The pollination of Habenaria rhodocheila (Orchidaceae) in South China: When butterflies take sides
Open Access
- 2 March 2021
- journal article
- research article
- Published by Wiley in Ecology and Evolution
- Vol. 11 (6), 2849-2861
- https://doi.org/10.1002/ece3.7242
Abstract
Habenaria is one of the largest terrestrial genera in the family Orchidaceae. Most field studies on Habenaria species with greenish–white and nocturnal scented flowers are pollinated by nocturnal hawkmoths and settling moths. However, H. rhodocheila presents reddish flowers lacking a detectable scent and fails to fit the moth pollination syndrome. We investigated the pollinators, breeding system, and functional traits of H. rhodocheila in South China and found that two diurnal swallowtail butterflies Papilio helenus and Papilio nephelus (Papilionidae) were the effective pollinators. When butterflies foraged for nectar in the spur, the pollinia became attached between the palpi. A triangular projected median rostellar lobe was found at the entrance (sinus) of the spur of H. rhodocheila. This lobe divided the spur opening into two entrances forcing butterflies to enter their proboscides through the left or right side. When the projection of median rostellar lobe was removed, the site of pollinium attachment changed to the eyes of the butterflies, leading to a higher rate of pollinium removal but lower rate of pollinium deposition. Our quartz glass cylinder choice experiment suggested that visual rather than olfactory cues provided the major stimuli for butterflies to locate these flowers. Hand pollination experiments suggested this species was self‐compatible but pollinator‐dependent. However, the proportion of seeds with large embryos produced in self‐pollinated fruits was significantly lower than in cross‐pollinated fruits, indicating a significant inbreeding depression. Unlike many other orchid species, fruit set was higher than rates of pollinium removal, indicating a high level of pollination efficiency in a species with friable pollinia. Shifts from moth to butterfly pollination in the genus Habenaria parallel other orchid lineages providing insights into the potential for pollinator‐mediated floral trait selection.Funding Information
- National Natural Science Foundation of China (31901078, 31971570)
- Nanchang University
This publication has 65 references indexed in Scilit:
- Pollination biology of four sympatric species of Habenaria (Orchidaceae: Orchidinae) from southern BrazilBotanical Journal of the Linnean Society, 2012
- Pollinator‐mediated selection on floral display, spur length and flowering phenology in the deceptive orchid Dactylorhiza lapponicaNew Phytologist, 2010
- Reproductive biology of Acrolophia cochlearis (Orchidaceae): estimating rates of cross-pollination in epidendroid orchidsAnnals of Botany, 2008
- Hawkmoth pollination of aerangoid orchids in Kenya, with special reference to nectar sugar concentration gradients in the floral spursAmerican Journal of Botany, 2007
- Variation in sexual reproduction in orchids and its evolutionary consequences: a spasmodic journey to diversificationBiological Journal of the Linnean Society, 2004
- Epiphytism and pollinator specialization: drivers for orchid diversity?Philosophical Transactions B, 2004
- Transfer of pollinaria on birds? feet: a new pollination system in orchidsÖsterreichische botanische Zeitschrift, 2004
- Insect pollination and floral mechanisms in South African species ofSatyrium (Orchidaceae)Österreichische botanische Zeitschrift, 1997
- Bird pollination in South African species ofSatyrium (Orchidaceae)Österreichische botanische Zeitschrift, 1996
- Flowers and Insects. XBotanical Gazette, 1893