PARENT SESSION
Oral Session #5: Plant Demography and Reproductive Ecology.
Presiding: R. Kobe
Monday, August 5. 8:00 AM to 11:30 AM. Coconino Meeting Room, TCC.

Severe genetic cost of reproductive assurance in Aquilegia canadensis.

Herlihy, Christopher^*,1,2, Eckert, Christopher¹, ¹ Queen's University, Kingston, Ontario, CANADA² herlihyc@biology.queensu.ca

ABSTRACT- The transition from outcrossing to self-fertilization is one of the most common evolutionary trends in flowering plants. Reproductive assurance, where self-fertilization ensures seed production when pollinators and/or potential mates are scarce, is the longest standing and most widely accepted explanation for the evolution of selfing, but there have been few experimental tests of this hypothesis. Moreover, many apparently adaptive floral mechanisms that ensure autonomous production of selfed seed may use ovules that would have otherwise been outcrossed. This seed discounting will be costly if selfed offspring are less viable than their outcrossed counterparts, as is often the case. The fertility benefit of reproductive assurance has never been examined in light of the cost of seed discounting. We combine experimental measures of reproductive assurance with marker-gene estimates of self-fertilization, seed discounting and inbreeding depression to show that during 2 years in 10 Ontario populations of Aquilegia canadensis (Ranunculaceae), reproductive assurance through self-fertilization increased seed production, but this benefit was greatly outweighed by severe seed discounting and strong inbreeding depression.

KEY WORDS: self-fertilization, reproductive assurance, seed discounting, inbreeding depression