ORCHIDACEAE Juss. Fortnight: Amazing world of Bee Orchids : 10 posts by 8 authors.
The genus Ophrys is a large group of orchids from the alliance Orchis in the subtribe Orchidinae. These plants are remarkable in that they successfully reproduce through pseudocopulation, that is, their flowers mimic female insects to such a degree that amorous males are fooled into mating with the flowers, thereby pollinating them. There are many natural hybrids. The type species is Ophrys insectifera L.1753
They are referred to as the “Bee orchids” due to the flowers of some species resemblance to the furry bodies of bees and other insects. Their scientific name Ophrys is the Greek word for “eyebrow”, referring to the furry edges of the lips of several species.
Ophrys was first mentioned in the book “Natural History” by Pliny the Elder (23-79 AD).
They are terrestrial or ground orchids from central to South Europe, North Africa, Asia Minor, up to the Caucasus Mountains, but mostly in the Mediterranean region. They have been said to be the most important
group of European terrestrial orchids.
During summer, all Ophrys orchids are dormant as underground bulbous tubers, which serve as a food reserve. In late summer/autumn they develop a rosette of leaves. Also a new tuber starts to grow and
matures until the following spring; the old tuber slowly dies. The next spring the flowering stem starts to grow. During flowering the leaves have already started to wither.
Most Ophrys orchids are dependent on symbiotic fungi. Transplanting specimens, especially wild specimens, is difficult, sometimes impossible, due to this symbiosis unless a large amount of surrounding earth is also taken with the plant. All orchids are protected under CITES II and should not be removed or disturbed in habitat.
The shiny, basal leaves have a green or bluish color. Two to twelve flowers grow on an erect stem with basal leaves. These species are successfully cultivated by specialist growers of terrestrial orchids and are reported to be difficult to grow, being sensitive to rotting and damping off diseases if not properly subjected to a cool and dry aestivation period over the summer months with no water.
Orchids of the genus Ophrys use sexual deception to attract pollinators to their flowers. In sexual deception, an orchid attracts male pollinators by producing the sex pheromone of virgin female pollinators in addition to providing visual and tactile cues (Schiestl 2005; Schluter et al. 2009; Stokl et al. 2009). These signals stimulate mating behavior in the male pollinators, which then attempt copulation, called “pseudocopulation”, with the orchid labellum (Schluter et al. 2009). During pseudocopulation, pollen from the flower’s column becomes attached to some part of the pollinator, usually the head or abdomen, and the pollinator inadvertently carries
and transfers this pollen to other flowers when they are once again enticed into pseudocopulation. While the morphological cues such as the shape and texture of the labellum play a role especially at close range in inducing the pollinator mating behavior, the orchid’s pheromone mimic, or allomone, has been shown to play the most important role in enticing pollinators to the flower (Schiestl 2005; Schluter et al. 2009).
The allomone produced by an orchid is specific to its pollinator, of which it usually only has one (Ayasse et al. 2007; Gogler et al. 2009, Schluter et al. 2009) . The allomone is a mixture of alkenes and alkanes (Schiestl and Cozzolino 2008). There are one or more active species in this mixture that account for the attraction of pollinators (Vereeken and Schiestl 2008). Pollinators and orchids use the same chemical compounds in the same absolute amounts in their pheromones and allomones, respectively (Schiestl 2008).
Every Ophrys orchid has its own pollinator insect and is completely dependent on this species for its survival. Duped males are less likely to return and may ignore other plants of the same species. Only about 10% of an Ophrys population gets pollinated. This is enough to preserve the population, since each Ophrys orchid produces about 12,000 minute seeds.
The number of species recognized within the genus varies very widely between authorities. Flora Europaea in 1980 and Pedersen & Faurholdt in 2007 listed about 20 species in Europe as a whole; Buttler in 1991 increased this to 53 for slightly larger geographical area; Delforge in 1995 gave a total of 130 species. By contrast, a molecular phylogenetic study in 2008 suggested that there were around 10 distinguishable groups. As of March 2012, the World Checklist of Selected Plant Families recognizes 34 species of Ophrys worldwide, along with their subspecies.
It was really memorable for me too when I saw them in wild. In two days I saw 6 species…. just kind of heavenly experience.
Ophrys are truly marvels of evolution. A very peculiar case of trans-kingdom production of some very complicated chemicals. Plants may be stationary, non speaking or thinking living things but they are certainly clever enough to fool the insects. Great evolutionary relationship…coevolution at work.
You all will be surprised that even with so much high profile modifications in labellum, there are still some species like Ophrys apifera which is actually shows self pollination in nature.