"What is strange here is the method," said Mark Johnston, a plant ecologist at Dalhousie University in Halifax, Nova Scotia.
"It's unique that self-pollination is accomplished in so active a manner."
A Practical Solution
Although the orchid produces no nectar and is self-fertilizing, it retains flower features thought to be attractive to insects (related wallpapers: flowers in bloom).
Study co-author Huang says that's a clue that the flower's evolutionary ancestor relied on insect pollination.
Surprisingly, the orchid even retains features of insect-pollinated species that function to prevent accidental self-pollination.
For example, the female cavity faces downward and is kept separate from the male parts by a beaklike projection called a rostellum.
Given such a structure, Huang says, it is practically impossible for fertilization to occur from pollen delivered by the wind, fluid secretions, or the force of gravity.
Wind-assisted pollination is unlikely anyway, he adds, in the still air of the forest interior where the orchid lives.
For H. amesianum, insect pollination is the only conventional alternative. But in their observations of more than 1,900 of the flowers, the biologists observed no insect visits.
"Insects are absent during the dry, flowering season," Huang said.
With conventional pollination methods either unfeasible or unavailable, "self-copulation is the only practical solution."
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