Las Brisas is a private nature reserve located on the lower slopes of Turrialba Volcano in Costa Rica. Our primary goal is conservation and scientific inquiry.
April 1, 2014
We found this intriguingly shaped -- spectacular none-the-less -- Bucket Orchid (Coryanthes sp., very likely C. horichiana) flowering at the reserve. Several aspects about this orchid's natural history are extremely interesting. First of all, in the wild it is found growing almost exclusively in arboreal ant nests. Secondly, this orchid's flower structure is quite complex and highly specialized. Most Coryanthes are pollinated by euglossine bees of the genus Eulaema orEuglossa. The male bees (sometimes of only one species) are attracted to the flower by their fragrance. They attempt to collect this fragrance (an aid to attracting mates) but the waxy flower is difficult to get a firm foothold on, so a bee might slip and fall into the bucket-shaped, waterfilled epichile. The bee's wings get wet when it drops into the fluid filled bucket, which makes flying out of the bucket impossible, and because the walls of the bucket are too slippery, climbing up the steep bucket walls is not an option. The only possible exit is for the bee to crawl up the escape ramp and out the small space between the end of the epichile and the tip of the column. This escape route is visible in the sketch of a dissected flower. The space allowed for the bee to escape is a very tight fit, since the right bee for the job is one that barely fits through the hole. The bee can be caught in the outlet for quite awhile before it finally works its way through. The bee's struggle to free itself loosens the anther cap which frees the pollen so it can be stuck to the back of the bee. The bee is so attracted to the odor that it never learns its lesson, so it continues to search for the source of the fragrance on the same flower or another blossom. Again it falls into the liquid filled bucket of the Coryanthes lip, but this time, as it struggles to leave through the tiny opening, its back is forced against the column and the pollen is deposited into the sticky stigma thereby fertilizing the flower. Notice the green orchid bees hovering around the flowers in the photograph.
This species is very much endangered due to poaching. Most of the poached plants eventually die because they require very specific conditions to survive (usually provided by ants).