flower without performing the service of pollination. Resting on the pedicel, Japanese white eyes, ants, and honey bees sipped nectar from the calyx tube without coming into contact with anthers or stigmas. Honeybees also were observed foraging for pollen and contacting stigmas in the process, indicating they may be serving as novel pollinators. The most numerous, potentially legitimate visitors were crepuscular hovering moths in the Sphingidae family. At least three species of non-native sphingid moths were observed feeding at the flowers from the front, contacting the stamens and stigmatic surfaces. It remains unclear how successfully these non-native moths are transferring pollen between flowers, or if native moths are still abundant enough to be pollinators. Results from the breeding system study suggest that this species is predominately, physically self-incompatible. For this endangered species heavily reliant upon pollinators for reproduction, competition from non-native nectar thieves could threaten persistence of the species in the wild and native sphingid moths that may depend upon its nectar as a food resource. Log in to add this item to your schedule
1 - National Tropical Botanical Garden - Kalaheo, HI, Science and Conservation, 3530 Papalina Road, Kalaheo, HI, 96741, United States
Keywords: Hibiscus waimeae subsp. hannerae pollination moth pollination novel pollinators nectar thieves breeding system endangered endemic Kauaʻi Hawaiʻi conservation.
Presentation Type: Oral Paper Session: 30, Reproductive Processes Location: Fort Worth Ballroom 7/Omni Hotel Date: Tuesday, June 27th, 2017 Time: 4:15 PM Number: 30010 Abstract ID:198 Candidate for Awards:None |