Abstract Detail

Pollination Biology

Krosnick, Shawn [1].

Ornithophilous Pollination Syndromes and the Evolution of Self Compatibility in Australian Passiflora.

Passiflora L. consists of ca. 520 species of vines, lianas and small trees distributed throughout Mexico, Central and South America, with an additional 24 species endemic to the Old World. Flowers in Passiflora are generally open for one day and species are not self-compatible. Insect pollination is the most widespread condition in Passiflora, and recent phylogenetic analyses indicate that insect pollination is plesiomorphic for the genus. Conservative estimates suggest that bird pollination has evolved a minimum of 10 times across Passiflora. Nearly all of the switches to ornithophily represent changes from insect to hummingbird pollination and are accompanied by the production of copious nectar, elongated floral shape, the absence of floral scent, and in some cases, self-compatibility. Interestingly, three species endemic to Australia and the Pacific Islands exhibit similar characteristics to the hummingbird pollinated New World species. Passiflora herbertiana, P. cinnabarina, and P. aurantia have tube-shaped flowers, produce large quantities of nectar, lack scent, are open for several days, and have brightly colored flowers that change color as the flowers age. Moreover, the Australian taxa appear to be self-compatible based on greenhouse observations. Field studies were performed in SE Queensland to document pollination syndromes and to examine the extent of self-compatibility in Passiflora herbertiana. Flowers in P. herbertiana are open for five days. Anthesis begins slowly in the evening, sugar accumulates in the floral nectary overnight, and the flower is completely open the next morning. Nectar production peaks on day three and ceases on day four, by which point the stigmas are recurved near the anthers for possible self-pollination. Three species of Australian Honeyeaters visited P. herbertiana: the Lewin’s Honeyeater, the Eastern Spinebill, and the Noisy Miner. Of these, the Lewin’s Honeyeater was the most frequent with ca. 3 visits to the population observed per day. Self-pollination and manipulated outcrossing studies were performed using three vines ca. 100 meters apart from one another. Gynoecia were collected after 24 hours and assessed for rates of ovule fertilization as a predictor of potential seed-set. Both self and outcrossed gynoecia demonstrated extremely high levels of fertilized ovules (95-100%) suggesting P. herbertiana is fully self-compatible. These data suggest that P. herbertiana and the other Australian species may have evolved self-compatibility as a means to ensure seed set given their more specialized ornithophilous pollination syndrome.

Broader Impacts:

1 - Southern Arkansas University, Department of Biology, 100 East University Street, Magnolia, AR, 71753, USA

Keywords:
Passiflora
Australia
honeyeater
ornithophily.

Presentation Type: Oral Paper:Papers for Topics
Session: 43
Location: Melrose/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 11:45 AM
Number: 43006
Abstract ID:252
Candidate for Awards:None