Dazzling colours, intricate forms and a fascinating reproductive strategy characterise the terrestrial orchids of the genus Ophrys. Sometimes known as bee orchids, these plants are exclusive to the Old World and are found throughout western Europe, the Middle East and the coastal fringe of North Africa.
A few species extend north to the British Isles and in the case of the Fly Ophrys, Ophrys insectifera, even into southern Scandinavia. It is the Mediterranean region, however, that is the undisputed stronghold of these remarkable orchids.
A Dynamic Genus
Botanists are undecided as to the number of species in this complex genus. Orchids are believed to be the youngest and most highly evolved family of flowering plants and many groups appear to be actively evolving.
In the case of the genus Ophrys, this dynamic process has created a host of subspecies, variations and natural hybrids. In addition, many confusing synonyms abound and distinct sources give wildly differing estimates of between 30 and 140 species .
A typical bee orchid is a herbaceous plant with a basal rosette of three or more, lanceolate to oval leaves, an erect stem bearing several smaller clasping leaves, and from two to twelve flowers.
Growth is stimulated by falling temperatures and the onset of autumnal rains. The roots and shoot emerge from the top of a spherical or ellipsoid tuber, producing a ground-hugging rosette of foliage capable of enduring severe winter conditions.
During the winter and spring, the plant draws on the stored food in the old tuber as it slowly matures and prepares to flower. At the same time, one of the roots expands to form a new tuber which will in turn will provide nutrients for the following season. It is these paired storage organs that endowed all orchids with their family name, because orkhis is the classical Greek for "testicle".
Most bee orchids flower from March to May but some can bloom in January or as late as July. After pollination, they produce elongate capsules that dry and split to release thousands of tiny seeds. The old tuber shrivels, the foliage dies, and a plump new tuber rests deep underground throughout the baking Mediterranean summer, ready to begin the cycle all over again.
Ophrys and the Art of Deception
As with other orchids, the flowers of Ophrys have three sepals and three petals, one of which is modified to form a conspicuous lip. Of all the European orchids, however, it is the bee orchids that have taken this process to extremes in order to deceive their insect pollinators.
Depending on the species, the lip is divided into three equal or uneven lobes. Some are covered with a neat velvety coat, others are fringed with dense hairs. In colour and design, the lip is frequently etched with intricate patterns and contrasts dramatically with the other five tepals. Some species, including Ophrys fusca and Ophrys bombyliflora, have a rich red-brown or maroon lip. Others - most notably the aptly-named Mirror Ophrys, Ophrys speculum - shimmer with a most un-floral metallic blue.
It is hard to ignore the similarity between these blooms and the plump, hairy body of an insect. This, indeed, is exactly the impression the orchid is seeking to create, because Ophrys are pollinated mainly by solitary mining bees (Andrena and Eucera), and always by the male of the species.
Irresistible Aromas of Ophrys
Although the orchids closely mimic the appearance of an enticing and sexually receptive female bee, the prime attractor is in fact a chemical stimulant called an allomone. These allomones simulate the sexual pheromones of the female bee so closely that the male is completely deceived.
Once he has followed the enticing chemical trail to its source, the male bee is further tricked by the orchid´s appearance into believing he has found a mate. The thick, furry lip of the orchid provides an ideal landing platform, and he attempts to copulate with the bogus female.
During his futile attempts, the male bee´s head or abdomen comes into contact with a specialized organ called the pollinium, a pair of pollen sacks at the end of a detachable stalk with an extremely adhesive base. This easily becomes attached to the frustrated insect, who eventually abandons his false bride. However, if the orchid is fortunate he will seek out another flower of the same species, make the same mistake, and transfer the pollen to the receptive stigma.
Conservation of the Ophrys Species
Although some Ophrys species are relatively common and can be found in huge extended colonies, many are threatened and many have become extremely rare.
The decline of traditional agricultural practices and the so-called "improvement" of ancient pasture is a particular problem. European orchids are primarily plants of undisturbed land. They rely in part on a symbiotic relationship with fungi known as mycorrhiza to supply them with water and nutrients via their roots, and any disturbance to their fragile habitats can spell doom for these specialized plants.
In southern Spain, for example, Ophrys speculum, Ophrys lutea and other species of bee orchid are often found on undisturbed road verges or rough hillsides where they are vulnerable to highway maintenance operations and indiscriminate construction schemes.
It is a sad fact that despite increasing appreciation of these marvelous plants, the destruction of such unregarded floral edens is still too often seen as an improvement, rather than the loss of natural treasures as precious as any human work of art.
References
Janet Marinelli (Editor-in-chief): Plant Dorling Kindersley Ltd; London 2004: ISBN 0 7513 4797 3
Sven Nilsson: Orchids of Northern Europe Penguin Books Ltd; Harmondsworth 1979: ISBN 0 14 063.014 7
Manuel Becerra Parra, Estrella Robles Domínguez: Guía de campo de las orquídeas silvestres de Andalucía Editorial La Serranía; Ronda 2009: ISBN 978 84 96607 70 5
Peter Ashby - Peter Ashby lives near Granada in southern Spain, is an expert on natural history, and a dedicated traveller, writer and hispanist.
