Sunday, April 22, 2012

Ophrys balearica, proud to be black

The beautiful Ophrys balearica is the unique orchid endemic to the Balearic Islands. Belongs to the Ophrys bertolonii group and it is cousin of Ophrys catalaunica. The blackness and width of its velvety labellum, the metalised brightness of their garnet macula and its gynostem as a small head of a bird are several of its most striking features.

Ophrys balearica flower in early April. This specimen grows in the Serra de Tramuntana in the skirt of a mountain facing the northwest. I recommend enlarge photos with a double click to appreciate its beauty.

As with all orchids, the flowers lack nectar and attract their pollinators with two strategies of imitation or deceit: a structural that mimics the shape and colors of a receptive female and a chemical through the emission of sex pheromones virtually identical to the female insect. Each orchid has a specific pollinator, but this may have several. There are also specialized pollinators in the genus Ophrys that mate indiscriminately with different species of the genus, leading quite often to beautiful interspecific hybrids. The pollinator is always a male. 

Orchids through millions of years of evolution, after testing several experimental mutations have been so perfectly mimic the females of hymenopteran pollinators, bees and bumblebees in general, that males are attracted to their flowers with an irresistible form and copulate with them as if it were true females. In doing so, in the frenzy of copulation, both pollinia loaded with pollen adhere to the head or abdomen of the insect. After copulation the male just flies in search of another female, which logically expected to be true, but for the way it meets the irresistible scent of another false female pheromones and falls back into deception. Coupled with the second false female and in the frenzy of copulation carrying pollinia glued from the first flower pasted into the stigmatic cavity of the gynostem and the second false female is fertilized. Deception has been a success and the orchid has already secured the next generation.

Ophrys balearica initiating flowering in early April. They look good basal leaves and cauline leaf on the stem.

Basal leaves of the previous Ophrys balearica.

 Floral bud opening in early April.

In spring it rains very little in the Balearic Islands. Every four or five years there is a terrible drought. Let the rain in late January and will no longer drop a minimally acceptable rain until late September or early October. Under these extreme conditions the Ophrys balearica has only accumulated reserves in their tiny tuber and flower must absorb water and nutrients from its leaves. The picture shows a specimen without leaves in late April. The tuber has absorbed the entire contents of the leaves and flowers sent to making a titanic effort to get produce seeds, thus ensuring the next generation. 

 To test further the poor orchid the lack of rain prevents grass outbreak, rabbits and hares find nothing to eat and then feed on small basal leaves of orchids, just at the moment in which the stem flower should start to grow. If the drought persists, the whole effort of our beautiful Balearic orchid is useless and rabbits also eat the flowers. It loses a generation of future Ophrys balearica. Underground tuber is unfortunate that dries and disappears. 

 Hopefully sometimes not all is lost, the orchid uses the last of their resources to survive and the old tuber before drying produces one or two tiny tubercles around, that will flower in two years. 

 But do not stop there the calamities of our Ophrys balearica, because sometimes even their tubers are victims of predation by rats and rabbits that they sniff the ground and when they smell the tubers, dig, break through and eat them, undermining of definitely all the titanic effort of the most beautiful orchid in the Balearic Islands.

To further test their ability to survive all orchids of the Balearic Islands have to bear predation on sheep and in recent decades the infernal plague of feral goats that if they find grass and tender shoots of their favorite plants, they feed on the basal leaves and flower stalks of orchids, preventing flower and produce seed the next generation. 

 On farms subject to intensive grazing of sheep is very difficult to find orchids. They are then held in the scrubland and pine forests where sheep graze rarely, preferring to feed on the sparse grass that grows in the open with little tree and shrub vegetation. Goats, by contrast, prefer to browse the tender shoots of shrubs of garrigue and insatiable greed does not respect the young flower stalks of orchids, dramatically accelerating the phasing out of these beautiful plants, especially in mountainous areas of Mallorca.

 In fairness it must be said that most orchid genera Ophrys, Orchis, Anacamptis, Serapias and Himantoglossum they favor a light browsing and grazing to maintain open clear of the garrigue and pine forests, as these plants are eager to sunlight The flowers need to be visible in the eyes of their pollinators. No ultraviolet rays shining on the flowers they are not able to see them, should be directed only by the scent of pheromones emitted from the flower and pollination often does not occur and the ovaries of the flowers are vacuous and dried without producing seeds . Thus, moderate grazing from late spring to early fall not only hurts them but encourages the entry of sunlight and the subsequent production of seeds of the next generation to perpetuate the species.

Although no rain in the cool spring morning dew moisture covers the flowers of Ophrys balearica and helps it to support the extreme drought of our islands.

I remember the excitement I felt several years ago, while photographing the newly opened flowers of Ophrys balearica in a sunny scrubland northwest coast of Majorca, when suddenly a loud black bumblebee, as black as the labellum of the orchid, attracted by the irresistible aroma of false pheromones and pounced on a flower copulating with it in a frenzy. Knowing the great documentary value of a photo of the bumblebee pollinator copulating with the flower of Ophrys balearica, I made few pictures I could in the few seconds that lasted that frenzy, without realizing that was not my digital camera in macro mode. Once back home, I passed pictures to the computer and my disgust was tremendous to see that all had gone blurry and unfocused.

With so refreshing morning swim this flower seems to expect a visit from its eager lover black pollinator.

Picture of an Ophrys balearica flower with details of their anatomy. The strategy of deception is so perfect that the flower has a small yellow appendix at the end of the labellum, called apiculum, which helps the wasp is facing in the intercourse, that is, it know where is the end of the abdomen the false female with the opening for the copulatory organ. The flower has also developed two false ocelli of female, one on each side of the stigmatic cavity. In this way makes the male orchid adopt the correct posture and enter its head with the pollinia attached to it in the stigmatic cavity of the gynostem where are the female organs pollen receptors.

Ophrys balearica fruits in the form of erect and oblong capsules with numerous tiny seeds inside that are dispersed by the wind and the rainwater.

As with all orchids, the seeds to germinate, for lack of nutrient reserves, must find a symbiotic fungus that feeds the seedling in the early stages of germination. They are just a germ cell, a fertilized egg surrounded by a thin sheath cells that protect it. If the seed gets lucky and falls near a freshly germinated spores of specific mycorrhizal fungi, the filaments of the mycelium detected it, like a spider web around her in an embrace of mutual cooperation and stimulate germination by secreting a hormone that raises the cell germ of its lethargy. In the absence of nutritional reserves, the embryo of the orchid in the early cell divisions must receive the nutrients provided by the filaments of the mycelium. Only then can continue the process of germination. When the orchid seedling take their first roots, it form an intimate union with the mycelium, a mutualistic symbiosis, a marriage of convenience that will last the life of the orchid. The filaments of the fungi provide water and minerals to the roots and they will return the favor supply carbohydrates synthesized by the chloroplasts of leaf photosynthesis.

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