Harder, Lawrence D.Borkent, Christopher2005-08-162005-08-1620040612933539http://hdl.handle.net/1880/42183Bibliography: p. 99-113Dioecy is relatively uncommon among flowering plants, occurring in just 6% of species. It is associated with a suite of ecological characters whose role in breeding-system evolution is poorly known. I therefore explored the role of one correlate; generalist fly pollination. Flies acted differently than more specialized pollinators in their visits to plants, by revisiting flowers frequently and not discriminating between the sexes. In comparing dioecious and hermaphroditic species, I found that dioecious species had lower pollen transfer efficiency and pollen receipt, similar pollen removal and seed set, and higher fruit set than hermaphroditic species. Flies produced variance in reproductive characters, such as pollen removal and receipt, equaling that found in hermaphrodites, which should allow dioecious plants to compete effectively with hermaphrodites. Because flies visit plants differently than most other pollinators, their behaviour results in pollination attributes that could promote the evolution and maintenance of dioecy in some plant species.x, 113 leaves : ill. ; 30 cm.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.master thesis10.11575/PRISM/13102AC1 .T484 2003 B67