Why Does the Coryanthes Orchid Have a Weird Shape?

Symbiosis

• There are 30 species of coryanthes that live in Mexico, Central America and South America. They are both epiphytic and myrmecophytic. Epiphytes, also called air plants, cling to trees in rain forests for support only. Myrmecophytic plants have a symbiotic relationship with ants. The seeds and nectar that coryanthes plants produce are food for the ants, which build nests on tree branches around the plant roots. These nests are referred to as ant gardens and give coryanthes extra support as well as nutrients from organic debris accumulated in the nests. The kind of ant nests associated with coryanthes is also called beehive gardens, because they not only house biting ants but also stinging bees, which are another symbiotic partner.

Reliance on Bees

• Coryanthes can't survive without male euglossine bees for pollination. The bees seek a waxy substance produced by coryanthes that helps them attract mates. The substance is located at a precarious spot --- a tube, called the mesochile, connected to the bulbous hypochile where the attractant is produced. The hypochile's connection to the mesochile overhangs the flower bucket. If the bee falls in, it must battle to find a way out because it can't fly with wet wings. If no bee falls in while the plant is at its pollination stage, it can't reproduce. The process is perilous for both bee and plant.

Shape and Survival

• The upside-down-hanging coreyanthes is ungainly. Its front mouth resembles a droopy cabana attached to a strange water feature -- the bucket, into which two tubes from the mesochile drip mucillaginous liquid that is not nectar. It is difficult to obtain pollen from coryanthes plants and equally difficult to pollinate them. Bees crowd to coryanthes during its pollination period because this is the time when the flower produces the sexual attractant they want. While competing to obtain the waxy substance, a bee sometimes slips into the pool below. To survive, it must swim to an exit tube at the mouth end of the bucket.

Successful Pollination

• It takes the bee about 30 minutes to exit. As it crawls up and out through the narrow tube, its back brushes against a twin set of pollen capsules and carries the substance away with it. If the bee visits another coryanthes and falls again, it can fertilize the new plant. The pollen collected from the previous plant remains on its back despite its second swim and is collected by the new plant as the bee makes his way through yet another exit tunnel with his payoff -- the sexual attractant that is still clinging to him.