Date of Award:
5-1-1995
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Committee Chair(s)
Paul G. Wolf
Committee
Paul G. Wolf
Committee
Vincent J. Tepedino
Committee
Frank J. Messina
Abstract
I examined the reproductive biology and pollination of Ute lady's tresses, Spiranthes diluvialis Sheviak, a rare orchid from Colorado and Utah. S. diluvialis exhibits a mixed-mating system. Outcrossing is promoted by protandrous flowers and by acropetal movement of long-tongued bees (predominantly bumblebees) on inflorescences. However, male and female phases overlap, and flowers are fully self-compatible. No autogamous or agamospermous seed set was observed, indicating a pollinator is required for reproduction. Fruit set and pollinia removal varied greatly within and between flowering seasons. I found evidence for both resource and pollinator limitation of fruit set, and suggest that the limiting factor of fruit set may vary within flowering seasons because of unpredictable resource availability and interactions with pollinators. Land managers must include pollinators and pollen-producing plants in their conservation plans. Effects of pest management programs on bumblebees and the availability of suitable habitat must be considered and mitigated. Management goals should include maintenance of floral diversity because other flowering species may facilitate pollination of S. diluvialis.
Recommended Citation
Sipes, Sedonia D., "Reproduction of the Rare, Riparian Orchid Spiranthes diluvialis: Pollination Ecology, Variations in Reproductive Success, And Implications for Conservation" (1995). Biology. 619.
https://digitalcommons.usu.edu/etd_biology/619
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