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http://hdl.handle.net/2148/517
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| Title: | Pollination biology of Darlingtonia californica, the California pitcher plant |
| Authors: | Meindl, George A. |
| Thesis Advisor: | Mesler, Michael R. |
| Keywords: | Darlingtonia californica
Andrena nigrihirta
Pollination
Xenogamy
Autogamy |
| Issue Date: | Dec-2009 |
| Publisher: | Humboldt State University |
| Abstract: | The flowers of the California pitcher plant, Darlingtonia californica, are unusual and have been the subject of much speculation. Despite the efforts of several workers, the pollination ecology of this plant, including the identities of pollinators, remains enigmatic. Along with determining visitation frequency, this study sought to describe the relative contributions of two documented floral visitors, bees and spiders. Fruit and seed production by emasculated flowers were used to estimate levels of cross-pollination in natural populations of D. californica. Under the assumption that bees predominantly act as cross-pollinators and spiders as self-pollinators, this treatment was used to infer which organisms were responsible for pollen transfer. Levels of pollen-limitation were also assessed at five study sites in northwest California. In order to identify floral visitors, extensive pollinator surveys were conducted. A generalist solitary bee, Andrena nigrihirta, was found to visit D. californica flowers near Scott Mountain and Mt. Eddy, CA. Despite relatively low visitation rates, individual flowers at all study sites were expected to receive at least one visit by A. nigrihirta. Other regular floral visitors included thrips and several species of spiders. Fruit and seed production by emasculated flowers indicated the occurrence of cross-pollination. Unmanipulated flowers produced more fruits and seeds, on average, compared to emasculated blooms, suggesting that self-pollination contributes to D. californica reproductive success as well. While bees were likely responsible for the majority of cross-pollination, both bees and spiders contributed to autogamous pollen transfer. Following observations of floral visits by A. nigrihirta, it was possible to interpret the functional morphology of D. californica’s flowers. The shape of D. californica’s ovary and petals promote stigma contact both when pollinators enter and exit a flower, contrary to previous thought. This system provides an excellent example of the importance of identifying and observing pollinators in order to truly understand the functional significance of a plant’s floral morphology. |
| Description: | Thesis (M.A.)--Humboldt State University, Natural Resources: Biology, 2009 |
| URI: | http://hdl.handle.net/2148/517 |
| Appears in Collections: | HSU Masters Theses
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