''Dendrobium christyanum'' is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

(Orchidaceae)

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the Chinese island of

Hainan Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slightly l ...

. It produces a

volatile organic compound Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a ...

that is unrecorded in other plant species. The flowers of this orchid produce a bee

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

which attracts its pollinator, '' Vespa bicolor'', a species of

hornet Hornets (insects in the genus ''Vespa'') are the largest of the eusocial wasps, and are similar in appearance to their close relatives yellowjackets. Some species can reach up to in length. They are distinguished from other vespine wasps by th ...

. The novel feature, first reported in 2009, is supposed to mimic the distress pheromone of the indigenous Asian honey bee ''

Apis cerana ''Apis cerana'', the eastern honey bee, Asiatic honey bee or Asian honey bee, is a species of honey bee native to South, Southeast and East Asia. This species is the sister species of ''Apis koschevnikovi'' and both are in the same subgenus as th ...

'' (the same chemical as in the European ''

Apis mellifera The western honey bee or European honey bee (''Apis mellifera'') is the most common of the 7–12 species of honey bees worldwide. The genus name ''Apis'' is Latin for "bee", and ''mellifera'' is the Latin for "honey-bearing" or "honey carrying", ...

'', which does not occur naturally on Hainan). The chemical compound, (Z)-11-eicosen-1-ol, can be detected by the hornet and is it is assumed this

mimicry In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...

deceives the insect into visiting the flower without reward (the flowers offer no

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

). ''V. bicolor'' preys on honey bees to feed its larvae. The European beewolf (''

Philanthus triangulum The European beewolf (''Philanthus triangulum''), also known as the bee-killer wasp or the bee-eating philanthus (from the now obsolete synonym ''Philanthus apivorus''), is a solitary wasp that lives in the Western Palearctic and Afrotropics. Alt ...

'') is also able to detect this compound when hunting bees. Orchid Mimics Honey Bee Alarm Pheromone in Order to Attract Hornets for Pollination
Current Biology, Volume 19, Issue 16, 1368 – 1372, 6 August 2009,

References

christyanum Endemic orchids of China Flora of Hainan Plants described in 1974 Endangered flora of Asia {{Dendrobium-stub