Abstract Detail

Pollination Biology

Dupree, Katharine [1], Wilson, Mark [1].

Floral micromorphology and evolution of pollination by sexual deceit in Pleurothallis R.Br. (Orchidaceae; Pleurothallidinae) subgenera Ancipitia and Scopula..

While pollination by sexual deceit is frequent in Orchidaceae, it is not common in genus Pleurothallis in which the majority of species exhibit reward-pollination. In a study on pollination syndromes and evolution of sexual deceit in Pleurothallis, we focused on related subgenera Ancipitia and Scopula, since both contain species that could be pollinated by sexual deceit. To address the hypothesis that pollination by sexual deceit has evolved multiple times in genus Pleurothallis we examined floral (particularly labellum and column) micromorphology by SEM to infer pollination mechanism. Based on labellar micromorphology we assigned each species to a putative pollination syndrome: reward, reward-deceit or sexual-deceit. Putative pollination syndrome was mapped onto a phylogeny derived from nrITS and plastid matK. The species from subgenera Ancipitia and Scopula formed a single strongly-supported clade within subgenus Pleurothallis; proposed section Ancipitia/Scopula. Within section Ancipitia/Scopula there was a strongly supported clade representing former subgenus Scopula; proposed subsection Scopula. Based on floral micromorphology and putative pollination syndrome, pollination by sexual deceit appears to have evolved at least three times in section Ancipitia/Scopula: (i) The species P. crocodiliceps has a very small, but elaborate labellum that presumably mimics a female fly. Examination of plants from the geographic range of Mexico to Peru shows considerable variation in size and form of this labellum suggesting that “P. crocodiliceps” is probably a species complex with each species conceivably pollinated by a different Dipteran; (ii) The species P. gratiosa has a labellum that suggests pollination by pseudocopulation, but which is very different from that of the P. crocodiliceps-complex; and (iii) Pleurothallis sp. nov. Baquero & Tobar, from proposed subsection Scopula, in which all of the other species appear to be pollinated by reward or reward-deceit, exhibits a labellum very similar to that of the P. crocodiliceps complex. Together with two new species being described in subgenus Pleurothallis sections Macrophyllae-Fasciculatae and Acroniae that are probably pollinated by pseudocopulation, this suggests that within subgenus Pleurothallis alone, pollination by sexual deceit has evolved at least five times.

1 - Colorado College, Organismal Biology and Ecology, 14 East Cache La poudre, Colorado Springs, CO, 80903, USA

Keywords:
none specified

Presentation Type: Poster
Session: P, Pollination Biology Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPL004
Abstract ID:197
Candidate for Awards:None