Abstract Detail

Pollination Biology

Ren, Zong-Xin [1], Wang, Hong [1], Bernhardt, Peter [2], Li, De-Zhu [1].

Fly pollination of Section Trigonopedia in the genus Cypripedium (Orchidaceae).

Charles Darwin used orchid flowers as model systems to explain the evolution of functional morphology and adaptations. However, Darwin did not accept K. C. Sprengel’s concept of pollination-by-deceit, in which floral stimuli attracts pollinators but the flower fails to reward the pollinator. Recent theories insist that floral mimesis or deception appears to drive speciation in the majority of lineages within the terrestrial Orchidaceae. Historically, the genus Cypripedium has been regarded as a model lineage of nonrewarding orchid flowers that tempoirarily trap their pollinators but the majority of species studied, to date, are bee-pollinated. However, China is the center of biodiversity for Cypripedium and the southwestern mountains of China represent the hotspot of diversity for endemic Cypripedium spp. Recent studies indicate that, at least, five Cypripedium species found there are pollinated by flies exploiting a suite of attractant characters known as myophily. Previously, we described a new mode of deceptive pollination in Cypripedium fargesii. This nectarless, critically endangered endemic requires fungus-eating (mycophagic) flies for pollination/fertilization of seeds. Unlike most deceptive orchids, the flower is not the only deceptive organ. In fact, the blackish hairy spotted leaves combine with the floral pigmentation patttern and musty floral scent lure flies that, under normal circumstance, would feed on the fungal exudates of infected vegetation. Theoretically, the leaf and flower mimesis of fungus-infected foliage probably represents a “bridge” between generalist food mimesis, in most Cypripedium spp., and full mimicry of fungal fruiting bodies (sporocarps). Based on molecular evidence, C. fargesii has three-five “sister species” so closely related that they are all now placed in Section Trigonopedia, all found in the same, but broad, southwestern hotspot in China. All of these species have similar pirmentation patterns on their leaves and flowers as C. fargesii. Further field and lab work is required to show whether the same mode of deceptive pollination persists throughout Section Trigonopedia? Do all species attract the same fly species? We propose a morphometric, quantitative and biochemical study to compare pollination modes within the Trigonopedia lineage to determine evolutionary trends in the future.

Broader Impacts:

1 - Kunming Institute of Botany, Chinese Academy of Sciences, Key Laboratory of Biodiversity and Biogeography, 132 Lanhei Road, Kunming, Yunnan, 650201, China
2 - Saint Louis University, Department of Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA

Keywords:
Cypripedium
Deception
pollination
Mimicry.

Presentation Type: Oral Paper:Papers for Topics
Session: 45
Location: Melrose/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 2:15 PM
Number: 45004
Abstract ID:624
Candidate for Awards:None