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Heijerman, T.

AuthorsA. Subedi, R.P. Chaudhary, C. van Achterberg, T. Heijerman, F. Lens, T.J.M. van Dooren, B. Gravendeel
TitlePollination and protection against herbivory of Nepalese Coelogyninae (Orchidaceae)
JournalAmerican Journal of Botany
Keywordsants; Apis cerana; Bombus kashmirensis; Coelogye; herbivory; nectary-modified stomata; Nepal; Otochilus; Pholidota; pollination
Abstract• Premise of the Study: Although many species in the orchid genus Coelogyne are horticulturally popular, hardly anything is known about their pollination. Pollinators of three species were observed in the fi eld in Nepal. This information is urgently needed because many orchid species in Nepal are endangered. Whether the exudates produced by extrafl oral nectaries played a role in protection against herbivory was also investigated.
• Methods: Pollinators of C. fl accida , C. nitida , and Otochilus albus were filmed, captured, and identifi ed. Ant surveys and exclusion experiments were carried out. To investigate whether pollinators are needed for fruit set, plants were wrapped in mesh wire bags. Infl orescence stems were examined with microscopy. Fehling ’ s reagent was used to detect sugars in extrafl oral exudates.
• Key Results: Coelogyne fl accida and C. nitida need pollinators to set fruit and are pollinated by wild bees identifi ed as Apiscerana . Otochilus albus was found to be pollinated by Bombus kashmirensis. Extrafl oral nectar was found to be exuded by nectary-modifi ed stomata and contained high amounts of sugars. Different species of ants were observed collecting these exudates. A signifi cant difference was found in damage infl icted by fl ower and leaf-eating beetles between C. nitida plants living in trees with ant nests and those in ant-free trees.
• Conclusions: Floral syndromes include scented and colored trap fl owers without reward to their pollinators. All orchids investigated exude extrafl oral nectar by nectary-modifi ed stomata. This nectar was found to fl ow from the phloem to the stomata through intercellular spaces in the outer parenchymatous layer of the inflorescence.
Document typearticle
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