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Death by Slow Degrees
Because of grave international concerns over rainforest destruction and loss of other
shrinking habitats, many countries have begun putting land aside in nature preserves.
The Endangered Species Act in the US, for example, has prompted the preservation of
such places as Antioch
Dunes National Wildlife Refuge and Lake Wales Ridge State Forest.
In spite of the many noble attempts to save endangered plant species so far, no one is
certain it is adequate. Often the land that is put aside is only a small fraction of
a much larger ecosystem. Nowhere is this concern more acute in the botanical world
than in the poorly understood relationships between plant and their pollinators.
What may appear to be adequate protection for a particular endangered plant, may be
inadequate to assure survival of an associated pollinator. Unfortunately, it appears
that for many plants, loss of a specialized pollinator may represent a slow death warrant
for the plant as well.
From an evolutionary standpoint extreme specialization between a plant species and a
specific, dedicated pollinator is a mixed blessing. Extreme specialization does
assure that high rates of pollen exchange among individuals in the population can occur.
Many orchids of Central and South America are pollinated by euglossine
bees. Some euglossine bees are generalists, but others can be adapted to a
single species of orchid. The bees act as pollinators because they are rewarded with
special scents produced by the flowers. The bees collect these scents and modify
them to produce their own sex attractants.
The most specialized orchids allow the bee to enter the flower in just a single
orientation that causes pollinia (pollen sacs in orchids) to stick to a specific part of
the bee's body. When the bee enters another flower of the same species, the
orientation of the bee causes the pollinia to be removed and the pollen to contact the