The duplicity of orchids is well
documented. Bees, for example, are tricked by orchids that disguise themselves
as the brightly coloured flowers of neighbouring plants.
However, researchers have noted a new twist
to this botanical decpetion. The Oncidiinae group of orchids is one of the most
diverse groups of flowering plant in the world, with around 1700 different
species being found across South and Central America.
What is intriguing is that most of them are
able to attract pollinators without rewarding them with the valuable oil or
nectar which they receive from other flowers.
In the plant world, successful
fertilisation involves attracting pollinators, such as bees, to transfer pollen
from one flower to another, usually in return for a reward.
Researchers from Imperial College London
and Kew Gardens have noted that a specific orchid, the Trichocentrum ascendens
from South America, of the Oncidiinae group, does not do this.
In a ten-year study published in the
journal Proceedings of the Royal Society B, they report that the Trichocentrum
tricks pollinators by closely mimicking the colour and flower shape of another
plant family, the Malpighiaceae, whose flowers produce a plentiful supply of
oil.
Vincent Savolainen, Professor of Organismic
Biology in Imperial's Department of Life Sciences, explains: "These
reward-giving flowers have evolved a very special colour called bee-UV-green,
that is highly distinguishable to bees' sensitive eyes. The Trichocentrum
ascendens and other Oncidiinae orchids copy the special colour so precisely
that bees are unable to distinguish between the flowers, visiting an orchid and
pollinating them without the reward they may expect."
It could be that not producing nectar means
the sneaky orchid can divert more energy to growing strong and producing more
successful future generations.
Caption: Stigmaphyllon sp. (centre;
Malpighiaceae) and Oncidiinae orchids Trichocentrum ascendens and Rossioglossum
ampliatum (left and right; Oncidiinae: Orchidaceae)
Comments
Post a Comment