Coryanthes
Encyclopedia
Coryanthes, commonly known as Bucket Orchids, is a genus of tropical epiphytic
orchids. This genus is abbreviated as Crths in horticultural trade.
Bucket orchids are an excellent example of coevolution and mutualism, as the orchids have evolved
along with orchid bees (the tribe Euglossini
of the family Apidae
) and both depend on each other for reproduction. One to three flowers are borne on a pendant
stem that comes from the base of the pseudobulbs. The flower secretes a fluid (see Coryanthes alborosea
picture) into the flower lip, which is shaped like a bucket. The male orchid bees (not the females) are attracted to the flower by a strong scent from aromatic oils, which they store in specialized spongy pouches inside their swollen hind legs, as they appear to use the scent in their courtship
dances in order to attract females. The bees, trying to get the waxy substance containing the scent, sometimes fall to the fluid-filled bucket. As they are trying to escape, they find that there are some small knobs on which they can climb on, while the rest of the lip is lined with smooth, downward-pointing hairs, upon which their claws cannot find a grip. The knobs lead to a spout (see the Coryanthes leucocorys
picture), but as the bee is trying to escape, the spout constricts. At that same moment, the small packets containing the pollen
of the orchid get pressed against the thorax
of the bee. However, the glue on the pollen packets does not set immediately, so the orchid keeps the bee trapped until the glue has set. Once the glue has set, the bee is let free and he can now dry his wings and fly off. His ordeal may have taken as long as forty-five minutes. Hopefully, the bee will go to another flower, where, if the flower is to be successful at reproducing, the bee falls once again into the bucket of the same species. This time the pollen packets get stuck to the stigma as the bee is escaping, and after a while the orchid will produce a seed
pod.
The bee, having stored the aromatic oils in his back legs, can then fly off to mate with a female bee.
Charles Darwin
describes his observations and experiments on some species of Coryanthes in his book The Various Contrivances by which Orchids are Fertilized by Insects. However, Darwin thought it was the female bees that were doing the fertilizing, and it was almost 100 years before the role of the male euglossine bees
were revealed in 1961.
http://www.livevideo.com/video/97D589C0C6254284BC9EA9F1888A7D9C/richard-dawkins-lecture-4-the-ultraviolet-garden-2-of-7-.aspx
In a video lecture directed at children Richard Dawkins includes a segment that shows a Euglossine bee being "tricked" by an orchic. The relevant segment is some distance into the nine minute video.
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
orchids. This genus is abbreviated as Crths in horticultural trade.
Bucket orchids are an excellent example of coevolution and mutualism, as the orchids have evolved
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
along with orchid bees (the tribe Euglossini
Euglossini
Euglossine bees, also called orchid bees, are the only group of corbiculate bees whose non-parasitic members do not all possess eusocial behavior. Most of the species are solitary, though a few are communal, or exhibit simple forms of eusociality...
of the family Apidae
Apidae
The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...
) and both depend on each other for reproduction. One to three flowers are borne on a pendant
Pendant
A pendant is a loose-hanging piece of jewellery, generally attached by a small loop to a necklace, when the ensemble may be known as a "pendant necklace". A pendant earring is an earring with a piece hanging down. In modern French "pendant" is the gerund form of “hanging”...
stem that comes from the base of the pseudobulbs. The flower secretes a fluid (see Coryanthes alborosea
Coryanthes alborosea
Coryanthes alborosea is a species of orchid....
picture) into the flower lip, which is shaped like a bucket. The male orchid bees (not the females) are attracted to the flower by a strong scent from aromatic oils, which they store in specialized spongy pouches inside their swollen hind legs, as they appear to use the scent in their courtship
Courtship
Courtship is the period in a couple's relationship which precedes their engagement and marriage, or establishment of an agreed relationship of a more enduring kind. In courtship, a couple get to know each other and decide if there will be an engagement or other such agreement...
dances in order to attract females. The bees, trying to get the waxy substance containing the scent, sometimes fall to the fluid-filled bucket. As they are trying to escape, they find that there are some small knobs on which they can climb on, while the rest of the lip is lined with smooth, downward-pointing hairs, upon which their claws cannot find a grip. The knobs lead to a spout (see the Coryanthes leucocorys
Coryanthes leucocorys
Coryanthes leucocorys is a species of orchid....
picture), but as the bee is trying to escape, the spout constricts. At that same moment, the small packets containing the pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
of the orchid get pressed against the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
of the bee. However, the glue on the pollen packets does not set immediately, so the orchid keeps the bee trapped until the glue has set. Once the glue has set, the bee is let free and he can now dry his wings and fly off. His ordeal may have taken as long as forty-five minutes. Hopefully, the bee will go to another flower, where, if the flower is to be successful at reproducing, the bee falls once again into the bucket of the same species. This time the pollen packets get stuck to the stigma as the bee is escaping, and after a while the orchid will produce a seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
pod.
The bee, having stored the aromatic oils in his back legs, can then fly off to mate with a female bee.
History
Some of the first investigations on Coryanthes were published by Cruger in 1865.Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
describes his observations and experiments on some species of Coryanthes in his book The Various Contrivances by which Orchids are Fertilized by Insects. However, Darwin thought it was the female bees that were doing the fertilizing, and it was almost 100 years before the role of the male euglossine bees
Euglossini
Euglossine bees, also called orchid bees, are the only group of corbiculate bees whose non-parasitic members do not all possess eusocial behavior. Most of the species are solitary, though a few are communal, or exhibit simple forms of eusociality...
were revealed in 1961.
External links
http://www.livevideo.com/video/97D589C0C6254284BC9EA9F1888A7D9C/richard-dawkins-lecture-4-the-ultraviolet-garden-2-of-7-.aspx
In a video lecture directed at children Richard Dawkins includes a segment that shows a Euglossine bee being "tricked" by an orchic. The relevant segment is some distance into the nine minute video.